Internet DRAFT - draft-altman-tls-channel-bindings
draft-altman-tls-channel-bindings
NETWORK WORKING GROUP J. Altman
Internet-Draft Secure Endpoints
Intended status: Standards Track N. Williams
Expires: October 1, 2010 Oracle
L. Zhu
Microsoft Corporation
March 30, 2010
Channel Bindings for TLS
draft-altman-tls-channel-bindings-10.txt
Abstract
This document defines three channel binding types for Transport Layer
Security (TLS), tls-unique, tls-server-end-point, and tls-unique-for-
telnet, in accordance with RFC 5056 (On Channel Binding).
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on October 1, 2010.
Copyright Notice
Copyright (c) 2010 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
Altman, et al. Expires October 1, 2010 [Page 1]
Internet-Draft TLS Channel Bindings March 2010
(http://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
the Trust Legal Provisions and are provided without warranty as
described in the BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Altman, et al. Expires October 1, 2010 [Page 2]
Internet-Draft TLS Channel Bindings March 2010
Table of Contents
1. Conventions used in this document . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
3. The 'tls-unique' Channel Binding Type . . . . . . . . . . . 5
3.1. Description . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Registration . . . . . . . . . . . . . . . . . . . . . . . . 6
4. The 'tls-server-end-point' Channel Binding Type . . . . . . 7
4.1. Description . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Registration . . . . . . . . . . . . . . . . . . . . . . . . 7
5. The 'tls-unique-for-telnet' Channel Binding Type . . . . . . 9
5.1. Description . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2. Registration . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Applicability of TLS Channel Binding Types . . . . . . . . . 11
7. Required Application Programming Interfaces . . . . . . . . 14
8. Description of backwards-incompatible changes made
herein to 'tls-unique' . . . . . . . . . . . . . . . . . . . 15
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . 16
10. Security Considerations . . . . . . . . . . . . . . . . . . 17
10.1. Cryptographic Algorithm Agility . . . . . . . . . . . . . . 17
10.2. On Disclosure of Channel Bindings Data by Authentication
Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . 18
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
11.1. Normative References . . . . . . . . . . . . . . . . . . . . 20
11.2. Normative References for 'tls-server-end-point' . . . . . . 20
11.3. Informative References . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 22
Altman, et al. Expires October 1, 2010 [Page 3]
Internet-Draft TLS Channel Bindings March 2010
1. Conventions used in this document
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].
Altman, et al. Expires October 1, 2010 [Page 4]
Internet-Draft TLS Channel Bindings March 2010
2. Introduction
Subsequent to the publication of "On Channel Bindings" [RFC5246],
three channel binding types for Transport Layer Security (TLS) were
proposed, reviewed and added to the IANA channel binding type
registry, all in accordance with [RFC5246]. Those channel binding
types are: 'tls-unique', 'tls-server-end-point', and 'tls-unique-for-
telnet'. It has become desirable to have these channel binding types
re-registered through an RFC so as to make it easier to reference
them, and to correct them to describe actual implementations. This
document does just that. The authors of those three channel binding
types have, or have indicated that they will, transferred "ownership"
of those channel binding types to the IESG.
We also provide some advice on the applicability of these channel
binding types, as well as advice on when to use which. And we
provide an abstract API that TLS implementors should provide, by
which to obtain channel bindings data for a TLS connection.
WARNING: it turns out that the first implementor implemented and
deployed something rather different than what was described in the
IANA registration for 'tls-unique'. Subsequently it was decided that
we should adopt that form of 'tls-unique'. This means that this
document makes a backwards-incompatible change to 'tls-unique'. See
Section 8 for more details.
Altman, et al. Expires October 1, 2010 [Page 5]
Internet-Draft TLS Channel Bindings March 2010
3. The 'tls-unique' Channel Binding Type
IANA is hereby directed to update the registration of the 'tls-
unique' channel binding type to match the following. There are
material and substantial changes from the original registration, both
in the description as well as registration meta-data (such as
registration ownership).
3.1. Description
Description: The first TLS Finished message sent (note: the Finished
struct) in the most recent TLS handshake of the TLS connection being
bound to (note: TLS connection, not session, so that the channel
binding is specific to each connection regardless of whether session
resumption is used). If TLS re-negotiation takes place before the
channel binding operation, then the first TLS Finished message sent
of the latest/inner-most TLS connection is used. Note that for full
TLS handshakes the first Finished message is sent by the client,
while for abbreviated TLS handshakes (session resumption) the first
Finished message is sent by the server.
