HPACK - Header Compression for HTTP/2.0
draft-ietf-httpbis-header-compression-04

This document describes HPACK, a format adapted to efficiently represent HTTP header fields in the context of HTTP/2.0.

Editorial Note (To be removed by RFC Editor)

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1. Introduction

This document describes HPACK, a format adapted to efficiently represent HTTP header fields in the context of HTTP/2.0 (see [HTTP2]).

2. Overview

In HTTP/1.X (see [HTTP-p1]), header fields are sent without any form of compression. As web pages have grown to include dozens to hundreds of requests, the redundant header fields in these requests now pose a problem of measurable latency and unnecessary bandwidth (see [PERF1] and [PERF2]).

SPDY [SPDY] initially addressed this redundancy by compressing header fields with Deflate, which proved very effective at eliminating the redundant header fields. However, that aproach exposed a security risk as demonstrated by the CRIME [CRIME].

In this document, we propose a new compressor for header fields which eliminates redundant header fields, is not vulnerable to CRIME style attacks, and which also has a bounded memory cost for use in constrained environments.

2.1. Outline

The HTTP header field encoding described in this document is based on a header table that map (name, value) pairs to index values. Header tables are incrementally updated during the HTTP/2.0 session.

The encoder is responsible for deciding which header fields to insert as new entries in the header table. The decoder then does exactly what the encoder prescribes, ending in a state that exactly matches the encoder's state. This enables decoders to remain simple and understand a wide variety of encoders.

As two consecutive sets of header fields often have header fields in common, each set of header fields is coded as a difference from the previous set of header fields. The goal is to only encode the changes (header fields present in one of the set and not in the other) between the two sets of header fields.

Examples illustrating the use of these different mechanisms to represent header fields are available in Appendix E.

3.1. Encoding Concepts

The encoding and decoding of header fields relies on some components and concepts:

3.1.1. Encoding Context

The set of mutable structures used within an encoding context include a header table and a reference set. Everything else is either immutable or conceptual.

Using HTTP, messages are exchanged between a client and a server in both direction. To keep the encoding of header fields in each direction independent from the other direction, there is one encoding context for each direction.

The header fields contained in a PUSH_PROMISE frame sent by a server to a client are encoded within the same context as the header fields contained in the HEADERS frame corresponding to a response sent from the server to the client.

3.1.2.

A header table consists of a list of header fields maintained in first-in, first-out order. The first and newest entry in a header table is always at index 0, and the oldest entry of a header table is at the index len(header table)-1.

There is typically no need for the header table to contain duplicate entries. However, duplicate entries MUST NOT be treated as an error by a decoder.

The encoder decides how to update the header table and as such can control how much memory is used by the header table. To limit the memory requirements on the decoder side, the header table size is strictly bounded (see Section 3.3.1).

The header table is updated during the processing of a set of header field representations (see header field representation processing [header.representation.processing].

3.1.3. Reference Set

A reference set is an unordered set of references to entries either within the header table or the static table.

The reference set is updated during the processing of a set of header field representations (see header field representation processing [header.representation.processing].

The reference set enables differential encoding, whereby only differences between the previous header set and the current header set need to be encoded.

When an entry is evicted from the header table, if it was referenced from the reference set, its reference is removed from the reference set.

3.1.4.

3.1.5.

The emission of a header field is the process of passing that header field to the application, so that the application can process and react to header field data.

By emitting header fields instead of emitting header sets, the decoder can be implemented in a streaming way, and as such must only keep in memory the header table and the reference set. This bounds the amount of memory used by the decoder, even in presence of a very large set of header fields. The management of memory for handling very large sets of header fields can therefore be deferred to the application.

When a header field is a NULL-separated list of values, each value within the list MAY be emitted separately, with the same header field name, and the order of emission MUST be the order of appearance in the list.

3.2.

The processing of a header block to obtain a header set is defined in this section. To ensure that the decoding will successfully produce a header set, a decoder MUST obey the following rules.

3.2.1.

All the header field representations contained in a header block are processed in the order in which they are presented, as specified below.

An indexed representation corresponding to an entry present in the reference set entails the following actions:

An indexed representation corresponding to an entry not present in the reference set entails the following actions:

A literal representation that is not added to the header table entails the following action:

A literal representation that is added to the header table entails the following actions:

3.2.2. Reference Set Emission

Once all the representations contained in a header block have been processed, the header fields referenced in the reference set which have not previously been emitted during this processing are emitted.

3.2.3.

Once all of the header field representations have been processed, and the remaining items in the reference set have been emitted, the header set is complete.

3.3.

3.3.1. Maximum Table Size

To limit the memory requirements on the decoder side, the size of the the header table is bounded. The size of the header table MUST stay lower than or equal to the value of the HTTP/2.0 setting SETTINGS_HEADER_TABLE_SIZE (see [HTTP2]).

The size of an entry is the sum of its name's length in bytes (as defined in Section 4.1.2), of its value's length in bytes (Section 4.1.2) and of 32 bytes.

The lengths are measured on the non-encoded entry name and entry value (for the case when a Huffman encoding is used to transmit string values).

The 32 bytes are an accounting for the entry structure overhead. For example, an entry structure using two 64-bits pointers to reference the name and the value and the entry, and two 64-bits integer for counting the number of references to these name and value would use 32 bytes.

3.3.2. Entry Eviction When Header Table Size Changes

Whenever an entry is evicted from the header table, any reference to that entry contained by the reference set is removed.

Whenever SETTINGS_HEADER_TABLE_SIZE is made smaller, entries are evicted from the end of the header table until the size of the header table is less than or equal to SETTINGS_HEADER_TABLE_SIZE.

The eviction of an entry from the header table causes the index of the entries in the static table to be reduced by one.

3.3.3. Entry Eviction when Adding New Entries

Whenever a new entry is to be added to the table, any name referenced by the representation is cached, and then entries are evicted from the end of the header table until the size of the header table is less than or equal to SETTINGS_HEADER_TABLE_SIZE - new entry size, or until the table is empty.

If the size of the new entry is less than or equal to SETTINGS_HEADER_TABLE_SIZE, that entry is added to the table. It is not an error to attempt to add an entry that is larger than SETTINGS_HEADER_TABLE_SIZE.

4. Detailed Format

4.1. Low-level representations

4.1.1. Integer representation

Integers are used to represent name indexes, pair indexes or string lengths. To allow for optimized processing, an integer representation always finishes at the end of a byte.

An integer is represented in two parts: a prefix that fills the current byte and an optional list of bytes that are used if the integer value does not fit within the prefix. The number of bits of the prefix (called N) is a parameter of the integer representation.

The N-bit prefix allows filling the current byte. If the value is small enough (strictly less than 2unsigned variable length integer representation. N is always between 1 and 8 bits. An integer starting at a byte-boundary will have an 8-bit prefix.

This integer representation allows for values of indefinite size. It is also possible for an encoder to send a large number of zero values, which can waste bytes and could be used to overflow integer values. Excessively large integer encodings - in value or octet length - MUST be treated as a decoding error. Different limits can be set for each of the different uses of integers, based on implementation constraints.

4.1.1.1. Example 1: Encoding 10 using a 5-bit prefix

4.1.1.2. Example 2: Encoding 1337 using a 5-bit prefix

4.1.2. String Literal Representation

Header field names and header field values are encoded as sequences of bytes. A header field name or a header field value is encoded in three parts:

Padding is necessary when doing huffman encoding to ensure that the remaining bits between the actual end of the data and the next byte boundary are not misinterpreted as part of the input data.

When padding for huffman encoding, use the bits from the EOS (end-of-string) entry in the Huffman table, starting with the MSB. This entry is guaranteed to be at least 8 bits long.

The EOS symbol is represented with value 256, and is used solely to signal the end of the huffman-encoded key data or the end of the huffman-encoded value data. Given that only between 0-7 bits of the EOS symbol is included in any huffman-encoded string, and given that the EOS symbol is at least 8 bits long, it is expected that it should never be successfully decoded.

4.2.

An indexed header field representation either identifies an entry in the header table or static table. The specified entry is emitted and a reference to that entry is added to the reference set if it is not currently in the reference set. If it is present in the reference set then the reference is removed and the entry is not emitted.

This representation starts with the '1' 1-bit pattern, followed by the index of the matching pair, represented as an integer with a 7-bit prefix.

4.3.

Literal header field representations contain a literal header field value. Header field names are either provided as a literal or by reference to an existing header table or static table entry.

Literal representations all result in the emission of a header field when decoded.

4.3.1.

A literal header field without indexing causes the emission of a header field without altering the header table.

If the header field name matches the header field name of a (name, value) pair stored in the Header Table or Static Table, the index of that entry, increased by one (index + 1), is represented as an integer with a 6-bit prefix. Note that if the index is strictly below 63, only one byte is used for this representation.

If the header field name does not match a header field name entry, the value 0 is represented on 6 bits followed by the header field name (Section 4.1.2).

The header field name representation is followed by the header field value represented as a literal string as described in Section 4.1.2.

4.3.2.

A literal header field with incremental indexing adds a new entry to the header table.

If the header field name matches the header field name of a (name, value) pair stored in the header table or static table, the index of the pair increased by one (index + 1) is represented as an integer with a 6-bit prefix.

If the header field name does not match a header field name entry, the value 0 is represented on 6 bits followed by the header field name (Section 4.1.2).

The header field name representation is followed by the header field value represented as a literal string as described in Section 4.1.2.

5. Security Considerations

This compressor exists to solve security issues present in stream compressors such as DEFLATE whereby the compression context can be efficiently probed to reveal secrets. A conformant implementation of this specification should be fairly safe against that kind of attack, as the reaping of any information from the compression context requires more work than guessing and verifying the plaintext data directly with the server. As with any secret, however, the longer the length of the secret, the more difficult the secret is to guess. It is inadvisable to have short cookies that are relied upon to remain secret for any duration of time.

A proper security-conscious implementation will also need to prevent timing attacks by ensuring that the amount of time it takes to do string comparisons is always a function of the total length of the strings, and not a function of the number of matched characters.

A decoder needs to ensure that larger values or encodings of integers do not permit exploitation. Decoders MUST limit the size of integers, both in value and encoded length, that it accepts (see Section 4.1.1).

Another common security problem is when the remote endpoint successfully causes the local endpoint to exhaust its memory. This compressor attempts to deal with the most obvious ways that this could occur by limiting both the peak and the steady-state amount of memory consumed in the compressor state, by providing ways for the application to consume/flush the emitted header fields in small chunks, and by considering overhead in the state size calculation. Implementors must still be careful in the creation of APIs to an implementation of this compressor by ensuring that header field keys and values are either emitted as a stream, or that the compression implementation have a limit on the maximum size of a key or value. Failure to implement these kinds of safeguards may still result in a scenario where the local endpoint exhausts its memory.

