Internet DRAFT - draft-hallambaker-dare-message
draft-hallambaker-dare-message
Network Working Group P. Hallam-Baker
Internet-Draft Comodo Group Inc.
Intended status: Informational August 27, 2018
Expires: February 28, 2019
Data At Rest Encryption Part 1: DARE Message Syntax
draft-hallambaker-dare-message-02
Abstract
This document describes the Data At Rest Encryption (DARE) message
syntax. This syntax is used to digitally sign, digest, authenticate,
or encrypt arbitrary message content.
This document is also available online at
http://mathmesh.com/Documents/draft-hallambaker-dare-message.html [1]
.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 28, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
Hallam-Baker Expires February 28, 2019 [Page 1]
Internet-Draft DARE Message August 2018
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Encryption and Integrity . . . . . . . . . . . . . . . . 3
1.1.1. Key Exchange . . . . . . . . . . . . . . . . . . . . 4
1.1.2. Data Erasure . . . . . . . . . . . . . . . . . . . . 5
1.2. Signature . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.1. Signing Individual Plaintext Messages . . . . . . . . 6
1.2.2. Signing Individual Encrypted Messages . . . . . . . . 6
1.2.3. Signing Sequences of Messages . . . . . . . . . . . . 6
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Related Specifications . . . . . . . . . . . . . . . . . 7
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 7
2.3. Defined terms . . . . . . . . . . . . . . . . . . . . . . 7
3. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Processing Considerations . . . . . . . . . . . . . . . . 9
3.2. Content Metadata and Annotations . . . . . . . . . . . . 10
3.3. Encoded Data Sequence . . . . . . . . . . . . . . . . . . 11
3.4. Encryption and Integrity . . . . . . . . . . . . . . . . 12
3.4.1. Key Exchange . . . . . . . . . . . . . . . . . . . . 13
3.4.2. Key Identifiers . . . . . . . . . . . . . . . . . . . 14
3.4.3. Salt Derivation . . . . . . . . . . . . . . . . . . . 14
3.4.4. Key Derivation . . . . . . . . . . . . . . . . . . . 15
3.5. Signature . . . . . . . . . . . . . . . . . . . . . . . . 16
4. Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1. Field: kwd . . . . . . . . . . . . . . . . . . . . . . . 16
5. Reference . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1. Message Classes . . . . . . . . . . . . . . . . . . . . . 17
5.1.1. Structure: DAREMessageSequence . . . . . . . . . . . 17
5.2. Header and Trailer Classes . . . . . . . . . . . . . . . 17
5.2.1. Structure: DARETrailer . . . . . . . . . . . . . . . 17
5.2.2. Structure: DAREHeader . . . . . . . . . . . . . . . . 18
5.3. Cryptographic Data . . . . . . . . . . . . . . . . . . . 18
5.3.1. Structure: DARESigner . . . . . . . . . . . . . . . . 19
5.3.2. Structure: X509Certificate . . . . . . . . . . . . . 19
5.3.3. Structure: DARESignature . . . . . . . . . . . . . . 19
5.3.4. Structure: DARERecipient . . . . . . . . . . . . . . 19
6. Security Considerations . . . . . . . . . . . . . . . . . . . 20
6.1. Encryption/Signature nesting . . . . . . . . . . . . . . 20
6.2. Side channel . . . . . . . . . . . . . . . . . . . . . . 20
6.3. Salt reuse . . . . . . . . . . . . . . . . . . . . . . . 20
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20
9. Test Examples . . . . . . . . . . . . . . . . . . . . . . . . 20
9.1. Plaintext Message . . . . . . . . . . . . . . . . . . . . 22
Hallam-Baker Expires February 28, 2019 [Page 2]
Internet-Draft DARE Message August 2018
9.2. Plaintext Message with EDS . . . . . . . . . . . . . . . 22
9.3. Encrypted Message . . . . . . . . . . . . . . . . . . . . 22
9.4. Signed Message . . . . . . . . . . . . . . . . . . . . . 25
9.5. Signed and Encrypted Message . . . . . . . . . . . . . . 26
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
10.1. Normative References . . . . . . . . . . . . . . . . . . 27
10.2. Informative References . . . . . . . . . . . . . . . . . 28
10.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction
This document describes the Data At Rest Encryption (DARE) Message
Syntax. This syntax is used to digitally sign, digest, authenticate,
or encrypt arbitrary message content.
The DARE Message Syntax is based on a subset of the JSON Web
Signature [RFC7515] and JSON Web Encryption [RFC7516] standards and
shares many fields and semantics. The processing model and data
structures have been streamlined to remove alternative means of
specifying the same content.
A DARE Message consists of a Header, Payload and an optional Trailer.
To enable single pass encoding and decoding, the Header contains all
the information required to perform cryptographic processing of the
Payload and authentication data (digest, MAC, signature values) may
be deferred to the Trailer section.
The DARE Message Syntax is designed to compliment the DARE Container
syntax. A DARE Container is an append-only log format consisting of
a sequence of frames. Cryptographic enhancements (signature,
encryption) may be applied to individual frames or to sets of frames.
Thus, a single key exchange may be used to provide a master key to
encrypt multiple frames and a single signature may be used to
authenticate all the frames in the container up to and including the
frame in which the signature is presented.
The DARE Message syntax may be used either as a standalone
cryptographic message syntax or as a means of presenting a single
DARE Container frame together with the complete cryptographic context
required to verify the contents and decrypt them.
1.1. Encryption and Integrity
An important innovation in the DARE Message Syntax is the separation
of key exchange and data encryption operations so that a Master Key
(MK) established in a single exchange to be applied to multiple octet
sequences. This means that a public key operation may be used to
Hallam-Baker Expires February 28, 2019 [Page 3]
Internet-Draft DARE Message August 2018
encrypt multiple parts of the same message or to multiple frames in a
DARE Container.
To avoid reuse of the key and to avoid the need to communicate
separate IVs, each octet sequence is encrypted under a different
encryption key (and IV if required) derived from the Master Key by
means of a salt that is unique for each octet sequence that is
encrypted. The same approach is used to generate keys for
calculating a MAC over the octet sequence if required. This approach
allows encryption and integrity protections to be applied to the
message payload, to header or trailer fields or to application
defined Enhanced Data Sequences in the header or trailer.
1.1.1. Key Exchange
Traditional cryptographic containers describe the application of a
single key exchange to encryption of a single octet sequence.
Examples include PCKS#7/CMS [RFC2315] , OpenPGP [RFC4880] and JSON
Web Encryption [RFC7516] .