WARNING: The definition, security and interoperability considerations
of this channel binding type have changed since the original
registration. Implementors should read the document that last
updated this registration for more information.
Interoperability note:
This definition of tls-unique means that the channel's bindings
data may change over time, which in turn creates a synchronization
problem should the channel's bindings data change between the time
that the client initiates authentication with channel binding and
the time that the server begins to process the client's first
authentication message. If that happens the authentication will
fail spuriously.
This synchronization problem can be avoided by clients and servers
as follows, based on the fact that while servers may request TLS
re-negotiation, only clients may initiate it. Server applications
MUST NOT request TLS re-negotiation during phases of the
application protocol during which application layer authentication
occurs. Client applications SHOULD NOT initiate TLS re-
negotiation between the start and completion of authentication.
The rationale for making the server behavior a requirement while
the client behavior is only a recommendation is that there
typically exist TLS APIs for requesting re-negotiation on the
server side of a TLS connection, while many client TLS stacks do
Altman, et al. Expires October 1, 2010 [Page 6]
Internet-Draft TLS Channel Bindings March 2010
not provide fine-grained control over when TLS re-negotiation
occurs.
Application protocols should be designed in such a way that a
server would never need to request TLS re-negotiation immediately
before or during application-layer authentication.
3.2. Registration
o Channel binding unique prefix: tls-unique
o Channel binding type: unique
o Channel type: TLS [RFC5246]
o Published specification: <this document>
o Channel binding is secret: no
o Description: <See specification>
o Intended usage: COMMON
o Person and email address to contact for further information: Larry
Zhu (lzhu@microsoft.com), Nicolas Williams
(Nicolas.Williams@sun.com).
o Owner/Change controller name and email address: IESG.
o Expert reviewer name and contact information: IETF TLS WG
(tls@ietf.org, failing that, ietf@ietf.org)
o Note: see the published specification for advice on the
applicability of this channel binding type.
Altman, et al. Expires October 1, 2010 [Page 7]
Internet-Draft TLS Channel Bindings March 2010
4. The 'tls-server-end-point' Channel Binding Type
IANA is hereby directed to update the registration of the 'tls-
server-end-point' channel binding type to match the following. Note
that the only material changes from the original registration should
be: the "owner" (now the IESG), the contacts, the published
specfication, and a note indicating that the published specification
should be consulted for applicability advice. References were added
to the description. All other fields of the registration are copied
here for the convenience of readers.
4.1. Description
Description: The hash of the TLS server's certificate [RFC5280] as it
appears, octet for octet, in the server's Certificate message (note
that the Certificate message contains a certificate_list, the first
element of which is the server's certificate).
The hash function is to be selected as follows:
o if the certificate's signatureAlgorithm uses a single hash
function, and that hash function is either MD5 [RFC1321] or SHA-1
[RFC3174] then use SHA-256 [FIPS-180-2];
o if the certificate's signatureAlgorithm uses a single hash
function and that hash function neither MD5 nor SHA-1, then use
the hash function associated with the certificate's
signatureAlgorithm;
o if the certificate's signatureAlgorithm uses no hash functions or
multiple hash functions, then this channel binding type's channel
bindings are undefined at this time (updates to is channel binding
type may occur to address this issue if it ever arises).
The reason for using a hash of the certificate is that some
implementations need to track the channel binding of a TLS session in
kernel-mode memory, which is often at a premium.
4.2. Registration
o Channel binding unique prefix: tls-server-end-point
o Channel binding type: end-point
o Channel type: TLS [RFC5246]
o Published specification: <this document>
Altman, et al. Expires October 1, 2010 [Page 8]
Internet-Draft TLS Channel Bindings March 2010
o Channel binding is secret: no
o Description: <See specification>
o Intended usage: COMMON
o Person and email address to contact for further information: Larry
Zhu (lzhu@microsoft.com), Nicolas Williams
(Nicolas.Williams@sun.com).
o Owner/Change controller name and email address: IESG.
o Expert reviewer name and contact information: IETF TLS WG
(tls@ietf.org, failing that, ietf@ietf.org)
o Note: see the published specification for advice on the
applicability of this channel binding type.