6. References

6.1. Normative References

6.2. Informative References

Appendix A. Change Log (to be removed by RFC Editor before publication

A.1. Since draft-ietf-httpbis-header-compression-03

A.2. Since draft-ietf-httpbis-header-compression-02

A.3. Since draft-ietf-httpbis-header-compression-01

A.4. Since draft-ietf-httpbis-header-compression-01

Appendix B. Static Table

The static table consists of an unchangable ordered list of (name, value) pairs. The first entry in the table is always represented by the index len(header table), and the last entry in the table is represented by the index len(header table)+len(static table)-1.

The following table lists the pre-defined header fields that make-up the static header table.

Static Table Entries
Index	Header Name	Header Value
0	:authority
1	:method	GET
2	:method	POST
3	:path	/
4	:path	/index.html
5	:scheme	http
6	:scheme	https
7	:status	200
8	:status	500
9	:status	404
10	:status	403
11	:status	400
12	:status	401
13	accept-charset
14	accept-encoding
15	accept-language
16	accept-ranges
17	accept
18	access-control-allow-origin
19	age
20	allow
21	authorization
22	cache-control
23	content-disposition
24	content-encoding
25	content-language
26	content-length
27	content-location
28	content-range
29	content-type
30	cookie
31	date
32	etag
33	expect
34	expires
35	from
36	if-match
37	if-modified-since
38	if-none-match
39	if-range
40	if-unmodified-since
41	last-modified
42	link
43	location
44	max-forwards
45	proxy-authenticate
46	proxy-authorization
47	range
48	referer
49	refresh
50	retry-after
51	server
52	set-cookie
53	strict-transport-security
54	transfer-encoding
55	user-agent
56	vary
57	via
58	www-authenticate

The table give the index of each entry in the static table. The full index of each entry, to be used for encoding a reference to this entry, is computed by adding the number of entries in the header table to this index.

Appendix C. Huffman Codes For Requests

The following Huffman codes are used when encoding string literals in the client to server direction.

