Internet DRAFT - draft-ietf-tls-oob-pubkey
draft-ietf-tls-oob-pubkey
TLS P. Wouters, Ed.
Internet-Draft Red Hat
Intended status: Standards Track H. Tschofenig, Ed.
Expires: July 22, 2014
J. Gilmore
S. Weiler
SPARTA, Inc.
T. Kivinen
AuthenTec
January 18, 2014
Using Raw Public Keys in Transport Layer Security (TLS) and Datagram
Transport Layer Security (DTLS)
draft-ietf-tls-oob-pubkey-11.txt
Abstract
This document specifies a new certificate type and two TLS extensions
for exchanging raw public keys in Transport Layer Security (TLS) and
Datagram Transport Layer Security (DTLS). The new certificate type
allows raw public keys to be used for authentication.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 22, 2014.
Copyright Notice
Copyright (c) 2014 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Structure of the Raw Public Key Extension . . . . . . . . . . 4
4. TLS Client and Server Handshake Behavior . . . . . . . . . . 6
4.1. Client Hello . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Server Hello . . . . . . . . . . . . . . . . . . . . . . 8
4.3. Client Authentication . . . . . . . . . . . . . . . . . . 9
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. TLS Server uses Raw Public Key . . . . . . . . . . . . . 9
5.2. TLS Client and Server use Raw Public Keys . . . . . . . . 10
5.3. Combined Usage of Raw Public Keys and X.509 Certificate . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . 15
Appendix A. Example Encoding . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
Traditionally, TLS client and server public keys are obtained in PKIX
containers in-band as part of the TLS handshake procedure and are
validated using trust anchors based on a [PKIX] certification
authority (CA). This method can add a complicated trust relationship
that is difficult to validate. Examples of such complexity can be
seen in [Defeating-SSL]. TLS is, however, also commonly used with
self-signed certificates in smaller deployments where the self-signed
certificates are distributed to all involved protocol end points out-
of-band. This practice does, however, still requires the overhead of
the certificate generation even though none of the information found
in the certificate is actually used.
Alternative methods are available that allow a TLS client/server to
obtain the TLS server/client public key:
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o The TLS client can obtain the TLS server public key from a DNSSEC
secured resource records using DANE [RFC6698].
o The TLS client or server public key is obtained from a [PKIX]
certificate chain from an Lightweight Directory Access Protocol
(LDAP) [LDAP] server or web page.
o The TLS client and server public key is provisioned into the
operating system firmware image, and updated via software updates.
For example:
Some smart objects use the UDP-based Constrained Application
Protocol (CoAP) [I-D.ietf-core-coap] to interact with a Web server
to upload sensor data at a regular intervals, such as temperature
readings. CoAP can utilize DTLS for securing the client-to-server
communication. As part of the manufacturing process, the embedded
device may be configured with the address and the public key of a
dedicated CoAP server, as well as a public/private key pair for
the client itself.
This document introduces the use of raw public keys in TLS/DTLS.
With raw public keys, only a subset of the information found in
typical certificates is utilized: namely, the SubjectPublicKeyInfo
structure of a PKIX certificates that carries the parameters
necessary to describe the public key. Other parameters found in PKIX
certificates are omitted. By omitting various certificate-related
structures, the resulting raw public key is kept fairly small in
comparison to the original certificate, and the code to process the
keys requires only a minimalistic ASN.1 parser, no code for
certificate path validation, and other PKIX related processing tasks
are also omitted. Note, however, the SubjectPublicKeyInfo structure
is still in an ASN.1 format. To further reduce the size of the
exchanged information this specification can be combined with the TLS
Cached Info extension [I-D.ietf-tls-cached-info], which enables TLS
peers to just exchange fingerprints of their public keys.
The mechanism defined herein only provides authentication when an
out-of-band mechanism is also used to bind the public key to the
entity presenting the key.
Section 3 defines the structure of the two new TLS extensions
"client_certificate_type" and "server_certificate_type", which can be
used as part of an extended TLS handshake when raw public keys are to
be used. Section 4 defines the behavior of the TLS client and the
TLS server. Example exchanges are described in Section 5. Section 6
describes security considerations with this approach. Finally, in
Section 7 this document also registers a new value to the IANA
certificate types registry for the support of raw public keys.
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2. Terminology
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 RFC 2119 [RFC2119].