Altman, et al. Expires October 1, 2010 [Page 9]
Internet-Draft TLS Channel Bindings March 2010
5. The 'tls-unique-for-telnet' Channel Binding Type
IANA is hereby directed to update the registration of the 'tls-
unique-for-telnet' channel binding type to match the following. Note
that the only material changes from the original registration should
be: the "owner" (now the IESG), the contacts, the published
specfication, and a note indicating that the published specification
should be consulted for applicability advice. The description is
also clarified. We also moved security considerations notes to the
security considerations section of this document. All other fields
of the registration are copied here for the convenience of readers.
5.1. Description
Description: There is a proposal for adding a "StartTLS" extension to
TELNET, and a channel binding extension for the various TELNET AUTH
mechanisms whereby each side sends the other a "checksum" (MAC) of
their view of the channel's bindings. The client uses the TLS
Finished messages (note: the Finished struct) sent by the client and
server, each concatenated in that order and in their clear text form,
of the first TLS handshake of the connection being bound to. The
server does the same but in the opposite concatenation order (server,
then client).
5.2. Registration
o Channel binding unique prefix: tls-unique-for-telnet
o Channel binding type: unique
o Channel type: TLS [RFC5246]
o Published specification: <this document>
o Channel binding is secret: no
o Description: <See specification>
o Intended usage: COMMON
o Person and email address to contact for further information: Jeff
Altman (jaltman@secure-endpoints.com), Nicolas Williams
(Nicolas.Williams@sun.com).
o Owner/Change controller name and email address: IESG.
o Expert reviewer name and contact information: IETF TLS WG
(tls@ietf.org, failing that, ietf@ietf.org)
Altman, et al. Expires October 1, 2010 [Page 10]
Internet-Draft TLS Channel Bindings March 2010
o Note: see the published specification for advice on the
applicability of this channel binding type.
Altman, et al. Expires October 1, 2010 [Page 11]
Internet-Draft TLS Channel Bindings March 2010
6. Applicability of TLS Channel Binding Types
The 'tls-unique-for-telnet' channel binding type is only applicable
to TELNET [RFC0854], and is available for all TLS connections.
The 'tls-unique' channel binding type is available for all TLS
connections, while 'tls-server-end-point' is only available when TLS
cipher suites with server certificates are used, specifically: cipher
suites that use the Certificate handshake message, which typically
involve the use of PKIX [RFC5280]. For example, 'tls-server-end-
point' is available when using TLS ciphers suites such as (this is
not an exhaustive list):
o TLS_DHE_DSS_WITH_*
o TLS_DHE_RSA_WITH_*
o TLS_DH_DSS_WITH_*
o TLS_DH_RSA_WITH_*
o TLS_ECDHE_ECDSA_WITH_*
o TLS_ECDHE_RSA_WITH_*
o TLS_ECDH_ECDSA_WITH_*
o TLS_ECDH_RSA_WITH_*
o TLS_RSA_PSK_WITH_*
o TLS_RSA_WITH_*
o TLS_SRP_SHA_DSS_WITH_*
o TLS_SRP_SHA_RSA_WITH_*
but is not available when using TLS cipher suites such as (this is
not an exhaustive list):
o TLS_DHE_PSK_WITH_*
o TLS_DH_anon_WITH_*
o TLS_ECDHE_PSK_WITH_*
o TLS_ECDH_anon_WITH_*
Altman, et al. Expires October 1, 2010 [Page 12]
Internet-Draft TLS Channel Bindings March 2010
o TLS_KRB5_WITH_*
o TLS_PSK_WITH_*
o TLS_SRP_SHA_WITH_*
Nor is 'tls-server-end-point' applicable for use with OpenPGP server
certificates [RFC5081] [RFC4880] (since these don't use the
Certificate handshake message).
Therefore 'tls-unique' is generally better than 'tls-server-end-
point'. However, 'tls-server-end-point' may be used with existing
TLS server-side proxies ("concentrators") without modification to the
proxies, whereas 'tls-unique' may require firmware or software
updates to server-side proxies. Therefore there may be cases where
'tls-server-end-point' may interoperate but where 'tls-unique' may
not.
Also, authentication mechanisms may arise which depend on channel
bindings to contribute entropy, in which case unique channel bindings
would have to always be used in preference to end-point channel
bindings. At this time there are no such mechanisms, though one such
SASL mechanism has been proposed. Whether such mechanisms should be
allowed is out of scope for this document.
In other words, for many applications there may be two potentially
applicable TLS channel binding types. Channel binding is all or
nothing for the GSS-API [RFC2743], and likely other frameworks.