To encrypt a message using RSA, the encoder first generates a random
encryption key and initialization vector (IV). The encryption key is
encrypted under the public key of each recipient to create a per-
recipient decryption entry. The encryption key, plaintext and IV are
used to generate the ciphertext (figure 1).
[[This figure is not viewable in this format. The figure is
available at http://mathmesh.com/Documents/draft-hallambaker-dare-
message.html [2].]]
Monolithic Key Exchange and Encrypt
This approach is adequate for the task of encrypting a single octet
stream. It is less than satisfactory when encrypting multiple octet
streams or very long streams for which a rekeying operation is
desirable.
In the DARE approach, key exchange and key derivation are separate
operations and keys MAY be derived for encryption or integrity
purposes or both. A single key exchange MAY be used to derive keys
to apply encryption and integrity enhancements to multiple data
sequences.
The DARE key exchange begins with the same key exchange used to
produce the CEK in JWE but instead of using the CEK to encipher data
directly, it is used as one of the inputs to a Key Derivation
Function (KDF) that is used to derive parameters for each block of
Hallam-Baker Expires February 28, 2019 [Page 4]
Internet-Draft DARE Message August 2018
data to be encrypted. To avoid the need to introduce additional
terminology, the term 'CEK' is still used to describe the output of
the key agreement algorithm (including key unwrapping if required)
but it is more appropriately described as a Master Key (figure 2).
[[This figure is not viewable in this format. The figure is
available at http://mathmesh.com/Documents/draft-hallambaker-dare-
message.html [3].]]
Exchange of Master Key
A Master Key may be used to encrypt any number of data items. Each
data item is encrypted under a different encryption key and IV (if
required). This data is derived from the Master Key using the HKDF
function [RFC5869] using a different salt for each data item and
separate info tags for each cryptographic function (figure 3).
[[This figure is not viewable in this format. The figure is
available at http://mathmesh.com/Documents/draft-hallambaker-dare-
message.html [4].]]
Data item encryption under Master Key and per-item salt.
This approach to encryption offers considerably greater flexibility
allowing the same format for data item encryption to be applied at
the transport, message or field level.
1.1.2. Data Erasure
Each encrypted DARE Message specifies a unique Master Salt value of
at least 128 bits which is used to derive the salt values used to
derive cryptographic keys for the message payload and annotations.
Erasure of the Master Salt value MAY be used to effectively render
the message payload and annotations undecipherable without altering
the message payload data. The work factor for decryption will be
O(2^128) even if the decryption key is compromised.
1.2. Signature
As with encryption, DARE Message signatures MAY be applied to an
individual message or a sequence of messages.
Hallam-Baker Expires February 28, 2019 [Page 5]
Internet-Draft DARE Message August 2018
1.2.1. Signing Individual Plaintext Messages
When an individual plaintext message is signed, the digest value used
to create the signature is calculated over the binary value of the
payload data. That is, the value of the payload before the encoding
(Base-64, JSON-B) is applied.
1.2.2. Signing Individual Encrypted Messages
When an individual plaintext message is signed, the digest value used
to create the signature is calculated over the binary value of the
payload data. That is, the value of the payload after encryption but
before the encoding (Base-64, JSON-B) is applied.
Use of signing and encryption in combination presents the risk of
subtle attacks depending on the order in which signing and encryption
take place [Davis2001] .
Na?ve approaches in which a message is encrypted and then signed
present the possibility of a surreptitious forwarding attack. For
example, Alice signs a message and sends it to Mallet who then strips
off Alice's signature and sends the message to Bob.
Na?ve approaches in which a message is signed and then encrypted
present the possibility of an attacker claiming authorship of a
ciphertext. For example, Alice encrypts a ciphertext for Bob and
then signs it. Mallet then intercepts the message and sends it to
Bob.
While neither attack is a concern in all applications, both attacks
pose potential hazards for the unwary and require close inspection of
application protocol design to avoid exploitation.
To prevent these attacks, each signature on a message that is signed
and encrypted MUST include a witness value that is calculated by
applying a MAC function to the signature value as described in
section XXX.
1.2.3. Signing Sequences of Messages
To sign multiple messages with a single signature, we first construct
a Merkle tree of the message payload digest values and then sign the
root of the Merkle tree.
[This is not yet implemented but will be soon.]
Hallam-Baker Expires February 28, 2019 [Page 6]
Internet-Draft DARE Message August 2018
2. Definitions
2.1. Related Specifications
The DARE message format is based on the following existing standards
and specifications.
Object serialization The JSON-B [draft-hallambaker-jsonbcd] encoding
is used for object serialization. This encoding is an extension
of the JavaScript Object Notation (JSON) [RFC7159] .
Message syntax The cryptographic processing model is based on JSON
Web Signature (JWS) [RFC7515] , JSON Web Encryption (JWE)
[RFC7516] and JSON Web Key (JWK) [RFC7517] .
Cryptographic primitives. The HMAC-based Extract-and-Expand Key
Derivation Function [RFC5869] and Advanced Encryption Standard
(AES) Key Wrap with Padding Algorithm [RFC3394] are used.
The Uniform Data Fingerprint method of presenting data digests is
used for key identifiers and other purposes
[draft-hallambaker-udf] .
Cryptographic algorithms The cryptographic algorithms and
identifiers described in JSON Web Algorithms (JWA) [RFC7518] are
used together with additional algorithms as defined in the JSON
Object Signing and Encryption IANA registry [IANAJOSE] .
2.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] .
2.3. Defined terms
The terms "Authentication Tag", "Content Encryption Key", "Key
Management Mode", "Key Encryption", "Direct Key Agreement", "Key
Agreement with Key Wrapping" and "Direct Encryption" are defined in
the JWE specification [RFC7516] .
The terms "Authentication", "Ciphertext", "Digital Signature",
"Encryption", "Initialization Vector (IV)", "Message Authentication
Code (MAC)", "Plaintext" and "Salt" are defined by the Internet
Security Glossary, Version 2 [RFC4949] .
Annotated Message A DARE Message that contains an Annotations field
with at least one entry.
Hallam-Baker Expires February 28, 2019 [Page 7]
Internet-Draft DARE Message August 2018
Authentication Data A Message Authentication Code or authentication
tag.
Complete Message A DARE message that contains the key exchange
information necessary for the intended recipient(s) to decrypt it.
Detached Message A DARE message that does not contain the key
exchange information necessary for the intended recipient(s) to
decrypt it.
Encryption Context The master key, encryption algorithms and
associated parameters used to generate a set of one or more
enhanced data sequences.
Encoded data sequence (EDS) A sequence consisting of a salt, content
data and authentication data (if required by the encryption
context).