We use the terms 'TLS server' and 'server' as well as 'TLS client'
and 'client' interchangable.
3. Structure of the Raw Public Key Extension
This section defines the two TLS extensions 'client_certificate_type'
and 'server_certificate_type', which can be used as part of an
extended TLS handshake when raw public keys are used. Section 4
defines the behavior of the TLS client and the TLS server using this
extension.
This specification uses raw public keys whereby the already available
encoding used in a PKIX certificate in the form of a
SubjectPublicKeyInfo structure is reused. To carry the raw public
key within the TLS handshake the Certificate payload is used as a
container, as shown in Figure 1. The shown Certificate structure is
an adaptation of its original form [RFC5246].
opaque ASN.1Cert<1..2^24-1>;
struct {
select(certificate_type){
// certificate type defined in this document.
case RawPublicKey:
opaque ASN.1_subjectPublicKeyInfo<1..2^24-1>;
// X.509 certificate defined in RFC 5246
case X.509:
ASN.1Cert certificate_list<0..2^24-1>;
// Additional certificate type based on TLS
// Certificate Type Registry
};
} Certificate;
Figure 1: Certificate Payload as a Container for the Raw Public Key.
The SubjectPublicKeyInfo structure is defined in Section 4.1 of RFC
5280 [PKIX] and does not only contain the raw keys, such as the
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public exponent and the modulus of an RSA public key, but also an
algorithm identifier. The algorithm identifier can also include
parameters. The SubjectPublicKeyInfo value in the Certificate
payload MUST contain the DER encoding [X.690] of the
SubjectPublicKeyInfo. The structure, as shown in Figure 2, therefore
also contains length information as well. An example is provided in
Appendix A.
SubjectPublicKeyInfo ::= SEQUENCE {
algorithm AlgorithmIdentifier,
subjectPublicKey BIT STRING }
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL }
Figure 2: SubjectPublicKeyInfo ASN.1 Structure.
The algorithm identifiers are Object Identifiers (OIDs). RFC 3279
[RFC3279] and [RFC5480], for example, define the following OIDs shown
in Figure 3. Note that this list is not exhaustive and more OIDs may
be defined in future RFCs. RFC 5480 also defines a number of OIDs.
Key Type | Document | OID
-----------------------+----------------------------+-------------------
RSA | Section 2.3.1 of RFC 3279 | 1.2.840.113549.1.1
.......................|............................|...................
Digital Signature | |
Algorithm (DSA) | Section 2.3.2 of RFC 3279 | 1.2.840.10040.4.1
.......................|............................|...................
Elliptic Curve | |
Digital Signature | |
Algorithm (ECDSA) | Section 2 of RFC 5480 | 1.2.840.10045.2.1
-----------------------+----------------------------+-------------------
Figure 3: Example Algorithm Object Identifiers.
The extension format for extended client and server hellos, which
uses the "extension_data" field, is used to carry the
ClientCertTypeExtension and the ServerCertTypeExtension structures.
These two structures are shown in Figure 4. The CertificateType
structure is an enum with values taken from the 'TLS Certificate
Type' registry [TLS-Certificate-Types-Registry].
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struct {
select(ClientOrServerExtension) {
case client:
CertificateType client_certificate_types<1..2^8-1>;
case server:
CertificateType client_certificate_type;
}
} ClientCertTypeExtension;
struct {
select(ClientOrServerExtension) {
case client:
CertificateType server_certificate_types<1..2^8-1>;
case server:
CertificateType server_certificate_type;
}
} ServerCertTypeExtension;
Figure 4: CertTypeExtension Structure.
4. TLS Client and Server Handshake Behavior
This specification extends the ClientHello and the ServerHello
messages, according to the extension procedures defined in [RFC5246].
It does not extend or modify any other TLS message.
Note: No new cipher suites are required to use raw public keys. All
existing cipher suites that support a key exchange method compatible
with the defined extension can be used.
The high-level message exchange in Figure 5 shows the
'client_certificate_type' and 'server_certificate_type' extensions
added to the client and server hello messages.
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client_hello,
client_certificate_type,
server_certificate_type ->
<- server_hello,
client_certificate_type,
server_certificate_type,
certificate,
server_key_exchange,
certificate_request,
server_hello_done
certificate,
client_key_exchange,
certificate_verify,
change_cipher_spec,
finished ->
<- change_cipher_spec,
finished
Application Data <-------> Application Data
Figure 5: Basic Raw Public Key TLS Exchange.