             aligned                                  aligned
              to                            len        to     len
              MSB                            in        LSB     in
       sym    as bits                       bits      as hex  bits
      (  0) |11111111|11111111|11110111|010 [27]      7ffffba [27]
      (  1) |11111111|11111111|11110111|011 [27]      7ffffbb [27]
      (  2) |11111111|11111111|11110111|100 [27]      7ffffbc [27]
      (  3) |11111111|11111111|11110111|101 [27]      7ffffbd [27]
      (  4) |11111111|11111111|11110111|110 [27]      7ffffbe [27]
      (  5) |11111111|11111111|11110111|111 [27]      7ffffbf [27]
      (  6) |11111111|11111111|11111000|000 [27]      7ffffc0 [27]
      (  7) |11111111|11111111|11111000|001 [27]      7ffffc1 [27]
      (  8) |11111111|11111111|11111000|010 [27]      7ffffc2 [27]
      (  9) |11111111|11111111|11111000|011 [27]      7ffffc3 [27]
      ( 10) |11111111|11111111|11111000|100 [27]      7ffffc4 [27]
      ( 11) |11111111|11111111|11111000|101 [27]      7ffffc5 [27]
      ( 12) |11111111|11111111|11111000|110 [27]      7ffffc6 [27]
      ( 13) |11111111|11111111|11111000|111 [27]      7ffffc7 [27]
      ( 14) |11111111|11111111|11111001|000 [27]      7ffffc8 [27]
      ( 15) |11111111|11111111|11111001|001 [27]      7ffffc9 [27]
      ( 16) |11111111|11111111|11111001|010 [27]      7ffffca [27]
      ( 17) |11111111|11111111|11111001|011 [27]      7ffffcb [27]
      ( 18) |11111111|11111111|11111001|100 [27]      7ffffcc [27]
      ( 19) |11111111|11111111|11111001|101 [27]      7ffffcd [27]
      ( 20) |11111111|11111111|11111001|110 [27]      7ffffce [27]
      ( 21) |11111111|11111111|11111001|111 [27]      7ffffcf [27]
      ( 22) |11111111|11111111|11111010|000 [27]      7ffffd0 [27]
      ( 23) |11111111|11111111|11111010|001 [27]      7ffffd1 [27]
      ( 24) |11111111|11111111|11111010|010 [27]      7ffffd2 [27]
      ( 25) |11111111|11111111|11111010|011 [27]      7ffffd3 [27]
      ( 26) |11111111|11111111|11111010|100 [27]      7ffffd4 [27]
      ( 27) |11111111|11111111|11111010|101 [27]      7ffffd5 [27]
      ( 28) |11111111|11111111|11111010|110 [27]      7ffffd6 [27]
      ( 29) |11111111|11111111|11111010|111 [27]      7ffffd7 [27]
      ( 30) |11111111|11111111|11111011|000 [27]      7ffffd8 [27]
      ( 31) |11111111|11111111|11111011|001 [27]      7ffffd9 [27]
  ' ' ( 32) |11101000| [8]                                  e8 [8]
  '!' ( 33) |11111111|1100 [12]                           ffc [12]
  '"' ( 34) |11111111|111010 [14]                        3ffa [14]
  '#' ( 35) |11111111|1111100 [15]                       7ffc [15]
  '$' ( 36) |11111111|1111101 [15]                       7ffd [15]
  '%' ( 37) |100100 [6]                                     24 [6]
  '&' ( 38) |1101110 [7]                                    6e [7]
  ''' ( 39) |11111111|1111110 [15]                       7ffe [15]
  '(' ( 40) |11111111|010 [11]                            7fa [11]
  ')' ( 41) |11111111|011 [11]                            7fb [11]
  '*' ( 42) |11111110|10 [10]                             3fa [10]
  '+' ( 43) |11111111|100 [11]                            7fc [11]
  ',' ( 44) |11101001| [8]                                  e9 [8]
  '-' ( 45) |100101 [6]                                     25 [6]
  '.' ( 46) |00100 [5]                                       4 [5]
  '/' ( 47) |0000 [4]                                        0 [4]
  '0' ( 48) |00101 [5]                                       5 [5]
  '1' ( 49) |00110 [5]                                       6 [5]
  '2' ( 50) |00111 [5]                                       7 [5]
  '3' ( 51) |100110 [6]                                     26 [6]
  '4' ( 52) |100111 [6]                                     27 [6]
  '5' ( 53) |101000 [6]                                     28 [6]
  '6' ( 54) |101001 [6]                                     29 [6]
  '7' ( 55) |101010 [6]                                     2a [6]
  '8' ( 56) |101011 [6]                                     2b [6]
  '9' ( 57) |101100 [6]                                     2c [6]
  ':' ( 58) |11110110|0 [9]                                1ec [9]
  ';' ( 59) |11101010| [8]                                  ea [8]
  '<' ( 60) |11111111|11111111|10 [18]                  3fffe [18]
  '=' ( 61) |101101 [6]                                     2d [6]
  '>' ( 62) |11111111|11111110|0 [17]                   1fffc [17]
  '?' ( 63) |11110110|1 [9]                                1ed [9]
  '@' ( 64) |11111111|111011 [14]                        3ffb [14]
  'A' ( 65) |1101111 [7]                                    6f [7]
  'B' ( 66) |11101011| [8]                                  eb [8]
  'C' ( 67) |11101100| [8]                                  ec [8]
  'D' ( 68) |11101101| [8]                                  ed [8]
  'E' ( 69) |11101110| [8]                                  ee [8]
  'F' ( 70) |1110000 [7]                                    70 [7]
  'G' ( 71) |11110111|0 [9]                                1ee [9]
  'H' ( 72) |11110111|1 [9]                                1ef [9]
  'I' ( 73) |11111000|0 [9]                                1f0 [9]
  'J' ( 74) |11111000|1 [9]                                1f1 [9]
  'K' ( 75) |11111110|11 [10]                             3fb [10]
  'L' ( 76) |11111001|0 [9]                                1f2 [9]
  'M' ( 77) |11101111| [8]                                  ef [8]
  'N' ( 78) |11111001|1 [9]                                1f3 [9]
  'O' ( 79) |11111010|0 [9]                                1f4 [9]
  'P' ( 80) |11111010|1 [9]                                1f5 [9]
  'Q' ( 81) |11111011|0 [9]                                1f6 [9]
  'R' ( 82) |11111011|1 [9]                                1f7 [9]
  'S' ( 83) |11110000| [8]                                  f0 [8]
  'T' ( 84) |11110001| [8]                                  f1 [8]
  'U' ( 85) |11111100|0 [9]                                1f8 [9]
  'V' ( 86) |11111100|1 [9]                                1f9 [9]
  'W' ( 87) |11111101|0 [9]                                1fa [9]
  'X' ( 88) |11111101|1 [9]                                1fb [9]
  'Y' ( 89) |11111110|0 [9]                                1fc [9]
  'Z' ( 90) |11111111|00 [10]                             3fc [10]
  '[' ( 91) |11111111|111100 [14]                        3ffc [14]
  '\' ( 92) |11111111|11111111|11111011|010 [27]      7ffffda [27]
  ']' ( 93) |11111111|11100 [13]                         1ffc [13]
  '^' ( 94) |11111111|111101 [14]                        3ffd [14]
  '_' ( 95) |101110 [6]                                     2e [6]
  '`' ( 96) |11111111|11111111|110 [19]                 7fffe [19]
  'a' ( 97) |01000 [5]                                       8 [5]
  'b' ( 98) |101111 [6]                                     2f [6]
  'c' ( 99) |01001 [5]                                       9 [5]
  'd' (100) |110000 [6]                                     30 [6]
  'e' (101) |0001 [4]                                        1 [4]
  'f' (102) |110001 [6]                                     31 [6]
  'g' (103) |110010 [6]                                     32 [6]
  'h' (104) |110011 [6]                                     33 [6]
  'i' (105) |01010 [5]                                       a [5]
  'j' (106) |1110001 [7]                                    71 [7]
  'k' (107) |1110010 [7]                                    72 [7]
  'l' (108) |01011 [5]                                       b [5]
  'm' (109) |110100 [6]                                     34 [6]
  'n' (110) |01100 [5]                                       c [5]
  'o' (111) |01101 [5]                                       d [5]
  'p' (112) |01110 [5]                                       e [5]
  'q' (113) |11110010| [8]                                  f2 [8]
  'r' (114) |01111 [5]                                       f [5]
  's' (115) |10000 [5]                                      10 [5]
  't' (116) |10001 [5]                                      11 [5]
  'u' (117) |110101 [6]                                     35 [6]
  'v' (118) |1110011 [7]                                    73 [7]
  'w' (119) |110110 [6]                                     36 [6]
  'x' (120) |11110011| [8]                                  f3 [8]
  'y' (121) |11110100| [8]                                  f4 [8]
  'z' (122) |11110101| [8]                                  f5 [8]
  '{' (123) |11111111|11111110|1 [17]                   1fffd [17]
  '|' (124) |11111111|101 [11]                            7fd [11]
  '}' (125) |11111111|11111111|0 [17]                   1fffe [17]
  '~' (126) |11111111|1101 [12]                           ffd [12]
      (127) |11111111|11111111|11111011|011 [27]      7ffffdb [27]
      (128) |11111111|11111111|11111011|100 [27]      7ffffdc [27]
      (129) |11111111|11111111|11111011|101 [27]      7ffffdd [27]
      (130) |11111111|11111111|11111011|110 [27]      7ffffde [27]
      (131) |11111111|11111111|11111011|111 [27]      7ffffdf [27]
      (132) |11111111|11111111|11111100|000 [27]      7ffffe0 [27]
      (133) |11111111|11111111|11111100|001 [27]      7ffffe1 [27]
      (134) |11111111|11111111|11111100|010 [27]      7ffffe2 [27]
      (135) |11111111|11111111|11111100|011 [27]      7ffffe3 [27]
      (136) |11111111|11111111|11111100|100 [27]      7ffffe4 [27]
      (137) |11111111|11111111|11111100|101 [27]      7ffffe5 [27]
      (138) |11111111|11111111|11111100|110 [27]      7ffffe6 [27]
      (139) |11111111|11111111|11111100|111 [27]      7ffffe7 [27]
      (140) |11111111|11111111|11111101|000 [27]      7ffffe8 [27]
      (141) |11111111|11111111|11111101|001 [27]      7ffffe9 [27]
      (142) |11111111|11111111|11111101|010 [27]      7ffffea [27]
      (143) |11111111|11111111|11111101|011 [27]      7ffffeb [27]
      (144) |11111111|11111111|11111101|100 [27]      7ffffec [27]
      (145) |11111111|11111111|11111101|101 [27]      7ffffed [27]
      (146) |11111111|11111111|11111101|110 [27]      7ffffee [27]
      (147) |11111111|11111111|11111101|111 [27]      7ffffef [27]
      (148) |11111111|11111111|11111110|000 [27]      7fffff0 [27]
      (149) |11111111|11111111|11111110|001 [27]      7fffff1 [27]
      (150) |11111111|11111111|11111110|010 [27]      7fffff2 [27]
      (151) |11111111|11111111|11111110|011 [27]      7fffff3 [27]
      (152) |11111111|11111111|11111110|100 [27]      7fffff4 [27]
      (153) |11111111|11111111|11111110|101 [27]      7fffff5 [27]
      (154) |11111111|11111111|11111110|110 [27]      7fffff6 [27]
      (155) |11111111|11111111|11111110|111 [27]      7fffff7 [27]
      (156) |11111111|11111111|11111111|000 [27]      7fffff8 [27]
      (157) |11111111|11111111|11111111|001 [27]      7fffff9 [27]
      (158) |11111111|11111111|11111111|010 [27]      7fffffa [27]
      (159) |11111111|11111111|11111111|011 [27]      7fffffb [27]
      (160) |11111111|11111111|11111111|100 [27]      7fffffc [27]
      (161) |11111111|11111111|11111111|101 [27]      7fffffd [27]
      (162) |11111111|11111111|11111111|110 [27]      7fffffe [27]
      (163) |11111111|11111111|11111111|111 [27]      7ffffff [27]
      (164) |11111111|11111111|11100000|00 [26]       3ffff80 [26]
      (165) |11111111|11111111|11100000|01 [26]       3ffff81 [26]
      (166) |11111111|11111111|11100000|10 [26]       3ffff82 [26]
      (167) |11111111|11111111|11100000|11 [26]       3ffff83 [26]
      (168) |11111111|11111111|11100001|00 [26]       3ffff84 [26]
      (169) |11111111|11111111|11100001|01 [26]       3ffff85 [26]
      (170) |11111111|11111111|11100001|10 [26]       3ffff86 [26]
      (171) |11111111|11111111|11100001|11 [26]       3ffff87 [26]
      (172) |11111111|11111111|11100010|00 [26]       3ffff88 [26]
      (173) |11111111|11111111|11100010|01 [26]       3ffff89 [26]
      (174) |11111111|11111111|11100010|10 [26]       3ffff8a [26]
      (175) |11111111|11111111|11100010|11 [26]       3ffff8b [26]
      (176) |11111111|11111111|11100011|00 [26]       3ffff8c [26]
      (177) |11111111|11111111|11100011|01 [26]       3ffff8d [26]
      (178) |11111111|11111111|11100011|10 [26]       3ffff8e [26]
      (179) |11111111|11111111|11100011|11 [26]       3ffff8f [26]
      (180) |11111111|11111111|11100100|00 [26]       3ffff90 [26]
      (181) |11111111|11111111|11100100|01 [26]       3ffff91 [26]
      (182) |11111111|11111111|11100100|10 [26]       3ffff92 [26]
      (183) |11111111|11111111|11100100|11 [26]       3ffff93 [26]
      (184) |11111111|11111111|11100101|00 [26]       3ffff94 [26]
      (185) |11111111|11111111|11100101|01 [26]       3ffff95 [26]
      (186) |11111111|11111111|11100101|10 [26]       3ffff96 [26]
      (187) |11111111|11111111|11100101|11 [26]       3ffff97 [26]
      (188) |11111111|11111111|11100110|00 [26]       3ffff98 [26]
      (189) |11111111|11111111|11100110|01 [26]       3ffff99 [26]
      (190) |11111111|11111111|11100110|10 [26]       3ffff9a [26]
      (191) |11111111|11111111|11100110|11 [26]       3ffff9b [26]
      (192) |11111111|11111111|11100111|00 [26]       3ffff9c [26]
      (193) |11111111|11111111|11100111|01 [26]       3ffff9d [26]
      (194) |11111111|11111111|11100111|10 [26]       3ffff9e [26]
      (195) |11111111|11111111|11100111|11 [26]       3ffff9f [26]
      (196) |11111111|11111111|11101000|00 [26]       3ffffa0 [26]
      (197) |11111111|11111111|11101000|01 [26]       3ffffa1 [26]
      (198) |11111111|11111111|11101000|10 [26]       3ffffa2 [26]
      (199) |11111111|11111111|11101000|11 [26]       3ffffa3 [26]
      (200) |11111111|11111111|11101001|00 [26]       3ffffa4 [26]
      (201) |11111111|11111111|11101001|01 [26]       3ffffa5 [26]
      (202) |11111111|11111111|11101001|10 [26]       3ffffa6 [26]
      (203) |11111111|11111111|11101001|11 [26]       3ffffa7 [26]
      (204) |11111111|11111111|11101010|00 [26]       3ffffa8 [26]
      (205) |11111111|11111111|11101010|01 [26]       3ffffa9 [26]
      (206) |11111111|11111111|11101010|10 [26]       3ffffaa [26]
      (207) |11111111|11111111|11101010|11 [26]       3ffffab [26]
      (208) |11111111|11111111|11101011|00 [26]       3ffffac [26]
      (209) |11111111|11111111|11101011|01 [26]       3ffffad [26]
      (210) |11111111|11111111|11101011|10 [26]       3ffffae [26]
      (211) |11111111|11111111|11101011|11 [26]       3ffffaf [26]
      (212) |11111111|11111111|11101100|00 [26]       3ffffb0 [26]
      (213) |11111111|11111111|11101100|01 [26]       3ffffb1 [26]
      (214) |11111111|11111111|11101100|10 [26]       3ffffb2 [26]
      (215) |11111111|11111111|11101100|11 [26]       3ffffb3 [26]
      (216) |11111111|11111111|11101101|00 [26]       3ffffb4 [26]
      (217) |11111111|11111111|11101101|01 [26]       3ffffb5 [26]
      (218) |11111111|11111111|11101101|10 [26]       3ffffb6 [26]
      (219) |11111111|11111111|11101101|11 [26]       3ffffb7 [26]
      (220) |11111111|11111111|11101110|00 [26]       3ffffb8 [26]
      (221) |11111111|11111111|11101110|01 [26]       3ffffb9 [26]
      (222) |11111111|11111111|11101110|10 [26]       3ffffba [26]
      (223) |11111111|11111111|11101110|11 [26]       3ffffbb [26]
      (224) |11111111|11111111|11101111|00 [26]       3ffffbc [26]
      (225) |11111111|11111111|11101111|01 [26]       3ffffbd [26]
      (226) |11111111|11111111|11101111|10 [26]       3ffffbe [26]
      (227) |11111111|11111111|11101111|11 [26]       3ffffbf [26]
      (228) |11111111|11111111|11110000|00 [26]       3ffffc0 [26]
      (229) |11111111|11111111|11110000|01 [26]       3ffffc1 [26]
      (230) |11111111|11111111|11110000|10 [26]       3ffffc2 [26]
      (231) |11111111|11111111|11110000|11 [26]       3ffffc3 [26]
      (232) |11111111|11111111|11110001|00 [26]       3ffffc4 [26]
      (233) |11111111|11111111|11110001|01 [26]       3ffffc5 [26]
      (234) |11111111|11111111|11110001|10 [26]       3ffffc6 [26]
      (235) |11111111|11111111|11110001|11 [26]       3ffffc7 [26]
      (236) |11111111|11111111|11110010|00 [26]       3ffffc8 [26]
      (237) |11111111|11111111|11110010|01 [26]       3ffffc9 [26]
      (238) |11111111|11111111|11110010|10 [26]       3ffffca [26]
      (239) |11111111|11111111|11110010|11 [26]       3ffffcb [26]
      (240) |11111111|11111111|11110011|00 [26]       3ffffcc [26]
      (241) |11111111|11111111|11110011|01 [26]       3ffffcd [26]
      (242) |11111111|11111111|11110011|10 [26]       3ffffce [26]
      (243) |11111111|11111111|11110011|11 [26]       3ffffcf [26]
      (244) |11111111|11111111|11110100|00 [26]       3ffffd0 [26]
      (245) |11111111|11111111|11110100|01 [26]       3ffffd1 [26]
      (246) |11111111|11111111|11110100|10 [26]       3ffffd2 [26]
      (247) |11111111|11111111|11110100|11 [26]       3ffffd3 [26]
      (248) |11111111|11111111|11110101|00 [26]       3ffffd4 [26]
      (249) |11111111|11111111|11110101|01 [26]       3ffffd5 [26]
      (250) |11111111|11111111|11110101|10 [26]       3ffffd6 [26]
      (251) |11111111|11111111|11110101|11 [26]       3ffffd7 [26]
      (252) |11111111|11111111|11110110|00 [26]       3ffffd8 [26]
      (253) |11111111|11111111|11110110|01 [26]       3ffffd9 [26]
      (254) |11111111|11111111|11110110|10 [26]       3ffffda [26]
      (255) |11111111|11111111|11110110|11 [26]       3ffffdb [26]
  EOS (256) |11111111|11111111|11110111|00 [26]       3ffffdc [26]