Enhancement Applying a cryptographic operation to a data sequence.
This includes encryption, authentication and both at the same
time.
Generator The party that generates a DARE message.
Group Encryption Key A key used to encrypt data to be read by a
group of users. This is typically achieved by means of some form
of proxy re-encryption or distributed key generation.
Group Encryption Key Identifier A key identifier for a group
encryption key.
Master Key (MK) The master secret from which keys are derived for
authenticating enhanced data sequences.
Recipient Any party that receives and processes at least some part
of a DARE message.
Related Message A set of DARE messages that share the same key
exchange information and hence the same Master Key.
Uniform Data Fingerprint (UDF) The means of presenting the result of
a cryptographic digest function over a data sequence and content
type identifier specified in the Uniform Data Fingerprint
specification [draft-hallambaker-udf]
Hallam-Baker Expires February 28, 2019 [Page 8]
Internet-Draft DARE Message August 2018
3. Architecture
A DARE message is a sequence of three parts as follows.
Header A JSON object containing information a reader requires to
begin processing the message.
Payload An array of octets.
Trailer A JSON object containing information calculated from the
message payload.
For example, the following sequence is a JSON encoded DARE Message
with an empty header, a payload of zero length and an empty trailer:
[ {}, "", {} ]
Figure 1
DARE Messages MAY be encoded using JSON serialization or a binary
serialization for greater efficiency.
JSON Offers compatibility with applications and libraries that
support JSON. Payload data is encoded using Base64 incurring a
33% overhead.
JSON-B A superset of JSON encoding that permits binary data to be
encoded as a sequence of length-data segments. This avoids the
Base64 overhead incurred by JSON encoding.
JSON-C A superset of JSON-C which provides additional efficiency by
allowing field tags and other repeated string data to be encoded
by reference to a dictionary.
DARE Message processors MUST support JSON serialization and SHOULD
support JSON-B serialization.
3.1. Processing Considerations
The DARE Message Syntax supports single pass encoding and decoding
without buffering of data. All the information required to begin
processing a DARE message (key agreement information, digest
algorithms), is provided in the message header. All the information
that is derived from message processing (authentication codes, digest
values, signatures) is presented in the message trailer.
The choice of message encoding does not affect the semantics of
message processing. A DARE Message MAY be reserialized under the
Hallam-Baker Expires February 28, 2019 [Page 9]
Internet-Draft DARE Message August 2018
same serialization or converted from any of the specified
serialization to any other serialization without changing the
semantics or integrity properties of the message.
3.2. Content Metadata and Annotations
A header MAY contain header fields describing the payload content.
These include:
ContentType Specifies the IANA Content Type.
Annotations A list of Encoded Data Sequences that provide
application specific annotations to the message.
The format of the Encoded Data Sequences is described in the
following section.
Consider the following mail message:
From: Alice@example.com
To: bob@example.com
Subject: TOP-SECRET Product Launch Today!
The CEO told me the product launch is today. Tell no-one!
Figure 2
Existing encryption approaches require that header fields such as the
subject line be encrypted with the body of the message or not
encrypted at all. Neither approach is satisfactory. In this
example, the subject line gives away important information that the
sender probably assumed would be encrypted. But if the subject line
is encrypted together with the message body, a mail client must
retrieve at least part of the message body to provide a 'folder'
view.
The following is a plaintext DARE Message in which the header fields
of the mail message are presented as annotations:
Hallam-Baker Expires February 28, 2019 [Page 10]
Internet-Draft DARE Message August 2018
[{
"cty":"application/example-mail",
"Annotations":["iAEBiBdGcm9tOiBBbGljZUBleGFtcGxlLmNvbYgA",
"iAECiBNUbzogYm9iQGV4YW1wbGUuY29tiAA",
"iAEDiClTdWJqZWN0OiBUT1AtU0VDUkVUIFByb2R1Y3QgTGF1bmNoIFRvZGF5
IYgA"
]},
"VGhlIENFTyB0b2xkIG1lIHRoZSBwcm9kdWN0IGxhdW5jaCBpcyB0b2RheS4gVGVs
bCBuby1vbmUh"
]
Figure 3
3.3. Encoded Data Sequence
An encoded data sequence (EDS) is a sequence of octets that encodes a
data sequence according to cryptographic enhancements specified in
the context in which it is presented. An EDS MAY be encrypted and
MAY be authenticated by means of a MAC. The keys and other
cryptographic parameters used to apply these enhancements are derived
from the cryptographic context and a Salt prefix specified in the EDS
itself.
An EDS sequence contains exactly three binary fields encoded in
JSON-B serialization as follows:
Salt Prefix A sequence of octets used to derive the encryption key,
Initialization Vector and MAC key as required.
Body The plaintext or encrypted content.
Authentication Tag The authentication code value in the case that
the cryptographic context specifies use of authenticated
encryption or a MAC, otherwise is a zero-length field.
Requiring all three fields to be present, even in cases where they
are unnecessary simplifies processing at the cost of up to six
additional data bytes.
The encoding of the 'From' header of the previous example as a
plaintext EDS is as follows:
Hallam-Baker Expires February 28, 2019 [Page 11]
Internet-Draft DARE Message August 2018
88 01
01
88 17
46 72 6f 6d 3a 20 41 6c 69 63 65 40 65 78 61 6d
70 6c 65 2e 63 6f 6d
88 00
~~~~
Figure 4
3.4. Encryption and Integrity
Encryption and integrity protections MAY be applied to any DARE
Message Payload and Annotations.
The following is an encrypted version of the message shown earlier.
The payload and annotations have both increased in size as a result
of the block cipher padding. The header now includes Recipients and
Salt fields to enable the content to be decoded.