4.1. Client Hello
In order to indicate the support of raw public keys, clients include
the 'client_certificate_type' and/or the 'server_certificate_type'
extensions in an extended client hello message. The hello extension
mechanism is described in Section 7.4.1.4 of TLS 1.2 [RFC5246].
The 'client_certificate_type' in the client hello indicates the
certificate types the client is able to provide to the server, when
requested using a certificate_request message.
The 'server_certificate_type' in the client hello indicates the types
of certificates the client is able to process when provided by the
server in a subsequent certificate payload.
The 'client_certificate_type' and 'server_certificate_type' sent in
the client hello may carry a list of supported certificate types,
sorted by client preference. It is a list in the case where the
client supports multiple certificate types.
The TLS client MUST omit the 'client_certificate_type' extension in
the client hello if it does not possess a raw public key/certificate
that it can provide to the server when requested using a
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certificate_request message or is not configured to use one with the
given TLS server. The TLS client MUST omit the
'server_certificate_type' extension in the client hello if it is
unable to process raw public keys or other certificate types
introduced via this extension.
4.2. Server Hello
If the server receives a client hello that contains the
'client_certificate_type' extension and/or the
'server_certificate_type' extension then three outcomes are possible:
1. The server does not support the extension defined in this
document. In this case the server returns the server hello
without the extensions defined in this document.
2. The server supports the extension defined in this document but it
does not have any certificate type in common with the client.
Then, the server terminates the session with a fatal alert of
type "unsupported_certificate".
3. The server supports the extensions defined in this document and
has at least one certificate type in common with the client. In
this case the processing rules described below are followed.
The 'client_certificate_type' in the client hello indicates the
certificate types the client is able to provide to the server, when
requested using a certificate_request message. If the TLS server
wants to request a certificate from the client (via the
certificate_request message) it MUST include the
'client_certificate_type' extension in the server hello. This
'client_certificate_type' in the server hello then indicates the type
of certificates the client is requested to provide in a subsequent
certificate payload. The value conveyed in the
'client_certificate_type' MUST be selected from one of the values
provided in the 'client_certificate_type' extension sent in the
client hello. The server MUST also include a certificate_request
payload in the server hello message.
If the server does not send a certificate_request payload (for
example, because client authentication happens at the application
layer or no client authentication is required) or none of the
certificates supported by the client (as indicated in the
'client_certificate_type' in the client hello) match the server-
supported certificate types then the 'client_certificate_type'
payload in the server hello MUST be omitted.
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The 'server_certificate_type' in the client hello indicates the types
of certificates the client is able to process when provided by the
server in a subsequent certificate payload. If the client hello
indicates support of raw public keys in the 'server_certificate_type'
extension and the server chooses to use raw public keys then the TLS
server MUST place the SubjectPublicKeyInfo structure into the
Certificate payload. With the 'server_certificate_type' in the
server hello the TLS server indicates the certificate type carried in
the Certificate payload. This additional indication allows to avoid
parsing ambiguities since the Certificate payload may contain either
the X.509 certificate or a SubjectPublicKeyInfo structure. Note that
only a single value is permitted in the 'server_certificate_type'
extension when carried in the server hello.
4.3. Client Authentication
Authentication of the TLS client to the TLS server is supported only
through authentication of the received client SubjectPublicKeyInfo
via an out-of-band method.
5. Examples
Figure 6, Figure 7, and Figure 8 illustrate example exchanges. Note
that TLS ciphersuites using a Diffie-Hellman exchange offering
forward secrecy can be used with raw public keys although we do not
show the information exchange at that level with the subsequent
message flows.
5.1. TLS Server uses Raw Public Key
This section shows an example where the TLS client indicates its
ability to receive and validate raw public keys from the server. In
our example the client is quite restricted since it is unable to
process other certificate types sent by the server. It also does not
have credentials at the TLS layer it could send to the server and
therefore omits the 'client_certificate_type' extension. Hence, the
client only populates the 'server_certificate_type' extension with
the raw public key type, as shown in [1].
When the TLS server receives the client hello it processes the
extension. Since it has a raw public key it indicates in [2] that it
had chosen to place the SubjectPublicKeyInfo structure into the
Certificate payload [3].
The client uses this raw public key in the TLS handshake together
with an out-of-band validation technique, such as DANE, to verify it.