Appendix D. Huffman Codes for Responses

The following Huffman codes are used when encoding string literals in the server to client direction.

             aligned                                  aligned
              to                           len         to     len
              MSB                           in         LSB     in
       sym    as bits                      bits       as hex  bits
      (  0) |11111111|11111111|11011110|0 [25]        1ffffbc [25]
      (  1) |11111111|11111111|11011110|1 [25]        1ffffbd [25]
      (  2) |11111111|11111111|11011111|0 [25]        1ffffbe [25]
      (  3) |11111111|11111111|11011111|1 [25]        1ffffbf [25]
      (  4) |11111111|11111111|11100000|0 [25]        1ffffc0 [25]
      (  5) |11111111|11111111|11100000|1 [25]        1ffffc1 [25]
      (  6) |11111111|11111111|11100001|0 [25]        1ffffc2 [25]
      (  7) |11111111|11111111|11100001|1 [25]        1ffffc3 [25]
      (  8) |11111111|11111111|11100010|0 [25]        1ffffc4 [25]
      (  9) |11111111|11111111|11100010|1 [25]        1ffffc5 [25]
      ( 10) |11111111|11111111|11100011|0 [25]        1ffffc6 [25]
      ( 11) |11111111|11111111|11100011|1 [25]        1ffffc7 [25]
      ( 12) |11111111|11111111|11100100|0 [25]        1ffffc8 [25]
      ( 13) |11111111|11111111|11100100|1 [25]        1ffffc9 [25]
      ( 14) |11111111|11111111|11100101|0 [25]        1ffffca [25]
      ( 15) |11111111|11111111|11100101|1 [25]        1ffffcb [25]
      ( 16) |11111111|11111111|11100110|0 [25]        1ffffcc [25]
      ( 17) |11111111|11111111|11100110|1 [25]        1ffffcd [25]
      ( 18) |11111111|11111111|11100111|0 [25]        1ffffce [25]
      ( 19) |11111111|11111111|11100111|1 [25]        1ffffcf [25]
      ( 20) |11111111|11111111|11101000|0 [25]        1ffffd0 [25]
      ( 21) |11111111|11111111|11101000|1 [25]        1ffffd1 [25]
      ( 22) |11111111|11111111|11101001|0 [25]        1ffffd2 [25]
      ( 23) |11111111|11111111|11101001|1 [25]        1ffffd3 [25]
      ( 24) |11111111|11111111|11101010|0 [25]        1ffffd4 [25]
      ( 25) |11111111|11111111|11101010|1 [25]        1ffffd5 [25]
      ( 26) |11111111|11111111|11101011|0 [25]        1ffffd6 [25]
      ( 27) |11111111|11111111|11101011|1 [25]        1ffffd7 [25]
      ( 28) |11111111|11111111|11101100|0 [25]        1ffffd8 [25]
      ( 29) |11111111|11111111|11101100|1 [25]        1ffffd9 [25]
      ( 30) |11111111|11111111|11101101|0 [25]        1ffffda [25]
      ( 31) |11111111|11111111|11101101|1 [25]        1ffffdb [25]
  ' ' ( 32) |0000 [4]                                        0 [4]
  '!' ( 33) |11111111|1010 [12]                           ffa [12]
  '"' ( 34) |1101010 [7]                                    6a [7]
  '#' ( 35) |11111111|11010 [13]                         1ffa [13]
  '$' ( 36) |11111111|111100 [14]                        3ffc [14]
  '%' ( 37) |11110110|0 [9]                                1ec [9]
  '&' ( 38) |11111110|00 [10]                             3f8 [10]
  ''' ( 39) |11111111|11011 [13]                         1ffb [13]
  '(' ( 40) |11110110|1 [9]                                1ed [9]
  ')' ( 41) |11110111|0 [9]                                1ee [9]
  '*' ( 42) |11111111|1011 [12]                           ffb [12]
  '+' ( 43) |11111111|010 [11]                            7fa [11]
  ',' ( 44) |100010 [6]                                     22 [6]
  '-' ( 45) |100011 [6]                                     23 [6]
  '.' ( 46) |100100 [6]                                     24 [6]
  '/' ( 47) |1101011 [7]                                    6b [7]
  '0' ( 48) |0001 [4]                                        1 [4]
  '1' ( 49) |0010 [4]                                        2 [4]
  '2' ( 50) |0011 [4]                                        3 [4]
  '3' ( 51) |01000 [5]                                       8 [5]
  '4' ( 52) |01001 [5]                                       9 [5]
  '5' ( 53) |01010 [5]                                       a [5]
  '6' ( 54) |100101 [6]                                     25 [6]
  '7' ( 55) |100110 [6]                                     26 [6]
  '8' ( 56) |01011 [5]                                       b [5]
  '9' ( 57) |01100 [5]                                       c [5]
  ':' ( 58) |01101 [5]                                       d [5]
  ';' ( 59) |11110111|1 [9]                                1ef [9]
  '<' ( 60) |11111111|11111010| [16]                     fffa [16]
  '=' ( 61) |1101100 [7]                                    6c [7]
  '>' ( 62) |11111111|11100 [13]                         1ffc [13]
  '?' ( 63) |11111111|1100 [12]                           ffc [12]
  '@' ( 64) |11111111|11111011| [16]                     fffb [16]
  'A' ( 65) |1101101 [7]                                    6d [7]
  'B' ( 66) |11101010| [8]                                  ea [8]
  'C' ( 67) |11101011| [8]                                  eb [8]
  'D' ( 68) |11101100| [8]                                  ec [8]
  'E' ( 69) |11101101| [8]                                  ed [8]
  'F' ( 70) |11101110| [8]                                  ee [8]
  'G' ( 71) |100111 [6]                                     27 [6]
  'H' ( 72) |11111000|0 [9]                                1f0 [9]
  'I' ( 73) |11101111| [8]                                  ef [8]
  'J' ( 74) |11110000| [8]                                  f0 [8]
  'K' ( 75) |11111110|01 [10]                             3f9 [10]
  'L' ( 76) |11111000|1 [9]                                1f1 [9]
  'M' ( 77) |101000 [6]                                     28 [6]
  'N' ( 78) |11110001| [8]                                  f1 [8]
  'O' ( 79) |11110010| [8]                                  f2 [8]
  'P' ( 80) |11111001|0 [9]                                1f2 [9]
  'Q' ( 81) |11111110|10 [10]                             3fa [10]
  'R' ( 82) |11111001|1 [9]                                1f3 [9]
  'S' ( 83) |101001 [6]                                     29 [6]
  'T' ( 84) |01110 [5]                                       e [5]
  'U' ( 85) |11111010|0 [9]                                1f4 [9]
  'V' ( 86) |11111010|1 [9]                                1f5 [9]
  'W' ( 87) |11110011| [8]                                  f3 [8]
  'X' ( 88) |11111110|11 [10]                             3fb [10]
  'Y' ( 89) |11111011|0 [9]                                1f6 [9]
  'Z' ( 90) |11111111|00 [10]                             3fc [10]
  '[' ( 91) |11111111|011 [11]                            7fb [11]
  '\' ( 92) |11111111|11101 [13]                         1ffd [13]
  ']' ( 93) |11111111|100 [11]                            7fc [11]
  '^' ( 94) |11111111|1111100 [15]                       7ffc [15]
  '_' ( 95) |11111011|1 [9]                                1f7 [9]
  '`' ( 96) |11111111|11111111|0 [17]                   1fffe [17]
  'a' ( 97) |01111 [5]                                       f [5]
  'b' ( 98) |1101110 [7]                                    6e [7]
  'c' ( 99) |101010 [6]                                     2a [6]
  'd' (100) |101011 [6]                                     2b [6]
  'e' (101) |10000 [5]                                      10 [5]
  'f' (102) |1101111 [7]                                    6f [7]
  'g' (103) |1110000 [7]                                    70 [7]
  'h' (104) |1110001 [7]                                    71 [7]
  'i' (105) |101100 [6]                                     2c [6]
  'j' (106) |11111100|0 [9]                                1f8 [9]
  'k' (107) |11111100|1 [9]                                1f9 [9]
  'l' (108) |1110010 [7]                                    72 [7]
  'm' (109) |101101 [6]                                     2d [6]
  'n' (110) |101110 [6]                                     2e [6]
  'o' (111) |101111 [6]                                     2f [6]
  'p' (112) |110000 [6]                                     30 [6]
  'q' (113) |11111101|0 [9]                                1fa [9]
  'r' (114) |110001 [6]                                     31 [6]
  's' (115) |110010 [6]                                     32 [6]
  't' (116) |110011 [6]                                     33 [6]
  'u' (117) |110100 [6]                                     34 [6]
  'v' (118) |1110011 [7]                                    73 [7]
  'w' (119) |11110100| [8]                                  f4 [8]
  'x' (120) |1110100 [7]                                    74 [7]
  'y' (121) |11110101| [8]                                  f5 [8]
  'z' (122) |11111101|1 [9]                                1fb [9]
  '{' (123) |11111111|11111100| [16]                     fffc [16]
  '|' (124) |11111111|111101 [14]                        3ffd [14]
  '}' (125) |11111111|11111101| [16]                     fffd [16]
  '~' (126) |11111111|11111110| [16]                     fffe [16]
      (127) |11111111|11111111|11101110|0 [25]        1ffffdc [25]
      (128) |11111111|11111111|11101110|1 [25]        1ffffdd [25]
      (129) |11111111|11111111|11101111|0 [25]        1ffffde [25]
      (130) |11111111|11111111|11101111|1 [25]        1ffffdf [25]
      (131) |11111111|11111111|11110000|0 [25]        1ffffe0 [25]
      (132) |11111111|11111111|11110000|1 [25]        1ffffe1 [25]
      (133) |11111111|11111111|11110001|0 [25]        1ffffe2 [25]
      (134) |11111111|11111111|11110001|1 [25]        1ffffe3 [25]
      (135) |11111111|11111111|11110010|0 [25]        1ffffe4 [25]
      (136) |11111111|11111111|11110010|1 [25]        1ffffe5 [25]
      (137) |11111111|11111111|11110011|0 [25]        1ffffe6 [25]
      (138) |11111111|11111111|11110011|1 [25]        1ffffe7 [25]
      (139) |11111111|11111111|11110100|0 [25]        1ffffe8 [25]
      (140) |11111111|11111111|11110100|1 [25]        1ffffe9 [25]
      (141) |11111111|11111111|11110101|0 [25]        1ffffea [25]
      (142) |11111111|11111111|11110101|1 [25]        1ffffeb [25]
      (143) |11111111|11111111|11110110|0 [25]        1ffffec [25]
      (144) |11111111|11111111|11110110|1 [25]        1ffffed [25]
      (145) |11111111|11111111|11110111|0 [25]        1ffffee [25]
      (146) |11111111|11111111|11110111|1 [25]        1ffffef [25]
      (147) |11111111|11111111|11111000|0 [25]        1fffff0 [25]
      (148) |11111111|11111111|11111000|1 [25]        1fffff1 [25]
      (149) |11111111|11111111|11111001|0 [25]        1fffff2 [25]
      (150) |11111111|11111111|11111001|1 [25]        1fffff3 [25]
      (151) |11111111|11111111|11111010|0 [25]        1fffff4 [25]
      (152) |11111111|11111111|11111010|1 [25]        1fffff5 [25]
      (153) |11111111|11111111|11111011|0 [25]        1fffff6 [25]
      (154) |11111111|11111111|11111011|1 [25]        1fffff7 [25]
      (155) |11111111|11111111|11111100|0 [25]        1fffff8 [25]
      (156) |11111111|11111111|11111100|1 [25]        1fffff9 [25]
      (157) |11111111|11111111|11111101|0 [25]        1fffffa [25]
      (158) |11111111|11111111|11111101|1 [25]        1fffffb [25]
      (159) |11111111|11111111|11111110|0 [25]        1fffffc [25]
      (160) |11111111|11111111|11111110|1 [25]        1fffffd [25]
      (161) |11111111|11111111|11111111|0 [25]        1fffffe [25]
      (162) |11111111|11111111|11111111|1 [25]        1ffffff [25]
      (163) |11111111|11111111|10000000| [24]          ffff80 [24]
      (164) |11111111|11111111|10000001| [24]          ffff81 [24]
      (165) |11111111|11111111|10000010| [24]          ffff82 [24]
      (166) |11111111|11111111|10000011| [24]          ffff83 [24]
      (167) |11111111|11111111|10000100| [24]          ffff84 [24]
      (168) |11111111|11111111|10000101| [24]          ffff85 [24]
      (169) |11111111|11111111|10000110| [24]          ffff86 [24]
      (170) |11111111|11111111|10000111| [24]          ffff87 [24]
      (171) |11111111|11111111|10001000| [24]          ffff88 [24]
      (172) |11111111|11111111|10001001| [24]          ffff89 [24]
      (173) |11111111|11111111|10001010| [24]          ffff8a [24]
      (174) |11111111|11111111|10001011| [24]          ffff8b [24]
      (175) |11111111|11111111|10001100| [24]          ffff8c [24]
      (176) |11111111|11111111|10001101| [24]          ffff8d [24]
      (177) |11111111|11111111|10001110| [24]          ffff8e [24]
      (178) |11111111|11111111|10001111| [24]          ffff8f [24]
      (179) |11111111|11111111|10010000| [24]          ffff90 [24]
      (180) |11111111|11111111|10010001| [24]          ffff91 [24]
      (181) |11111111|11111111|10010010| [24]          ffff92 [24]
      (182) |11111111|11111111|10010011| [24]          ffff93 [24]
      (183) |11111111|11111111|10010100| [24]          ffff94 [24]
      (184) |11111111|11111111|10010101| [24]          ffff95 [24]
      (185) |11111111|11111111|10010110| [24]          ffff96 [24]
      (186) |11111111|11111111|10010111| [24]          ffff97 [24]
      (187) |11111111|11111111|10011000| [24]          ffff98 [24]
      (188) |11111111|11111111|10011001| [24]          ffff99 [24]
      (189) |11111111|11111111|10011010| [24]          ffff9a [24]
      (190) |11111111|11111111|10011011| [24]          ffff9b [24]
      (191) |11111111|11111111|10011100| [24]          ffff9c [24]
      (192) |11111111|11111111|10011101| [24]          ffff9d [24]
      (193) |11111111|11111111|10011110| [24]          ffff9e [24]
      (194) |11111111|11111111|10011111| [24]          ffff9f [24]
      (195) |11111111|11111111|10100000| [24]          ffffa0 [24]
      (196) |11111111|11111111|10100001| [24]          ffffa1 [24]
      (197) |11111111|11111111|10100010| [24]          ffffa2 [24]
      (198) |11111111|11111111|10100011| [24]          ffffa3 [24]
      (199) |11111111|11111111|10100100| [24]          ffffa4 [24]
      (200) |11111111|11111111|10100101| [24]          ffffa5 [24]
      (201) |11111111|11111111|10100110| [24]          ffffa6 [24]
      (202) |11111111|11111111|10100111| [24]          ffffa7 [24]
      (203) |11111111|11111111|10101000| [24]          ffffa8 [24]
      (204) |11111111|11111111|10101001| [24]          ffffa9 [24]
      (205) |11111111|11111111|10101010| [24]          ffffaa [24]
      (206) |11111111|11111111|10101011| [24]          ffffab [24]
      (207) |11111111|11111111|10101100| [24]          ffffac [24]
      (208) |11111111|11111111|10101101| [24]          ffffad [24]
      (209) |11111111|11111111|10101110| [24]          ffffae [24]
      (210) |11111111|11111111|10101111| [24]          ffffaf [24]
      (211) |11111111|11111111|10110000| [24]          ffffb0 [24]
      (212) |11111111|11111111|10110001| [24]          ffffb1 [24]
      (213) |11111111|11111111|10110010| [24]          ffffb2 [24]
      (214) |11111111|11111111|10110011| [24]          ffffb3 [24]
      (215) |11111111|11111111|10110100| [24]          ffffb4 [24]
      (216) |11111111|11111111|10110101| [24]          ffffb5 [24]
      (217) |11111111|11111111|10110110| [24]          ffffb6 [24]
      (218) |11111111|11111111|10110111| [24]          ffffb7 [24]
      (219) |11111111|11111111|10111000| [24]          ffffb8 [24]
      (220) |11111111|11111111|10111001| [24]          ffffb9 [24]
      (221) |11111111|11111111|10111010| [24]          ffffba [24]
      (222) |11111111|11111111|10111011| [24]          ffffbb [24]
      (223) |11111111|11111111|10111100| [24]          ffffbc [24]
      (224) |11111111|11111111|10111101| [24]          ffffbd [24]
      (225) |11111111|11111111|10111110| [24]          ffffbe [24]
      (226) |11111111|11111111|10111111| [24]          ffffbf [24]
      (227) |11111111|11111111|11000000| [24]          ffffc0 [24]
      (228) |11111111|11111111|11000001| [24]          ffffc1 [24]
      (229) |11111111|11111111|11000010| [24]          ffffc2 [24]
      (230) |11111111|11111111|11000011| [24]          ffffc3 [24]
      (231) |11111111|11111111|11000100| [24]          ffffc4 [24]
      (232) |11111111|11111111|11000101| [24]          ffffc5 [24]
      (233) |11111111|11111111|11000110| [24]          ffffc6 [24]
      (234) |11111111|11111111|11000111| [24]          ffffc7 [24]
      (235) |11111111|11111111|11001000| [24]          ffffc8 [24]
      (236) |11111111|11111111|11001001| [24]          ffffc9 [24]
      (237) |11111111|11111111|11001010| [24]          ffffca [24]
      (238) |11111111|11111111|11001011| [24]          ffffcb [24]
      (239) |11111111|11111111|11001100| [24]          ffffcc [24]
      (240) |11111111|11111111|11001101| [24]          ffffcd [24]
      (241) |11111111|11111111|11001110| [24]          ffffce [24]
      (242) |11111111|11111111|11001111| [24]          ffffcf [24]
      (243) |11111111|11111111|11010000| [24]          ffffd0 [24]
      (244) |11111111|11111111|11010001| [24]          ffffd1 [24]
      (245) |11111111|11111111|11010010| [24]          ffffd2 [24]
      (246) |11111111|11111111|11010011| [24]          ffffd3 [24]
      (247) |11111111|11111111|11010100| [24]          ffffd4 [24]
      (248) |11111111|11111111|11010101| [24]          ffffd5 [24]
      (249) |11111111|11111111|11010110| [24]          ffffd6 [24]
      (250) |11111111|11111111|11010111| [24]          ffffd7 [24]
      (251) |11111111|11111111|11011000| [24]          ffffd8 [24]
      (252) |11111111|11111111|11011001| [24]          ffffd9 [24]
      (253) |11111111|11111111|11011010| [24]          ffffda [24]
      (254) |11111111|11111111|11011011| [24]          ffffdb [24]
      (255) |11111111|11111111|11011100| [24]          ffffdc [24]
  EOS (256) |11111111|11111111|11011101| [24]          ffffdd [24]