Hallam-Baker Expires February 28, 2019 [Page 12]
Internet-Draft DARE Message August 2018
[{
"enc":"A256CBC",
"Salt":"cvbklMnkhoWE1-3_t3Z-UQ",
"cty":"application/example-mail",
"Annotations":["iAEBiCDUKHYfjqs5SHQAzwezya-guHTj0SkhmeHtjbHSWjLa
Fg",
"iAECiCCI5gIDQIVQLnQmnc3ZUHb4rtnq3U-ctF52eEXRdNapxw",
"iAEDiDAsnYWB_5SpxqyX_GLKSW4ztdPbEfsxMAUQnRzr7moJoORh1SxzLLYt
NPovkFVqXBg"
],
"recipients":[{
"kid":"MDAD3-E4BYE-MK6CH-QA2HD-TKRS2-KIX5Y-A",
"epk":{
"PublicKeyDH":{
"kid":"MDIGT-2AA2Q-HFVRN-WYCNY-F32NC-FB4NP-A",
"Domain":"YE6bnq1MlX5ojaJto6PLP_PEwA",
"Public":"a3VlD_zF5tPfV3GxjfsdkdjDjqT0isXW9iwbZeXWGiCBV
dwTIgXAzDF0SqBMLbqe31p1ZEMFh0mas6evqNUCM-yb9HuVtjzaaDcn3_jH2kkgQw
S9_4cD8_qFCazvxwAgKCnLn_VzKOBduT0uvQz1FEuCSv4t0kLlbCwDIe_7TMaoQPN
RcsVvMPPW6lfWkC5CiHaGN78bNCzkmplAbHV2g10oC4_NdRZ6m8kBkXWz3bnnLFGI
KWzXKTgfQXrksSktKa9pkwA_6KWEMiLPPHQhtj7wud09o7TzWfdcz3lFaGeMmTBSH
dFyRl0LSbia9qsrgN6tLUCwOtbuKV3XoEYlvwA"}},
"wmk":"mzXRWy5OjlsZFHT_teqx3E6wtL6eLVFekiUXO_txMUSt3ILj9xgJ
Lw"}
]},
"vTg5MAhAmIKF7LCFeE8xFhqOFQ5znVtkIctqyyctDkTNL69Tf0KhsC5VoVty3JCq
RNth3hIfdHJZlU_BnMRzyA"
]
Figure 5
3.4.1. Key Exchange
The DARE key exchange is based on the JWE key exchange except that
encryption modes are intentionally limited and the output of the key
exchange is the DARE Master Key rather than the Content Encryption
Key.
A DARE Key Exchange MAY contain any number of Recipient entries, each
providing a means of decrypting the Master Key using a different
private key.
If the Key Exchange mechanism supports message recovery, Direct Key
Agreement is used, in all other cases, Key Wrapping is used.
This approach allows messages with one intended recipient to be
handled in the exact same fashion as messages with multiple
recipients. While this does require an additional key wrapping
Hallam-Baker Expires February 28, 2019 [Page 13]
Internet-Draft DARE Message August 2018
operation, that could be avoided if a message has exactly one
intended recipient, this is offset by the reduction in code
complexity.
If the key exchange algorithm does not support message recovery (e.g.
Diffie Hellman and Elliptic Curve Diffie-Hellman), the HKDF Extract-
and-Expand Key Derivation Function is used to derive a master key
using the following info tag:
"dare-master" [64 61 72 65 2d 6d 61 73 74 65 72] Key derivation info
field used when deriving a master key from the output of a key
exchange.
The master key length is the maximum of the key size of the
encryption algorithm specified by the key exchange header, the key
size of the MAC algorithm specified by the key exchange header (if
used) and 256.
3.4.2. Key Identifiers
The JWE/JWS specifications define a kid field for use as a key
identifier but not how the identifier itself is constructed. All
DARE key identifiers are either UDF key fingerprints
[draft-hallambaker-udf] or Mesh/Recrypt Group Key Identifiers.
A UDF fingerprint is formed as the digest of an IANA content type and
the digested data. A UDF key fingerprint is formed with the content
type application/pkix-keyinfo and the digested data is the ASN.1 DER
encoded PKIX certificate keyInfo sequence for the corresponding
public key.
A Group Key Identifier has the form <fingerprint>@<domain>. Where
<fingerprint> is a UDF key fingerprint and <domain> is the DNS
address of a service that provides the encryption service to support
decryption by group members.
3.4.3. Salt Derivation
A Master Salt is a sequence of 16 or more octets that is specified in
the Salt field of the header.
The Master Salt is used to derive salt values for the message payload
and associated encoded data sequences as follows.
Payload
EDS
Hallam-Baker Expires February 28, 2019 [Page 14]
Internet-Draft DARE Message August 2018
Encoders SHOULD NOT generate salt values that exceed 1024 octets.
The salt value is opaque to the DARE encoding but MAY be used to
encode application specific semantics including:
o Frame number to allow reassembly of a data sequence split over a
sequence of messages which may be delivered out of order.
o Transmit the Master Key in the manner of a Kerberos ticket to
allow some (but not necessarily all) to avoid the need to perform
a key exchange.
o Identify the Master Key under which the Enhanced Data Sequence was
generated.
o Enable erasure of the encrypted data plaintext by erasure of the
encryption key.
For data erasure to be effective, the salt MUST be constructed so
that the difficulty of recovering the key is sufficiently high that
it is infeasible. For most purposes, a salt with 128 bits of
appropriately random data is sufficient.
3.4.4. Key Derivation
Encryption and/or authentication keys are derived from the Master Key
using a Extract-and-Expand Key Derivation Function as follows:
1. The Master Key and salt value are used to extract the PRK
(pseudorandom key)
2. The PRK is used to derive the algorithm keys using the
application specific information input for that key type.
The application specific information inputs are:
"dare-encrypt" [64 61 72 65 2d 65 6e 63 72 79 70 74] To generate an
encryption or encryption with authentication key.
"dare-iv" [64 61 72 65 2d 65 6e 63 72 79 70 74] To generate an
initialization vector.
"dare-mac" [dare-mac] To generate a Message Authentication Code key.
Hallam-Baker Expires February 28, 2019 [Page 15]
Internet-Draft DARE Message August 2018
3.5. Signature
While encryption and integrity enhancements can be applied to any
part of a DARE message, signatures are only applied to payload digest
values calculated over one or more message payloads.
The payload digest value for a message is calculated over the binary
payload data. That is, after any encryption enhancement has been
applied but before the message encoding is applied. This allows
messages to be converted from one encoding to another without
affecting signature verification.
Single Payload The signed value is the payload digest of the message
payload.
Multiple Payload. The signed value is the root of a Merkle Tree in
which the payload digest of the message is one of the leaves.
Verification of a multiple payload signature naturally requires the
additional digest values required to construct the Merkle Tree.
These are provided in the Trailer in a format that permits multiple
signers to reference the same tree data.
4. Algorithms
4.1. Field: kwd
The key wrapping and derivation algorithms.
Since the means of public key exchange is determined by the key
identifier of the recipient key, it is only necessary to specify the
algorithms used for key wrapping and derivation.
The default (and so far only) algorithm is kwd-aes-sha2-256-256.
Advanced Encryption Standard (AES) Key Wrap with Padding Algorithm
[RFC3394] is used to wrap the Master Exchange Key. AES 256 is used.
HMAC-based Extract-and-Expand Key Derivation Function [RFC5869] is
used for key derivation. SHA-2-256 is used for the hash function.