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client_hello,
server_certificate_type=(RawPublicKey) // [1]
->
<- server_hello,
server_certificate_type=(RawPublicKey), // [2]
certificate, // [3]
server_key_exchange,
server_hello_done
client_key_exchange,
change_cipher_spec,
finished ->
<- change_cipher_spec,
finished
Application Data <-------> Application Data
Figure 6: Example with Raw Public Key provided by the TLS Server.
5.2. TLS Client and Server use Raw Public Keys
This section shows an example where the TLS client as well as the TLS
server use raw public keys. This is one of the use case envisioned
for smart object networking. The TLS client in this case is an
embedded device that is configured with a raw public key for use with
TLS and is also able to process raw public keys sent by the server.
Therefore, it indicates these capabilities in [1]. As in the
previously shown example the server fulfills the client's request,
indicates this via the "RawPublicKey" value in the
server_certificate_type payload [2], and provides a raw public key
into the Certificate payload back to the client (see [3]). The TLS
server, however, demands client authentication and therefore a
certificate_request is added [4]. The certificate_type payload in
[5] indicates that the TLS server accepts raw public keys. The TLS
client, who has a raw public key pre-provisioned, returns it in the
Certificate payload [6] to the server.
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client_hello,
client_certificate_type=(RawPublicKey) // [1]
server_certificate_type=(RawPublicKey) // [1]
->
<- server_hello,
server_certificate_type=(RawPublicKey)//[2]
certificate, // [3]
client_certificate_type=(RawPublicKey)//[5]
certificate_request, // [4]
server_key_exchange,
server_hello_done
certificate, // [6]
client_key_exchange,
change_cipher_spec,
finished ->
<- change_cipher_spec,
finished
Application Data <-------> Application Data
Figure 7: Example with Raw Public Key provided by the TLS Server and
the Client.
5.3. Combined Usage of Raw Public Keys and X.509 Certificate
This section shows an example combining raw public keys and X.509
certificates. The client uses a raw public key for client
authentication and the server provides an X.509 certificate. This
exchange starts with the client indicating its ability to process
X.509 certificates and raw public keys, if provided by the server.
Additionally, the client indicates that is has a raw public key for
client-side authentication (see [1]). The server provides the X.509
certificate in [3] with the indication present in [2]. For client
authentication the server indicates in [4] that it selected the raw
public key format and requests a certificate from the client in [5].
The TLS client provides a raw public key in [6] after receiving and
processing the TLS server hello message.
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client_hello,
server_certificate_type=(X.509, RawPublicKey)
client_certificate_type=(RawPublicKey) // [1]
->
<- server_hello,
server_certificate_type=(X.509)//[2]
certificate, // [3]
client_certificate_type=(RawPublicKey)//[4]
certificate_request, // [5]
server_key_exchange,
server_hello_done
certificate, // [6]
client_key_exchange,
change_cipher_spec,
finished ->
<- change_cipher_spec,
finished
Application Data <-------> Application Data
Figure 8: Hybrid Certificate Example.
6. Security Considerations
The transmission of raw public keys, as described in this document,
provides benefits by lowering the over-the-air transmission overhead
since raw public keys are naturally smaller than an entire
certificate. There are also advantages from a code size point of
view for parsing and processing these keys. The cryptographic
procedures for associating the public key with the possession of a
private key also follows standard procedures.
The main security challenge is, however, how to associate the public
key with a specific entity. Without a secure binding between
identifier and key, the protocol will be vulnerable to man-in-the-
middle attacks. This document assumes that such binding can be made
out-of-band and we list a few examples in Section 1. DANE [RFC6698]
offers one such approach. In order to address these vulnerabilities,
specifications that make use of the extension need to specify how the
identifier and public key are bound. In addition to ensuring the
binding is done out-of-band an implementation also needs to check the
status of that binding.
If public keys are obtained using DANE, these public keys are
authenticated via DNSSEC. Pre-configured keys is another out-of-band
method for authenticating raw public keys. While pre-configured keys
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are not suitable for a generic Web-based e-commerce environment such
keys are a reasonable approach for many smart object deployments
where there is a close relationship between the software running on
the device and the server-side communication endpoint. Regardless of
the chosen mechanism for out-of-band public key validation an
assessment of the most suitable approach has to be made prior to the
start of a deployment to ensure the security of the system.