Appendix E. Examples

A number of examples are worked through here, for both requests and responses, and with and without huffman coding.

E.1. Request Decoding Example With Huffman

# Header set to be encoded
:method: GET
:scheme: http
:path: /
:authority: www.foo.com

# Hexdump of encoded data which will be decoded
02 84 f7 77 78 ff 07 83 ce 31 77 06 81 0f 04 88 | ...wx....1w.....
db 6d 89 8b 5a 44 b7 4f                         | .m..ZD.O

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '02'
    name_index:
        encoded: "02"
        decoded: 2
    value_data_length:
        encoded: "84"
        decoded: 4
    value_data:
        is_huffman_encoded: 1
        encoded: "f77778ff"
        decoded: "GET"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '07'
    name_index:
        encoded: "07"
        decoded: 7
    value_data_length:
        encoded: "83"
        decoded: 3
    value_data:
        is_huffman_encoded: 1
        encoded: "ce3177"
        decoded: "http"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '06'
    name_index:
        encoded: "06"
        decoded: 6
    value_data_length:
        encoded: "81"
        decoded: 1
    value_data:
        is_huffman_encoded: 1
        encoded: "0f"
        decoded: "/"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "88"
        decoded: 8
    value_data:
        is_huffman_encoded: 1
        encoded: "db6d898b5a44b74f"
        decoded: "www.foo.com"


# Decoded header set
:authority: www.foo.com
:method: GET
:path: /
:scheme: http

#########################

# Header set to be encoded
:method: GET
:scheme: https
:path: /
:authority: www.bar.com
cache-control: no-cache

# Hexdump of encoded data which will be decoded
03 84 ce 31 74 3f 02 88 db 6d 89 7a 1e 44 b7 4f | ...1t?...m.z.D.O
1d 86 63 65 4a 13 98 ff 83 85                   | ..ceJ.....