5. Reference
A DARE Message consists of a Header, an Enhanced Data Sequence (EDS)
and an optional trailer. This section describes the JSON data fields
used to construct headers, trailers and complete messages.
Hallam-Baker Expires February 28, 2019 [Page 16]
Internet-Draft DARE Message August 2018
Wherever possible, fields from JWE, JWS and JWK have been used. In
these cases, the fields have the exact same semantics. Note however
that the classes in which these fields are presented have different
structure and nesting.
5.1. Message Classes
A DARE Message contains a single DAREMessageSequence in either the
JSON or Compact serialization as directed by the protocol in which it
is applied.
5.1.1. Structure: DAREMessageSequence
A DARE Message containing Header, EDS and Trailer in JSON object
encoding. Since a DAREMessage is almost invariably presented in JSON
sequence or compact encoding, use of the DAREMessage subclass is
preferred.
Although a DARE Message is functionally an object, it is serialized
as an ordered sequence. This ensures that the message header field
will always precede the body in a serialization, this allowing
processing of the header information to be performed before the
entire body has been received.
Header: DAREHeader (Optional) The message header. May specify the
key exchange data, pre-signature or signature data, cloaked
headers and/or encrypted data sequences.
Body: Binary (Optional) The message body
Trailer: DARETrailer (Optional) The message trailer. If present,
this contains the signature.
5.2. Header and Trailer Classes
A DARE Message sequence MUST contain a (possibly empty) DAREHeader
and MAY contain a DARETrailer.
5.2.1. Structure: DARETrailer
A DARE Message Trailer
Signatures: DARESignature [0..Many] A list of signatures. A message
trailer MUST NOT contain a signatures field if the header contains
a signatures field.
Hallam-Baker Expires February 28, 2019 [Page 17]
Internet-Draft DARE Message August 2018
5.2.2. Structure: DAREHeader
Inherits: DARETrailer
A DARE Message Header. Since any field that is present in a trailer
MAY be placed in a header instead, the message header inherits from
the trailer.
EncryptionAlgorithm: String (Optional) The encryption algorithm as
specified in JWE
AuthenticationAlgorithm: String (Optional) Message Authentication
Code algorithm
Cloaked: Binary (Optional) If present in a header or trailer,
specifies an encrypted data block containing additional header
fields whose values override those specified in the message and
context headers.
When specified in a header, a cloaked field MAY be used to conceal
metadata (content type, compression) and/or to specify an
additional layer of key exchange. That applies to both the
Message body and to headers specified within the cloaked header.
Processing of cloaked data is described in?
ContentType: String (Optional) The content type field as specified
in JWE
EDSS: Binary [0..Many] If present, the Encrypted Data Segments field
contains a sequence of Encrypted Data Segments encrypted under the
message Master Key. The interpretation of these fields is
application specific.
Signers: DARESigner [0..Many] A list of 'presignature'
Recipients: DARERecipient [0..Many] A list of recipient key exchange
information blocks.
5.3. Cryptographic Data
DARE Message uses the same fields as JWE and JWS but with different
structure. In particular, DARE messages MAY have multiple recipients
and multiple signers.
Hallam-Baker Expires February 28, 2019 [Page 18]
Internet-Draft DARE Message August 2018
5.3.1. Structure: DARESigner
The signature value
Dig: String (Optional) Digest algorithm hint. Specifying the digest
algorithm to be applied to the message body allows the body to be
processed in streaming mode.
Alg: String (Optional) Key exchange algorithm
KeyIdentifier: String (Optional) Key identifier of the signature
key.
Certificate: X509Certificate (Optional) PKIX certificate of signer.
Path: X509Certificate (Optional) PKIX certificates that establish a
trust path for the signer.
5.3.2. Structure: X509Certificate
X5u: String (Optional) URL identifying an X.509 public key
certificate
X5: Binary (Optional) An X.509 public key certificate
5.3.3. Structure: DARESignature
Inherits: DARESigner
The signature value
SignatureValue: Binary (Optional) The signature value as an Enhanced
Data Sequence under the message Master Key.
5.3.4. Structure: DARERecipient
Recipient information