An attacker might try to influence the handshake exchange to make the
parties select different certificate types than they would normally
choose.
For this attack, an attacker must actively change one or more
handshake messages. If this occurs, the client and server will
compute different values for the handshake message hashes. As a
result, the parties will not accept each others' Finished messages.
Without the master_secret, the attacker cannot repair the Finished
messages, so the attack will be discovered.
7. IANA Considerations
IANA is asked to register a new value in the "TLS Certificate Types"
registry of Transport Layer Security (TLS) Extensions
[TLS-Certificate-Types-Registry], as follows:
Value: 2
Description: Raw Public Key
Reference: [[THIS RFC]]
This document asks IANA to allocate two new TLS extensions,
"client_certificate_type" and "server_certificate_type", from the TLS
ExtensionType registry defined in [RFC5246]. These extensions are
used in both the client hello message and the server hello message.
The new extension type is used for certificate type negotiation. The
values carried in these extensions are taken from the TLS Certificate
Types registry [TLS-Certificate-Types-Registry].
8. Acknowledgements
The feedback from the TLS working group meeting at IETF#81 has
substantially shaped the document and we would like to thank the
meeting participants for their input. The support for hashes of
public keys has been moved to [I-D.ietf-tls-cached-info] after the
discussions at the IETF#82 meeting.
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We would like to thank the following persons for their review
comments: Martin Rex, Bill Frantz, Zach Shelby, Carsten Bormann,
Cullen Jennings, Rene Struik, Alper Yegin, Jim Schaad, Barry Leiba,
Paul Hoffman, Robert Cragie, Nikos Mavrogiannopoulos, Phil Hunt, John
Bradley, Klaus Hartke, Stefan Jucker, Kovatsch Matthias, Daniel Kahn
Gillmor, Peter Sylvester, Hauke Mehrtens, Alexey Melnikov, Stephen
Farrell, Richard Barnes, and James Manger. Nikos Mavrogiannopoulos
contributed the design for re-using the certificate type registry.
Barry Leiba contributed guidance for the IANA consideration text.
Stefan Jucker, Kovatsch Matthias, and Klaus Hartke provided
implementation feedback regarding the SubjectPublicKeyInfo structure.
Christer Holmberg provided the General Area (Gen-Art) review, Yaron
Sheffer provided the Security Directorate (SecDir) review, Bert
Greevenbosch provided the Applications Area Directorate review, and
Linda Dunbar provided the Operations Directorate review.
We would like to thank our TLS working group chairs, Eric Rescorla
and Joe Salowey, for their guidance and support. Finally, we would
like to thank Sean Turner, who is the responsible security area
director for this work for his review comments and suggestions.
9. References
9.1. Normative References
[PKIX] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 3279, April 2002.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
"Elliptic Curve Cryptography Subject Public Key
Information", RFC 5480, March 2009.
[TLS-Certificate-Types-Registry]
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"TLS Certificate Types Registry", February 2013,
<http://www.iana.org/assignments/
tls-extensiontype-values#tls-extensiontype-values-2>.
[X.690] "Information technology - ASN.1 encoding rules: >
Specification of Basic Encoding Rules (BER), Canonical >
Encoding Rules (CER) and Distinguished Encoding Rules >
(DER).", RFC 5280, 2002.
9.2. Informative References
[ASN.1-Dump]
Gutmann, P., "ASN.1 Object Dump Program", February 2013,
<http://www.cs.auckland.ac.nz/~pgut001/>.
[Defeating-SSL]
Marlinspike, M., "New Tricks for Defeating SSL in
Practice", February 2009, <http://www.blackhat.com/
presentations/bh-dc-09/Marlinspike/
BlackHat-DC-09-Marlinspike-Defeating-SSL.pdf>.
[I-D.ietf-core-coap]
Shelby, Z., Hartke, K., and C. Bormann, "Constrained
Application Protocol (CoAP)", draft-ietf-core-coap-18
(work in progress), June 2013.
[I-D.ietf-tls-cached-info]
Santesson, S. and H. Tschofenig, "Transport Layer Security
(TLS) Cached Information Extension", draft-ietf-tls-
cached-info-15 (work in progress), October 2013.
[LDAP] Sermersheim, J., "Lightweight Directory Access Protocol
(LDAP): The Protocol", RFC 4511, June 2006.
[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
of Named Entities (DANE) Transport Layer Security (TLS)
Protocol: TLSA", RFC 6698, August 2012.