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "84"
        decoded: 4
    value_data:
        is_huffman_encoded: 1
        encoded: "ce31743f"
        decoded: "https"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '02'
    name_index:
        encoded: "02"
        decoded: 2
    value_data_length:
        encoded: "88"
        decoded: 8
    value_data:
        is_huffman_encoded: 1
        encoded: "db6d897a1e44b74f"
        decoded: "www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '1d'
    name_index:
        encoded: "1d"
        decoded: 29
    value_data_length:
        encoded: "86"
        decoded: 6
    value_data:
        is_huffman_encoded: 1
        encoded: "63654a1398ff"
        decoded: "no-cache"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '83'
    entry_index:
        encoded: "83"
        decoded: 3

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5


# Decoded header set
:authority: www.bar.com
:method: GET
:path: /
:scheme: https
cache-control: no-cache

#########################

# Header set to be encoded
:method: GET
:scheme: https
:path: /custom-path.css
:authority: www.bar.com
custom-key: custom-value

# Hexdump of encoded data which will be decoded
05 8b 04 eb 08 b7 49 5c 88 e6 44 c2 1f 00 88 4e | ......I\..D....N
b0 8b 74 97 90 fa 7f 89 4e b0 8b 74 97 9a 17 a8 | ..t.....N..t....
ff 82 86                                        | ...

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '05'
    name_index:
        encoded: "05"
        decoded: 5
    value_data_length:
        encoded: "8b"
        decoded: 11
    value_data:
        is_huffman_encoded: 1
        encoded: "04eb08b7495c88e644c21f"
        decoded: "/custom-path.css"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '00'
    name_index:
        encoded: "00"
        decoded: 0
    name_data_length:
        encoded: "88"
        decoded: 8
    name_data:
        is_huffman_encoded: 1
        encoded: "4eb08b749790fa7f"
        decoded: "custom-key"
    value_data_length:
        encoded: "89"
        decoded: 9
    value_data:
        is_huffman_encoded: 1
        encoded: "4eb08b74979a17a8ff"
        decoded: "custom-value"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '82'
    entry_index:
        encoded: "82"
        decoded: 2

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6


# Decoded header set
:authority: www.bar.com
:method: GET
:path: /custom-path.css
:scheme: https
custom-key: custom-value

#########################

E.2. Request Decoding Example Without Huffman

# Header set to be encoded
:method: GET
:scheme: http
:path: /
:authority: www.foo.com

# Hexdump of encoded data which will be decoded
02 03 47 45 54 07 04 68 74 74 70 06 01 2f 04 0b | ..GET..http../..
77 77 77 2e 66 6f 6f 2e 63 6f 6d                | www.foo.com

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '02'
    name_index:
        encoded: "02"
        decoded: 2
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "474554"
        decoded: "GET"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '07'
    name_index:
        encoded: "07"
        decoded: 7
    value_data_length:
        encoded: "04"
        decoded: 4
    value_data:
        is_huffman_encoded: 0
        encoded: "68747470"
        decoded: "http"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '06'
    name_index:
        encoded: "06"
        decoded: 6
    value_data_length:
        encoded: "01"
        decoded: 1
    value_data:
        is_huffman_encoded: 0
        encoded: "2f"
        decoded: "/"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "0b"
        decoded: 11
    value_data:
        is_huffman_encoded: 0
        encoded: "7777772e666f6f2e636f6d"
        decoded: "www.foo.com"


# Decoded header set
:authority: www.foo.com
:method: GET
:path: /
:scheme: http

#########################

# Header set to be encoded
:method: GET
:scheme: https
:path: /
:authority: www.bar.com
cache-control: no-cache

# Hexdump of encoded data which will be decoded
03 05 68 74 74 70 73 02 0b 77 77 77 2e 62 61 72 | ..https..www.bar
2e 63 6f 6d 1d 08 6e 6f 2d 63 61 63 68 65 83 85 | .com..no-cache..

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "05"
        decoded: 5
    value_data:
        is_huffman_encoded: 0
        encoded: "6874747073"
        decoded: "https"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '02'
    name_index:
        encoded: "02"
        decoded: 2
    value_data_length:
        encoded: "0b"
        decoded: 11
    value_data:
        is_huffman_encoded: 0
        encoded: "7777772e6261722e636f6d"
        decoded: "www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '1d'
    name_index:
        encoded: "1d"
        decoded: 29
    value_data_length:
        encoded: "08"
        decoded: 8
    value_data:
        is_huffman_encoded: 0
        encoded: "6e6f2d6361636865"
        decoded: "no-cache"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '83'
    entry_index:
        encoded: "83"
        decoded: 3

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5


# Decoded header set
:authority: www.bar.com
:method: GET
:path: /
:scheme: https
cache-control: no-cache

#########################

# Header set to be encoded
:method: GET
:scheme: https
:path: /custom-path.css
:authority: www.bar.com
custom-key: custom-value

# Hexdump of encoded data which will be decoded
05 10 2f 63 75 73 74 6f 6d 2d 70 61 74 68 2e 63 | ../custom-path.c
73 73 00 0a 63 75 73 74 6f 6d 2d 6b 65 79 0c 63 | ss..custom-key.c
75 73 74 6f 6d 2d 76 61 6c 75 65 82 86          | ustom-value..

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '05'
    name_index:
        encoded: "05"
        decoded: 5
    value_data_length:
        encoded: "10"
        decoded: 16
    value_data:
        is_huffman_encoded: 0
        encoded: "2f637573746f6d2d706174682e637373"
        decoded: "/custom-path.css"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '00'
    name_index:
        encoded: "00"
        decoded: 0
    name_data_length:
        encoded: "0a"
        decoded: 10
    name_data:
        is_huffman_encoded: 0
        encoded: "637573746f6d2d6b6579"
        decoded: "custom-key"
    value_data_length:
        encoded: "0c"
        decoded: 12
    value_data:
        is_huffman_encoded: 0
        encoded: "637573746f6d2d76616c7565"
        decoded: "custom-value"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '82'
    entry_index:
        encoded: "82"
        decoded: 2

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6


# Decoded header set
:authority: www.bar.com
:method: GET
:path: /custom-path.css
:scheme: https
custom-key: custom-value

#########################

E.3. Response Decoding Example With Huffman

# Header set to be encoded
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

# Hexdump of encoded data which will be decoded
08 82 40 9f 18 86 c3 1b 39 bf 38 7f 22 92 a2 fb | ..@.....9.8."...
a2 03 20 f2 eb cc 0c 49 00 62 d2 43 4c 82 7a 1d | .. ....I.b.CL.z.
2f 91 68 71 cf 3c 32 6e bd 7e 9e 9e 92 6e 7e 32 | /.hq.<2n.~...n~2
55 7d bf                                        | U}.

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '08'
    name_index:
        encoded: "08"
        decoded: 8
    value_data_length:
        encoded: "82"
        decoded: 2
    value_data:
        is_huffman_encoded: 1
        encoded: "409f"
        decoded: "302"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '18'
    name_index:
        encoded: "18"
        decoded: 24
    value_data_length:
        encoded: "86"
        decoded: 6
    value_data:
        is_huffman_encoded: 1
        encoded: "c31b39bf387f"
        decoded: "private"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '22'
    name_index:
        encoded: "22"
        decoded: 34
    value_data_length:
        encoded: "92"
        decoded: 18
    value_data:
        is_huffman_encoded: 1
        encoded: "a2fba20320f2ebcc0c490062d2434c827a1d"
        decoded: "Mon, 21 OCt 2013 20:13:21 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '2f'
    name_index:
        encoded: "2f"
        decoded: 47
    value_data_length:
        encoded: "91"
        decoded: 17
    value_data:
        is_huffman_encoded: 1
        encoded: "6871cf3c326ebd7e9e9e926e7e32557dbf"
        decoded: ": https://www.bar.com"


# Decoded header set
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
04 82 31 1f 03 92 a2 fb a2 03 20 f2 eb cc 0c 49 | ..1....... ....I
00 62 d2 43 4c c2 7a 1d 03 90 e3 9e 78 64 dd 7a | .b.CL.z.....xd.z
fd 3d 3d 24 dc fc 64 aa fb 7f 20 84 e1 fb b3 0f | .==$..d... .....
3d ff ee 02 df 7d fb 36 ed db b7 6e dd bb 76 ed | =....}.6...n..v.
db b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 | ..n..v...n..v...
6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd | n..v...n..v...n.
bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 | .v...n..v...n..v
ed db b7 6e dd bb 7e 3b 69 ec f0 fe 7e 1f d7 f3 | ...n..~;i...~...
d5 fe 7f 7e 5f d7 9f 6f 97 cb bf e9 b7 fb fe bc | ...~_..o........
fb 7c bb fe 9b 7f bf 8f 87 f3 f0 fe bc fc bb 7b | .|.............{
fe 9b 7e 3f d7 9f 6f 97 7f d3 6f f7 f1 fe bb 7e | ..~?..o...o....~
9b 7f bf 8f c7 f9 f0 db 4f 67 f5 e7 db e5 f4 ef | ........Og......
db fd f8 91 a1 3f 1d b4 f6 78 7f 3f 0f eb f9 ea | .....?...x.?....
ff 3f bf 2f eb cf b7 cb e5 df f4 db fd ff 5e 7d | .?./..........^}
be 5d ff 4d bf df c7 c3 f9 f8 7f 5e 7e 5d bd ff | .].M.......^~]..
4d bf 1f eb cf b7 cb bf e9 b7 fb f8 ff 5d bf 4d | M............].M
bf df c7 e3 fc f8 6d a7 b3 fa f3 ed f2 fa 77 ed | ......m.......w.
fe fc 48 d0 9f 8e da 7b 3c 3f 9f 87 f5 fc f5 7f | ..H....{<?......
9f df 97 f5 e7 db e5 f2 ef fa 6d fe ff af 3e df | ..........m...>.
2e ff a6 df ef e3 e1 fc fc 3f af 3f 2e de ff a6 | .........?.?....
df 8f f5 e7 db e5 df f4 db fd fc 7f ae df a6 df | ................
ef e3 f1 fe 7c 36 d3 d9 fd 79 f6 f9 7d 3b f6 ff | ....|6...y..};..
7e 24 68 4f c7 6d 3d 9e 1f cf c3 fa fe 7a bf cf | ~$hO.m=......z..
ef cb fa f3 ed f2 f9 77 fd 36 ff 7f d7 9f 6f 97 | .......w.6....o.
7f d3 6f f7 f1 f0 fe 7e 1f d7 9f 97 6f 7f d3 6f | ..o....~....o..o
c7 fa f3 ed f2 ef fa 6d fe fe 3f d7 6f d3 6f f7 | .......m..?.o.o.
f1 f8 ff 3e 1b 69 ec fe bc fb 7c be 9d fb 7f bf | ...>.i....|.....
12 34 27 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f | .4'..?....?....?
cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf | ....?....?....?.
f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 | ...?....?....?..
fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc | ..?....?....?...
ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff | .?....?....?....
3f cf f3 fc ff 3f cf f3 fc ff 3f cf f0 8d 09 0b | ?....?....?.....
5f d2 37 f0 86 c4 4a 23 ef 0e 70 c7 2b 2f bb 61 | _.7...J#..p.+/.a
7f 85 86 88                                     | ....