KeyIdentifier: String (Optional) Key identifier for the encryption
key.
The Key identifier MUST be either a UDF fingerprint of a key or a
Group Key Identifier
KeyWrapDerivation: String (Optional) The key wrapping and derivation
algorithms.
Hallam-Baker Expires February 28, 2019 [Page 19]
Internet-Draft DARE Message August 2018
WrappedMasterKey: Binary (Optional) The wrapped master key. The
master key is encrypted under the result of the key exchange.
RecipientKeyData: String (Optional) The per-recipient key exchange
data.
6. Security Considerations
6.1. Encryption/Signature nesting
6.2. Side channel
6.3. Salt reuse
7. IANA Considerations
8. Acknowledgements
9. Test Examples
In the following examples, Alice's encryption private key parameters
are:
{
"PrivateKeyDH":{
"kid":"MDAD3-E4BYE-MK6CH-QA2HD-TKRS2-KIX5Y-A",
"Domain":"YE6bnq1MlX5ojaJto6PLP_PEwA",
"Public":"GaMqeF8I2s00AUMm1D1dcXflA61rrbUflBbpYHLtz3GrwkVR_JsGd
qlCVWQEX9McxsYTJUoFJzeHivLsyoUlAY9H3Qtm_aClOeARO8yXboUTjKtwgH1qu0
s6kKl-p-tcaqu2PXReTVfOG9HtSR60iSuRZ9G9JHpKQNZCTdpoq4B2oBw6LvS1y-p
18bDCB_JeOOcqT8Aba08TjkhIG2OHaZDEgdDOU1nIAT1hIxh48sLuPSdou-F76l47
8Jte_oJKTqGCUUeOm_397_d4sbaCiPO0RMllIFC7VEhi2TIDL6bRF7ujmCdxreYn9
DlDjr1nF7hkcXEALL_5NyLVxwKdBw",
"Private":"cokgZSxP_IdDAswgUZWDFu6qlKrEVX83uwDU2jI5LWiIoknyE6dY
wW2_mADDQ_2DRxm73J3fTH6C73KAOx-cJnJYDqr8kU3FhBEXBn8wxFL6M-SgVxyKa
jZ5MRL0-3EAyNCAE_HLNoeUqAqGAchw-lnDgQO7e4F0hkEwa29JdwrBKTJxY93WAB
Xd3xZahbNWs3sh2MU_FGU6AzfnTWPdvWTTxImySVF47pex-gRbYFVV-Cm1ZUuof-5
flM-RwUlnf28qJ8SJ_-zKmjLc6TSrMky8ox1u6v7WHoFRiweMCyBQ3x2Zc2ypXPfF
DvvAu5RYiVoUbrlES1UswPObiE2lOg"}}
Figure 6
Alice's signature private key parameters are:
Hallam-Baker Expires February 28, 2019 [Page 20]
Internet-Draft DARE Message August 2018
{
"PrivateKeyRSA":{
"kid":"MBWNO-2J43U-ESWKW-XQWL6-6YGEW-UOPWU-A",
"n":"1NzbmakMalVH1mRv7TEDEhwXDNojn5wZbq1tv1gp5PgZwzX-klYXuFhj0-
MpO0zcwptsUaYJhwdvvgW_1udUpISQYluXOB3UMj2e_0yl64MvnqTL47SZQuAN3QQ
9cuCw_-_Eyj_jerspauqa6RpNzGcabZrtRl7J7DPVZ3SNlw-H_Wxd4HkrFVW_Yqup
htNL1JciQJYm2DSu9dbetqPZ80x6IBargY850mBYOzvNNE5S-dRJQHoJY4SG-ESYF
BuAHtBlOMgbI0XNiq96EegA-vPW9XRF-SHdX5mkafefDGK4rT_RoE4gRwhDM3jbZ8
1-F2ZA_GpNVEvB-25_vF96lQ",
"e":"AQAB",
"d":"k_v_h7Jo-TvUt44X6jSax-pTdBHrljk1zSYxGEe4yIBbmMVe-Gl2ECkTLe
nNbnafO4RGJ_Vgxkk7PEZO-p7Uz5OBtX-rf83tCgihEyg8aaFIZ-h1_xY9Pqr5uGA
MQGNJaoVMsLb99QNNZhE4JTquP56mVvDQaI3Zn6bhhA0ZqpxS_x6iRUV5KnHCRd47
DKGHcAsQR_caxGec7M_XNPqpl0tcoGQz46-I0SVVcqtjb_YysEVez4eJhb_ZTU4C7
pz4wXDj6B0ppFJVZEMaIhKo8FCnoQdXEJl4vSiBzUFrSlPc6gjQk2CBhxc_kb782w
VwW5wtgOVxhV1k2piQ2NrlOQ",
"p":"6osXfrJLiPfK0ky17vqzRs-M5mOxZU2LEFGyHTXxx6EYTWixEsx2Sdf6kx
UD5K_QdYnqqd3yobbGdDpMwwEuwgogWVCz90nc9QdCUy4MCpz8lpOQd1i_tXMmtOg
GBu9mapMTEOwc7HlLlSDRezv_TzTAH4izv-CUEZ_M5EcwyFM",
"q":"6FYD6NV4rKU1ACtGQyIvwGrkrS_F6phB-whx0nSVFkbkwppJiPnC6XqjZ3
OYPCZylxaTHFnxCs0nntrraeNEcWfNPrpTN5XIZjbOiIaKA2iCQkWlDoi8oduEtTK
oIcuy32oBz6MpUeCWzl0ZQ4EeTF3RyCc_jpf8oRvZ0e3ItHc",
"dp":"hfjbe9BmWx-HqCaPSanEW-9UQYmym_X2OGUiA5N7vxci5ZymgOFvs_B9v
iQj7C4NOgaEl3EjFgJsS5m9nSoAxm-4WKxDkD6NyxzRYugLkshnc69otvNn1kKnWn
CqeK2o57mJC4KDZwRGCzIK1oTH6jtsfta8Lh8fFQ4doEuV7uc",
"dq":"r6R_ViE0Foja1aLhflU09mmZMViBbkXm86nBqtHZ97pmrLvJRdVTxgCh0
c6w0yBZ1uEJHBDeykSoZE6qVCWtE3Le1kI0MTx6ANQENXBInCUA_Kr8Ck3TFSYIYJ
fIRaxiMMZKUjfOQAji2WXGeKL_TcpLkt4hDWLXaNDOTgdOiSc",
"qi":"DfHtLB1Ox1Kgp3E4jqy5Qxeb7-v7_uv8n_5-E1OQ3NLSRV2m_auojkR19
nY3gokHKNSXM41qKlJLU00lROjOO2KUq57s8GZkheVfbJLNCJ6KAw_aRT2IgyJm2b
e2v5OCHSkm88tgJWbtKj-OPKTFV5gOMVdeCzGX286ErjDHGCM"}}
Figure 7
The body of the test message is the UTF8 representation of the
following string:
"This is a test long enough to require multiple blocks"
Figure 8
The EDS sequences, are the UTF8 representation of the following
strings:
"Subject: Message metadata should be encrypted"
"2018-02-01"
Figure 9
Hallam-Baker Expires February 28, 2019 [Page 21]
Internet-Draft DARE Message August 2018
9.1. Plaintext Message
A plaintext message without associated EDS sequences is an empty
header followed by the message body:
{
"DAREMessage":[{},
"VGhpcyBpcyBhIHRlc3QgbG9uZyBlbm91Z2ggdG8gcmVxdWlyZSBtdWx0aXBsZS
BibG9ja3M"
]}
Figure 10
9.2. Plaintext Message with EDS
If a plaintext message contains EDS sequences, these are also in
plaintext:
{
"DAREMessage":[{
"Annotations":["iAEBiC1TdWJqZWN0OiBNZXNzYWdlIG1ldGFkYXRhIHNob3
VsZCBiZSBlbmNyeXB0ZWSIAA",
"iAECiAoyMDE4LTAyLTAxiAA"
]},
"VGhpcyBpcyBhIHRlc3QgbG9uZyBlbm91Z2ggdG8gcmVxdWlyZSBtdWx0aXBsZS
BibG9ja3M"
]}
Figure 11
9.3. Encrypted Message
The creator generates a master session key:
94 D7 0B C4 8C 43 B2 0E 7C 2A F8 C2 37 9C 8F E5
CA A7 8F BC 4C B3 9F CB 14 AA 5F 4C 41 AF 52 4B
Figure 12
The creator generates an ephemeral key:
Hallam-Baker Expires February 28, 2019 [Page 22]
Internet-Draft DARE Message August 2018
{
"PrivateKeyDH":{
"kid":"MAK3V-IOKWY-NFGD7-YBPY3-OWINU-3WRPC-A",
"Domain":"YE6bnq1MlX5ojaJto6PLP_PEwA",
"Public":"aeZpao1EpPIXrAFheMEHjjxJMucxpFJ5LvDXJunryv0xfpDseipYF
8jng0pBAE-P7CDPdw_WQgYDdW4NgF7BUbYq1EaXbcV1uLYBB2Yw2MAj-Up-7pO1Fc
5kjiDnRz0Sd0lJARCtkR5A2cuyMvuEg8cntCQWcoyzh4ep1PktlWDKoSKltovO0cM
-9hj-uGFiBV6-cb15fkQ7pyKp-XiH_2YkMCiUYhkPx9ZObr1WNMVHn9TyLgufPnLH
skaE2JDFckEBMljwXdI9z_DeUx4FNESRQQ68UGfDhfepPwR3_xbL9OFbFiJSjdd51
pxfzvi2SbJm8uKY5K3omsUMszyqjQA",
"Private":"iXfaIGr7vRVqJyTZEj_5F-3n7DL5KZzQ0sL4wydy1-F27A6kHjBW
yOrV0qr9BLuLRGH4vvfYSael_ILWzgKfC22KqN1CjJdzChwZvFyQCCXynrkH06KAk
uDWpczlC0n8T8WvTboalzVNvOfVM__QcywomDoY6tUCbIn6fQ5xJyWaR8EGQHPFdF
7W-O0ezKIieSKC25fIkIOt3c2-dqQdzUl2Vlk6R_6wkFxhX2NNqpV7VktrglQ6AUJ
b8gFt6H7gmsSvdks8lXv-1VHwwH_8HBRAOcqsRu9THuz8T4H30d30FZ-NXtCpUEwi
citGRXZ1UzmChc_IuIkfdQfuAGvttAA"}}
Figure 13
The key agreement value is calculated:
A2 CD 5A 08 24 70 27 5F 6F 28 A5 6D B0 AA 47 31
50 D0 F3 DA 07 13 4A 72 F7 BB 19 8E 72 60 82 51
32 0B CF 7B A1 8A FD 40 7E D5 E1 79 87 20 8B 2A
73 F5 20 2D 1C 94 FB 2D 8D 4F C0 DA 6D D7 C0 7A
D1 C6 35 A8 AD D2 DD BF F9 19 C3 BB 60 20 04 F7
D7 F0 81 F6 F3 94 68 DE 6F B6 B4 67 CD 9B F3 E4
A0 28 6E 59 5A A2 FE 00 10 17 B3 34 2C 07 20 06
2C B9 34 F0 4C C8 E9 C1 CA 80 1D 02 15 B6 CE D4
EC BB 91 2B FA 7D 9B 14 24 13 16 46 1C D2 5B 12
4A 0E 60 28 D6 38 E1 35 79 D6 DF 66 C0 C6 7F A7
E3 C1 9F 25 CD 01 A5 52 7A C1 B5 ED 3C 24 0F 8F
DD E6 27 60 F7 2D CF D5 7E 13 F8 29 53 7B 43 FC
13 F6 7B 55 8A 44 AD 16 A9 27 75 E0 9A DF 95 F6
F6 2C D5 26 88 1B EB 20 EE 26 C6 4E 17 20 54 BA
DB A5 37 A4 99 A2 FC 49 93 DE F5 8F F5 3B D1 F3
FF 9D 71 38 B1 AE 94 E0 10 61 16 CA 8F B9 16 1C
Figure 14
The key agreement value is used as the input to a HKDF key derivation
function with the info parameter System.Byte[] to create the key used
to wrap the master key:
Hallam-Baker Expires February 28, 2019 [Page 23]
Internet-Draft DARE Message August 2018
40 39 4F 58 34 F4 0F B3 AA 0F 88 7D EE AC 98 1A
91 84 25 3C 74 F6 E4 25 35 DB D6 78 6A ED 6B F5
Figure 15
The wrapped master key is:
14 98 FB 8C 0A D0 C8 C6 65 D3 9F F5 6B 80 42 96
0A 71 E9 93 F7 14 D2 29 C9 DB 96 FE FA 9A DB 74
29 F4 35 36 BC CF BF 41
Figure 16
This information is used to calculate the Recipient information shown
in the example below.
To encrypt a message, we first generate a unique salt value:
82 D1 8C BA A0 F0 26 5C 7A 35 5F 82 1F 88 35 CD
Figure 17
The salt value and master key are used to generate the payload
encryption key:
D3 74 4A 8E 69 65 A4 71 8B 14 44 AA CC E6 7F 66
07 87 91 3E F3 41 DE 2D DE 5F 4A 7C 19 D5 75 79
Figure 18
Since AES is a block cipher, we also require an initializarion
vector:
0A 5A 94 71 54 7B C2 16 E8 BF D2 66 5D 8D E5 BF
Figure 19
The output sequence is the encrypted bytes:
Hallam-Baker Expires February 28, 2019 [Page 24]
Internet-Draft DARE Message August 2018
30 33 D9 A1 12 19 EF 96 1C 43 45 98 50 7B D2 B1
A7 94 C2 C8 1B 52 00 3E DD A2 B4 9F 51 A5 BD 8C
F4 3D 81 15 95 D0 6D D7 19 5F 28 E3 A0 FF EA 26
29 27 78 B7 49 E7 B2 E3 AD A7 8C D1 C0 61 D5 68
Figure 20
Since the message is not signed, there is no need for a trailer. The
completed message is:
{
"DAREMessage":[{
"enc":"A256CBC",
"Salt":"gtGMuqDwJlx6NV-CH4g1zQ",
"recipients":[{
"kid":"MDAD3-E4BYE-MK6CH-QA2HD-TKRS2-KIX5Y-A",
"epk":{
"PublicKeyDH":{
"kid":"MAK3V-IOKWY-NFGD7-YBPY3-OWINU-3WRPC-A",
"Domain":"YE6bnq1MlX5ojaJto6PLP_PEwA",
"Public":"aeZpao1EpPIXrAFheMEHjjxJMucxpFJ5LvDXJunryv0
xfpDseipYF8jng0pBAE-P7CDPdw_WQgYDdW4NgF7BUbYq1EaXbcV1uLYBB2Yw2MAj
-Up-7pO1Fc5kjiDnRz0Sd0lJARCtkR5A2cuyMvuEg8cntCQWcoyzh4ep1PktlWDKo
SKltovO0cM-9hj-uGFiBV6-cb15fkQ7pyKp-XiH_2YkMCiUYhkPx9ZObr1WNMVHn9
TyLgufPnLHskaE2JDFckEBMljwXdI9z_DeUx4FNESRQQ68UGfDhfepPwR3_xbL9OF
bFiJSjdd51pxfzvi2SbJm8uKY5K3omsUMszyqjQA"}},
"wmk":"FJj7jArQyMZl05_1a4BClgpx6ZP3FNIpyduW_vqa23Qp9DU2vM
-_QQ"}
]},
"MDPZoRIZ75YcQ0WYUHvSsaeUwsgbUgA-3aK0n1GlvYz0PYEVldBt1xlfKOOg_-
omKSd4t0nnsuOtp4zRwGHVaA"
]}
Figure 21
9.4. Signed Message
Signed messages specify the digest algorithm to be used in the header
and the signature value in the trailer. Note that the digest
algorithm is not optional since it serves as notice that a decoder
should digest the payload value to enable signature verification.