Appendix A. Example Encoding
For example, the hex sequence shown in Figure 9 describes a
SubjectPublicKeyInfo structure inside the certificate payload.
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0 1 2 3 4 5 6 7 8 9
+------+-----+-----+-----+-----+-----+-----+-----+-----+-----
1 | 0x30, 0x81, 0x9f, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48,
2 | 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05, 0x00, 0x03, 0x81,
3 | 0x8d, 0x00, 0x30, 0x81, 0x89, 0x02, 0x81, 0x81, 0x00, 0xcd,
4 | 0xfd, 0x89, 0x48, 0xbe, 0x36, 0xb9, 0x95, 0x76, 0xd4, 0x13,
5 | 0x30, 0x0e, 0xbf, 0xb2, 0xed, 0x67, 0x0a, 0xc0, 0x16, 0x3f,
6 | 0x51, 0x09, 0x9d, 0x29, 0x2f, 0xb2, 0x6d, 0x3f, 0x3e, 0x6c,
7 | 0x2f, 0x90, 0x80, 0xa1, 0x71, 0xdf, 0xbe, 0x38, 0xc5, 0xcb,
8 | 0xa9, 0x9a, 0x40, 0x14, 0x90, 0x0a, 0xf9, 0xb7, 0x07, 0x0b,
9 | 0xe1, 0xda, 0xe7, 0x09, 0xbf, 0x0d, 0x57, 0x41, 0x86, 0x60,
10 | 0xa1, 0xc1, 0x27, 0x91, 0x5b, 0x0a, 0x98, 0x46, 0x1b, 0xf6,
11 | 0xa2, 0x84, 0xf8, 0x65, 0xc7, 0xce, 0x2d, 0x96, 0x17, 0xaa,
12 | 0x91, 0xf8, 0x61, 0x04, 0x50, 0x70, 0xeb, 0xb4, 0x43, 0xb7,
13 | 0xdc, 0x9a, 0xcc, 0x31, 0x01, 0x14, 0xd4, 0xcd, 0xcc, 0xc2,
14 | 0x37, 0x6d, 0x69, 0x82, 0xd6, 0xc6, 0xc4, 0xbe, 0xf2, 0x34,
15 | 0xa5, 0xc9, 0xa6, 0x19, 0x53, 0x32, 0x7a, 0x86, 0x0e, 0x91,
16 | 0x82, 0x0f, 0xa1, 0x42, 0x54, 0xaa, 0x01, 0x02, 0x03, 0x01,
17 | 0x00, 0x01
Figure 9: Example SubjectPublicKeyInfo Structure Byte Sequence.
The decoded byte-sequence shown in Figure 9 (for example using
Peter's ASN.1 decoder [ASN.1-Dump]) illustrates the structure, as
shown in Figure 10.
Offset Length Description
-------------------------------------------------------------------
0 3+159: SEQUENCE {
3 2+13: SEQUENCE {
5 2+9: OBJECT IDENTIFIER Value (1 2 840 113549 1 1 1)
: PKCS #1, rsaEncryption
16 2+0: NULL
: }
18 3+141: BIT STRING, encapsulates {
22 3+137: SEQUENCE {
25 3+129: INTEGER Value (1024 bit)
157 2+3: INTEGER Value (65537)
: }
: }
: }
Figure 10: Decoding of Example SubjectPublicKeyInfo Structure.
Wouters, et al. Expires July 22, 2014 [Page 16]
Internet-Draft Using Raw Public Keys in TLS/DTLS January 2014
Authors' Addresses
Paul Wouters (editor)
Red Hat
Email: paul@nohats.ca
Hannes Tschofenig (editor)
Cambridge CBI 9NJ
UK
Email: Hannes.Tschofenig@gmx.net
URI: http://www.tschofenig.priv.at
John Gilmore
PO Box 170608
San Francisco, California 94117
USA
Phone: +1 415 221 6524
Email: gnu@toad.com
URI: https://www.toad.com/
Samuel Weiler
SPARTA, Inc.
7110 Samuel Morse Drive
Columbia, Maryland 21046
US
Email: weiler@tislabs.com
Tero Kivinen
AuthenTec
Eerikinkatu 28
HELSINKI FI-00180
FI
Email: kivinen@iki.fi
Wouters, et al. Expires July 22, 2014 [Page 17]