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "82"
        decoded: 2
    value_data:
        is_huffman_encoded: 1
        encoded: "311f"
        decoded: "200"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "92"
        decoded: 18
    value_data:
        is_huffman_encoded: 1
        encoded: "a2fba20320f2ebcc0c490062d2434cc27a1d"
        decoded: "Mon, 21 OCt 2013 20:13:22 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "90"
        decoded: 16
    value_data:
        is_huffman_encoded: 1
        encoded: "e39e7864dd7afd3d3d24dcfc64aafb7f"
        decoded: "https://www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '20'
    name_index:
        encoded: "20"
        decoded: 32
    value_data_length:
        encoded: "84"
        decoded: 4
    value_data:
        is_huffman_encoded: 1
        encoded: "e1fbb30f"
        decoded: "gzip"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '3d'
    name_index:
        encoded: "3d"
        decoded: 61
    value_data_length:
        encoded: "ffee02"
        decoded: 493
    value_data:
        is_huffman_encoded: 1
        encoded: "df7dfb36eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76edd\
bb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddb\
b76eddbb7e3b69ecf0fe7e1fd7f3d5fe7f7e5fd79f6f97cbbfe9b7fbfebcfb7cbbfe9b7\
fbf8f87f3f0febcfcbb7bfe9b7e3fd79f6f977fd36ff7f1febb7e9b7fbf8fc7f9f0db4f\
67f5e7dbe5f4efdbfdf891a13f1db4f6787f3f0febf9eaff3fbf2febcfb7cbe5dff4dbf\
dff5e7dbe5dff4dbfdfc7c3f9f87f5e7e5dbdff4dbf1febcfb7cbbfe9b7fbf8ff5dbf4d\
bfdfc7e3fcf86da7b3faf3edf2fa77edfefc48d09f8eda7b3c3f9f87f5fcf57f9fdf97f\
5e7dbe5f2effa6dfeffaf3edf2effa6dfefe3e1fcfc3faf3f2edeffa6df8ff5e7dbe5df\
f4dbfdfc7faedfa6dfefe3f1fe7c36d3d9fd79f6f97d3bf6ff7e24684fc76d3d9e1fcfc\
3fafe7abfcfefcbfaf3edf2f977fd36ff7fd79f6f977fd36ff7f1f0fe7e1fd79f976f7f\
d36fc7faf3edf2effa6dfefe3fd76fd36ff7f1f8ff3e1b69ecfebcfb7cbe9dfb7fbf123\
427fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcf\
f3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff\
3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff08d090b5fd237f086c44a23ef0e70c7\
2b2fbb617f"
        decoded: "foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '88'
    entry_index:
        encoded: "88"
        decoded: 8


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
01 ff ee 02 df 7d fb 3f cf f3 fc ff 3f cf f3 fc | .....}.?....?...
ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff | .?....?....?....
3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f | ?....?....?....?
cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf | ....?....?....?.
f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 | ...?....?....?..
fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc | ..?....?....?...
ff 3e 3b 69 ec f0 fe 7e 1f d7 f3 d5 fe 7f 7e 5f | .>;i...~......~_
d7 9f 6f 97 cb bf e9 b7 fb fe bc fb 7c bb fe 9b | ..o.........|...
7f bf 8f 87 f3 f0 fe bc fc bb 7b fe 9b 7e 3f d7 | ..........{..~?.
9f 6f 97 7f d3 6f f7 f1 fe bb 7e 9b 7f bf 8f c7 | .o...o....~.....
f9 f0 db 4f 67 f5 e7 db e5 f4 ef db fd f8 91 a1 | ...Og...........
3f 1d b4 f6 78 7f 3f 0f eb f9 ea ff 3f bf 2f eb | ?...x.?.....?./.
cf b7 cb e5 df f4 db fd ff 5e 7d be 5d ff 4d bf | .........^}.].M.
df c7 c3 f9 f8 7f 5e 7e 5d bd ff 4d bf 1f eb cf | ......^~]..M....
b7 cb bf e9 b7 fb f8 ff 5d bf 4d bf df c7 e3 fc | ........].M.....
f8 6d a7 b3 fa f3 ed f2 fa 77 ed fe fc 48 d0 9f | .m.......w...H..
8e da 7b 3c 3f 9f 87 f5 fc f5 7f 9f df 97 f5 e7 | ..{<?...........
db e5 f2 ef fa 6d fe ff af 3e df 2e ff a6 df ef | .....m...>......
e3 e1 fc fc 3f af 3f 2e de ff a6 df 8f f5 e7 db | ....?.?.........
e5 df f4 db fd fc 7f ae df a6 df ef e3 f1 fe 7c | ...............|
36 d3 d9 fd 79 f6 f9 7d 3b f6 ff 7e 24 68 4f c7 | 6...y..};..~$hO.
6d 3d 9e 1f cf c3 fa fe 7a bf cf ef cb fa f3 ed | m=......z.......
f2 f9 77 fd 36 ff 7f d7 9f 6f 97 7f d3 6f f7 f1 | ..w.6....o...o..
f0 fe 7e 1f d7 9f 97 6f 7f d3 6f c7 fa f3 ed f2 | ..~....o..o.....
ef fa 6d fe fe 3f d7 6f d3 6f f7 f1 f8 ff 3e 1b | ..m..?.o.o....>.
69 ec fe bc fb 7c be 9d fb 7f bf 12 34 27 6e dd | i....|......4'n.
bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 | .v...n..v...n..v
ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db | ...n..v...n..v..
b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 6e | .n..v...n..v...n
dd bb 76 ed db b7 6e dd bb 76 ed db b4 8d 09 0b | ..v...n..v......
5f d2 37 f0 86 c4 4a 23 ef 0e 70 c7 2b 2f bb 61 | _.7...J#..p.+/.a
7f 81                                           | ..

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '01'
    name_index:
        encoded: "01"
        decoded: 1
    value_data_length:
        encoded: "ffee02"
        decoded: 493
    value_data:
        is_huffman_encoded: 1
        encoded: "df7dfb3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3f\
cff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fc\
ff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3e3b69ecf\
0fe7e1fd7f3d5fe7f7e5fd79f6f97cbbfe9b7fbfebcfb7cbbfe9b7fbf8f87f3f0febcfc\
bb7bfe9b7e3fd79f6f977fd36ff7f1febb7e9b7fbf8fc7f9f0db4f67f5e7dbe5f4efdbf\
df891a13f1db4f6787f3f0febf9eaff3fbf2febcfb7cbe5dff4dbfdff5e7dbe5dff4dbf\
dfc7c3f9f87f5e7e5dbdff4dbf1febcfb7cbbfe9b7fbf8ff5dbf4dbfdfc7e3fcf86da7b\
3faf3edf2fa77edfefc48d09f8eda7b3c3f9f87f5fcf57f9fdf97f5e7dbe5f2effa6dfe\
ffaf3edf2effa6dfefe3e1fcfc3faf3f2edeffa6df8ff5e7dbe5dff4dbfdfc7faedfa6d\
fefe3f1fe7c36d3d9fd79f6f97d3bf6ff7e24684fc76d3d9e1fcfc3fafe7abfcfefcbfa\
f3edf2f977fd36ff7fd79f6f977fd36ff7f1f0fe7e1fd79f976f7fd36fc7faf3edf2eff\
a6dfefe3fd76fd36ff7f1f8ff3e1b69ecfebcfb7cbe9dfb7fbf1234276eddbb76eddbb7\
6eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76\
eddbb76eddbb76eddbb76eddbb76eddbb76eddbb48d090b5fd237f086c44a23ef0e70c7\
2b2fbb617f"
        decoded: "foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '81'
    entry_index:
        encoded: "81"
        decoded: 1


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

#########################

E.4. Response Decoding Example Without Huffman

# Header set to be encoded
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

# Hexdump of encoded data which will be decoded
08 03 33 30 32 18 07 70 72 69 76 61 74 65 22 1d | ..302..private".
4d 6f 6e 2c 20 32 31 20 4f 43 74 20 32 30 31 33 | Mon, 21 OCt 2013
20 32 30 3a 31 33 3a 32 31 20 47 4d 54 2f 15 3a |  20:13:21 GMT/.:
20 68 74 74 70 73 3a 2f 2f 77 77 77 2e 62 61 72 |  https://www.bar
2e 63 6f 6d                                     | .com

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '08'
    name_index:
        encoded: "08"
        decoded: 8
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "333032"
        decoded: "302"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '18'
    name_index:
        encoded: "18"
        decoded: 24
    value_data_length:
        encoded: "07"
        decoded: 7
    value_data:
        is_huffman_encoded: 0
        encoded: "70726976617465"
        decoded: "private"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '22'
    name_index:
        encoded: "22"
        decoded: 34
    value_data_length:
        encoded: "1d"
        decoded: 29
    value_data:
        is_huffman_encoded: 0
        encoded: "4d6f6e2c203231204f437420323031332032303a31333a3231204\
74d54"
        decoded: "Mon, 21 OCt 2013 20:13:21 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '2f'
    name_index:
        encoded: "2f"
        decoded: 47
    value_data_length:
        encoded: "15"
        decoded: 21
    value_data:
        is_huffman_encoded: 0
        encoded: "3a2068747470733a2f2f7777772e6261722e636f6d"
        decoded: ": https://www.bar.com"