Hallam-Baker Expires February 28, 2019 [Page 25]
Internet-Draft DARE Message August 2018
{
"DAREMessage":[{
"dig":"S512"},
"VGhpcyBpcyBhIHRlc3QgbG9uZyBlbm91Z2ggdG8gcmVxdWlyZSBtdWx0aXBsZS
BibG9ja3M",
{
"signatures":[{
"signature":"s4LxUqNOV1-0uryJCiYFqnKak3EHZuLBaaUrehaRCaZH
2KqASBftk87fTl73XUeV-0TfvlfV8STP7l0brcWnPTKQgXSMXvuoxqF0n9qcpXubB
xzdGHdFX-5GeQMFsr8NutBBng-LSZVe2eCb7n29dpCgZ84v5Y4JGzvKHOy8vaU"}
],
"PayloadDigest":"raim8SV5adPbWWn8FMM4mrRAQCO9A2jZ0NZAnFXWlG0x
F6sWGJbnKSdtIJMmMU_hjarlIPEoY3vy9UdVlH5KAg"}
]}
Figure 22
9.5. Signed and Encrypted Message
A signed and encrypted message is encrypted and then signed. The
signer proves knowledge of the payload plaintext by providing the
plaintext witness value.
Hallam-Baker Expires February 28, 2019 [Page 26]
Internet-Draft DARE Message August 2018
{
"DAREMessage":[{
"enc":"A256CBC",
"dig":"S512",
"Salt":"AB4x8M6bLZjdSr6W9ntB2A",
"recipients":[{
"kid":"MDAD3-E4BYE-MK6CH-QA2HD-TKRS2-KIX5Y-A",
"epk":{
"PublicKeyDH":{
"kid":"MDJLN-DFSIO-ZOL6P-2NOZD-YHBQH-3JQSK-A",
"Domain":"YE6bnq1MlX5ojaJto6PLP_PEwA",
"Public":"XBYmS2ui9AgETUvwK9d3eLWQiQ8240yddATCETYAAUH
H0m29aDiBpIT9TcDVs6dtnWH-mnZMTfwT_RQJvyMcfM1AYFvmMfu3GoFS6Z4nngor
hZGFNGgWEG7yX9eOvaiBWpTs2gw7AM4PvUh9r5G0IolfIvQcTRZHpKuU3GqV0E0xp
PhrEajKzLSrDNu6tZ2yDe7BQBSI7YNgZGeXqOTr3KmfdfYU7Hk_ak3M_LhtCCe2-m
bwPuDUD0PUWScZLrKbMWzLIzO0OrDYMwjSrJmirH2RxQKM2a_kJAQoBFtmXjlaFLC
yvOKK1ibPnWn7_JZtUy_k4IvDex6b7VKVap6ySQ"}},
"wmk":"qS1rvoKhPjlVy3B6uYkgRYYTJtOzDEeiqqezpTAoGh8Op2VV6x
cbUw"}
]},
"MudZFUAZRBINTZO9szFJCr9NUrE1s1meuZfRftorYK5_gI8-NAjLud8Jx8LM_R
DVNXfi5GKGNFuvfr0MlqyFRQ",
{
"signatures":[{
"signature":"SAzZxGhqUVUSQCta3vZ1OL9AkdLD40sVSE9k2opol_FW
4aEyMEm4c5UZTnkf6Ndkz1O47TrjHowzagSwkTdq-dV7r7OxH-oQ9fTeG1GyT8xwo
Yw4KsSjD71X_lwgi2BI-WMvdVliOFk78MC52eF7SsA0mkbWnSSB0WHBjoJvEaI",
"witness":"zvxEBQmdHJCin9brH4lpD-8CNJXWezsSMhWAT-CSlk0"}
],
"PayloadDigest":"ScoVguz7ufoe547gh9LIC00ptI24ZzpwLplJFzeJQx9d
G7LfeBTi2oNPr2GBuLp29pRRuDqgdRCftuLeRBl8kg"}
]}
Figure 23
10. References
10.1. Normative References
[draft-hallambaker-jsonbcd]
Hallam-Baker, P., "Binary Encodings for JavaScript Object
Notation: JSON-B, JSON-C, JSON-D", draft-hallambaker-
jsonbcd-13 (work in progress), July 2018.
[draft-hallambaker-udf]
Hallam-Baker, P., "Uniform Data Fingerprint (UDF)", draft-
hallambaker-udf-10 (work in progress), April 2018.
Hallam-Baker Expires February 28, 2019 [Page 27]
Internet-Draft DARE Message August 2018
[IANAJOSE]
"[Reference Not Found!]".
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997.
[RFC2315] Kaliski, B., "PKCS #7: Cryptographic Message Syntax
Version 1.5", RFC 2315, DOI 10.17487/RFC2315, March 1998.
[RFC3394] Schaad, J. and R. Housley, "Advanced Encryption Standard
(AES) Key Wrap Algorithm", RFC 3394, DOI 10.17487/RFC3394,
September 2002.
[RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R.
Thayer, "OpenPGP Message Format", RFC 4880,
DOI 10.17487/RFC4880, November 2007.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007.
[RFC5869] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
Key Derivation Function (HKDF)", RFC 5869,
DOI 10.17487/RFC5869, May 2010.
[RFC7159] Bray, T., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
RFC 7516, DOI 10.17487/RFC7516, May 2015.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015.
10.2. Informative References
[Davis2001]
Davis, D., "Defective Sign & Encrypt in S/MIME, PKCS#7,
MOSS, PEM, PGP, and XML", May 2001.
Hallam-Baker Expires February 28, 2019 [Page 28]
Internet-Draft DARE Message August 2018
10.3. URIs
[1] http://mathmesh.com/Documents/draft-hallambaker-dare-message.html
[2] http://mathmesh.com/Documents/draft-hallambaker-dare-message.html
[3] http://mathmesh.com/Documents/draft-hallambaker-dare-message.html
[4] http://mathmesh.com/Documents/draft-hallambaker-dare-message.html
Author's Address
Phillip Hallam-Baker
Comodo Group Inc.
Email: philliph@comodo.com
Hallam-Baker Expires February 28, 2019 [Page 29]