# Decoded header set
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
04 03 32 30 30 03 1d 4d 6f 6e 2c 20 32 31 20 4f | ..200..Mon, 21 O
43 74 20 32 30 31 33 20 32 30 3a 31 33 3a 32 32 | Ct 2013 20:13:22
20 47 4d 54 03 13 68 74 74 70 73 3a 2f 2f 77 77 |  GMT..https://ww
77 2e 62 61 72 2e 63 6f 6d 20 04 67 7a 69 70 3d | w.bar.com .gzip=
7f e1 02 66 6f 6f 3d 41 41 41 41 41 41 41 41 41 | ...foo=AAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 4c | AAAAAAAAAAAAAAAL
41 53 44 4a 4b 48 51 4b 42 5a 58 4f 51 57 45 4f | ASDJKHQKBZXOQWEO
50 49 55 41 58 51 57 45 4f 49 55 41 58 4c 4a 4b | PIUAXQWEOIUAXLJK
48 51 57 4f 45 49 55 41 4c 51 57 45 4f 49 55 41 | HQWOEIUALQWEOIUA
58 4c 51 45 55 41 58 4c 4c 4b 4a 41 53 44 51 57 | XLQEUAXLLKJASDQW
45 4f 55 49 41 58 4e 31 32 33 34 4c 41 53 44 4a | EOUIAXN1234LASDJ
4b 48 51 4b 42 5a 58 4f 51 57 45 4f 50 49 55 41 | KHQKBZXOQWEOPIUA
58 51 57 45 4f 49 55 41 58 4c 4a 4b 48 51 57 4f | XQWEOIUAXLJKHQWO
45 49 55 41 4c 51 57 45 4f 49 55 41 58 4c 51 45 | EIUALQWEOIUAXLQE
55 41 58 4c 4c 4b 4a 41 53 44 51 57 45 4f 55 49 | UAXLLKJASDQWEOUI
41 58 4e 31 32 33 34 4c 41 53 44 4a 4b 48 51 4b | AXN1234LASDJKHQK
42 5a 58 4f 51 57 45 4f 50 49 55 41 58 51 57 45 | BZXOQWEOPIUAXQWE
4f 49 55 41 58 4c 4a 4b 48 51 57 4f 45 49 55 41 | OIUAXLJKHQWOEIUA
4c 51 57 45 4f 49 55 41 58 4c 51 45 55 41 58 4c | LQWEOIUAXLQEUAXL
4c 4b 4a 41 53 44 51 57 45 4f 55 49 41 58 4e 31 | LKJASDQWEOUIAXN1
32 33 34 4c 41 53 44 4a 4b 48 51 4b 42 5a 58 4f | 234LASDJKHQKBZXO
51 57 45 4f 50 49 55 41 58 51 57 45 4f 49 55 41 | QWEOPIUAXQWEOIUA
58 4c 4a 4b 48 51 57 4f 45 49 55 41 4c 51 57 45 | XLJKHQWOEIUALQWE
4f 49 55 41 58 4c 51 45 55 41 58 4c 4c 4b 4a 41 | OIUAXLQEUAXLLKJA
53 44 51 57 45 4f 55 49 41 58 4e 31 32 33 34 5a | SDQWEOUIAXN1234Z
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 31 32 33 34 20 6d 61 78 2d | ZZZZZZZ1234 max-
61 67 65 3d 33 36 30 30 3b 20 76 65 72 73 69 6f | age=3600; versio
6e 3d 31 85 86 88                               | n=1...

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "323030"
        decoded: "200"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "1d"
        decoded: 29
    value_data:
        is_huffman_encoded: 0
        encoded: "4d6f6e2c203231204f437420323031332032303a31333a3232204\
74d54"
        decoded: "Mon, 21 OCt 2013 20:13:22 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "13"
        decoded: 19
    value_data:
        is_huffman_encoded: 0
        encoded: "68747470733a2f2f7777772e6261722e636f6d"
        decoded: "https://www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '20'
    name_index:
        encoded: "20"
        decoded: 32
    value_data_length:
        encoded: "04"
        decoded: 4
    value_data:
        is_huffman_encoded: 0
        encoded: "677a6970"
        decoded: "gzip"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '3d'
    name_index:
        encoded: "3d"
        decoded: 61
    value_data_length:
        encoded: "7fe102"
        decoded: 480
    value_data:
        is_huffman_encoded: 0
        encoded: "666f6f3d414141414141414141414141414141414141414141414\
14141414141414141414141414141414141414141414141414141414141414141414141\
41414141414141414141414141414c4153444a4b48514b425a584f5157454f504955415\
85157454f495541584c4a4b4851574f454955414c5157454f495541584c51455541584c\
4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a584f5157454\
f50495541585157454f495541584c4a4b4851574f454955414c5157454f495541584c51\
455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a5\
84f5157454f50495541585157454f495541584c4a4b4851574f454955414c5157454f49\
5541584c51455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b4\
8514b425a584f5157454f50495541585157454f495541584c4a4b4851574f454955414c\
5157454f495541584c51455541584c4c4b4a4153445157454f554941584e313233345a5\
a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a\
5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a3\
1323334206d61782d6167653d333630303b2076657273696f6e3d31"
        decoded: "foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '88'
    entry_index:
        encoded: "88"
        decoded: 8


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
01 7f e1 02 66 6f 6f 3d 5a 5a 5a 5a 5a 5a 5a 5a | ....foo=ZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
4c 41 53 44 4a 4b 48 51 4b 42 5a 58 4f 51 57 45 | LASDJKHQKBZXOQWE
4f 50 49 55 41 58 51 57 45 4f 49 55 41 58 4c 4a | OPIUAXQWEOIUAXLJ
4b 48 51 57 4f 45 49 55 41 4c 51 57 45 4f 49 55 | KHQWOEIUALQWEOIU
41 58 4c 51 45 55 41 58 4c 4c 4b 4a 41 53 44 51 | AXLQEUAXLLKJASDQ
57 45 4f 55 49 41 58 4e 31 32 33 34 4c 41 53 44 | WEOUIAXN1234LASD
4a 4b 48 51 4b 42 5a 58 4f 51 57 45 4f 50 49 55 | JKHQKBZXOQWEOPIU
41 58 51 57 45 4f 49 55 41 58 4c 4a 4b 48 51 57 | AXQWEOIUAXLJKHQW
4f 45 49 55 41 4c 51 57 45 4f 49 55 41 58 4c 51 | OEIUALQWEOIUAXLQ
45 55 41 58 4c 4c 4b 4a 41 53 44 51 57 45 4f 55 | EUAXLLKJASDQWEOU
49 41 58 4e 31 32 33 34 4c 41 53 44 4a 4b 48 51 | IAXN1234LASDJKHQ
4b 42 5a 58 4f 51 57 45 4f 50 49 55 41 58 51 57 | KBZXOQWEOPIUAXQW
45 4f 49 55 41 58 4c 4a 4b 48 51 57 4f 45 49 55 | EOIUAXLJKHQWOEIU
41 4c 51 57 45 4f 49 55 41 58 4c 51 45 55 41 58 | ALQWEOIUAXLQEUAX
4c 4c 4b 4a 41 53 44 51 57 45 4f 55 49 41 58 4e | LLKJASDQWEOUIAXN
31 32 33 34 4c 41 53 44 4a 4b 48 51 4b 42 5a 58 | 1234LASDJKHQKBZX
4f 51 57 45 4f 50 49 55 41 58 51 57 45 4f 49 55 | OQWEOPIUAXQWEOIU
41 58 4c 4a 4b 48 51 57 4f 45 49 55 41 4c 51 57 | AXLJKHQWOEIUALQW
45 4f 49 55 41 58 4c 51 45 55 41 58 4c 4c 4b 4a | EOIUAXLQEUAXLLKJ
41 53 44 51 57 45 4f 55 49 41 58 4e 31 32 33 34 | ASDQWEOUIAXN1234
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 31 32 33 34 20 6d 61 78 | AAAAAAAA1234 max
2d 61 67 65 3d 33 36 30 30 3b 20 76 65 72 73 69 | -age=3600; versi
6f 6e 3d 31 81                                  | on=1.

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '01'
    name_index:
        encoded: "01"
        decoded: 1
    value_data_length:
        encoded: "7fe102"
        decoded: 480
    value_data:
        is_huffman_encoded: 0
        encoded: "666f6f3d5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5\
a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a\
5a5a5a5a5a5a5a5a5a5a5a5a5a5a4c4153444a4b48514b425a584f5157454f504955415\
85157454f495541584c4a4b4851574f454955414c5157454f495541584c51455541584c\
4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a584f5157454\
f50495541585157454f495541584c4a4b4851574f454955414c5157454f495541584c51\
455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a5\
84f5157454f50495541585157454f495541584c4a4b4851574f454955414c5157454f49\
5541584c51455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b4\
8514b425a584f5157454f50495541585157454f495541584c4a4b4851574f454955414c\
5157454f495541584c51455541584c4c4b4a4153445157454f554941584e31323334414\
14141414141414141414141414141414141414141414141414141414141414141414141\
41414141414141414141414141414141414141414141414141414141414141414141413\
1323334206d61782d6167653d333630303b2076657273696f6e3d31"
        decoded: "foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '81'
    entry_index:
        encoded: "81"
        decoded: 1


# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

#########################

Authors' Addresses

Roberto Peon Google, Inc EMail: fenix@google.com

Hervé Ruellan Canon CRF EMail: herve.ruellan@crf.canon.fr

[HTTP2]	Belshe, M., Peon, R., Thomson, M. and A. Melnikov, "Hypertext Transfer Protocol version 2.0", Internet-Draft draft-ietf-httpbis-http2-06, August 2013.
[HTTP-p1]	Fielding, R. and J. F. Reschke, "Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing", Internet-Draft draft-ietf-httpbis-p1-messaging-24, September 2013.

[SPDY]	Belshe, M. and R. Peon, "SPDY Protocol", Internet-Draft draft-mbelshe-httpbis-spdy-00, February 2012.
[CRIME]	Rizzo, J. and T. Duong, "The Crime Attack", September 2012.
[PERF1]	Belshe, M., "IETF83: SPDY and What to Consider for HTTP/2.0", March 2012.
[PERF2]	McManus, P., "SPDY: What I Like About You", September 2011.
[HUFF]	Huffman, D. A., "A Method for the Construction of Minimim Redundancy Codes", Proceedings of the Institute of Radio Engineers Volume 40, Number 9, pp. 1098-1101, September 1952.
[CANON]	Schwartz, E. S. and B. Kallick, "Generating a canonical prefix encoding", Communications of the ACM Volume 7 Issue 3, pp. 166-169, March 1964.