Therefore agreement on the use of channel binding, and a particular
channel binding type is necessary. Such agreement can be obtained a
priori, by convention, or negotiated.
The specifics of whether and how to negotiate channel binding types
are beyond the scope of this document. However, it is RECOMMENDED
that application protocols making use of TLS channel bindings, use
'tls-unique' exclusively, except, perhaps, where server-side proxies
are common in deployments of an application protocol. In the latter
case an application protocol MAY specify that 'tls-server-end-point'
channel bindings must be used when available, with 'tls-unique' being
used when 'tls-server-end-point' channel bindings are not available.
Alternatively, the application may negotiate which channel binding
type to use, or may make the choice of channel binding type
configurable.
Specifically, application protocol specifications MUST indicate at
least one mandatory to implement channel binding type, MAY specify a
negotiation protocol, MAY allow for out-of-band negotiation or
configuration, and SHOULD have a preference for 'tls-unique' over
Altman, et al. Expires October 1, 2010 [Page 13]
Internet-Draft TLS Channel Bindings March 2010
'tls-server-end-point'.
Altman, et al. Expires October 1, 2010 [Page 14]
Internet-Draft TLS Channel Bindings March 2010
7. Required Application Programming Interfaces
TLS implementations supporting the use of 'tls-unique' and/or 'tls-
unique-for-telnet' channel binding types, MUST provide application
programming interfaces by which applications (clients and servers
both) may obtain the channel bindings for a TLS connection. Such
interfaces may be expressed in terms of extracting the channel
bindings data for a given connection and channel binding type.
Alternatively the implementor may provide interfaces by which to
obtain the initial client Finished message, the initial server
Finished message and/or the server certificate (in a form that
matches the description of the 'tls-server-end-point' channel binding
type). In the latter case the application has to have knowledge of
the channel binding type descriptions from this document. This
document takes no position on which form these application
programming interfaces must take.
TLS implementations supporting TLS re-negotiation SHOULD provide APIs
that allow for application control over when re-negotiation can take
place. For example, a TLS client implementation may provide a
"callback" interface to indicate that the server requested re-
negotiation, but may not start re-negotiation until the application
calls a function to indicate that now is a good time to re-negotiate.
Altman, et al. Expires October 1, 2010 [Page 15]
Internet-Draft TLS Channel Bindings March 2010
8. Description of backwards-incompatible changes made herein to 'tls-
unique'
The original description of 'tls-unique' read as follows:
|OLD| Description: The client's TLS Finished message (note: the
|OLD| Finished struct) from the first handshake of the connection
|OLD| (note: connection, not session, so that the channel binding
|OLD| is specific to each connection regardless of whether session
|OLD| resumption is used).
Original 'tls-unique' description
In other words: the client's Finished message from the first handhske
of a connection, regardless of whether that handshake was a full or
abbreviated handshake, and regardless of how many subsequent
handshakes (re-negotiations) might have followed.
As explained in Section 2 this is no longer the description of 'tls-
unique', and the new description is not backwards compatible with the
original except in the case of TLS connections where: a) only one
handshake has taken place before application-layer authentication,
and b) that one handshake was a full handshake.
This change has a number of implications:
o Backwards-incompatibility. It is possible that some
implementations of the original 'tls-unique' channel binding type
may have been deployed. We know of at least one TLS
implementation that exports 'tls-unique' channel bindings with the
original semantics, but we know of no deployed application using
the same. Implementations of the original and new 'tls-unique'
channel binding type will only interoperate when: a) full TLS
handshakes are used, b) TLS re-negotiation is not used.
o Security considerations -- see Section 10.
o Interoperability considerations. As described in Section 3 the
new definition of the 'tls-unique' channel binding type has an
interoperability problem that may result in spurious
authentication failures unless the application implements one or
both of the the techniques described in that section.
Altman, et al. Expires October 1, 2010 [Page 16]
Internet-Draft TLS Channel Bindings March 2010
9. IANA Considerations
The IANA is hereby directed to update three existing channel binding
type registrations. See the rest of this document.
Altman, et al. Expires October 1, 2010 [Page 17]
Internet-Draft TLS Channel Bindings March 2010
10. Security Considerations
The Security Considerations sections of [RFC5056], [RFC5246] and
[RFC5746] apply to this document.
The TLS Finished messages (see section 7.4.9 of [RFC5246]) are known
to both endpoints of a TLS connection, and are cryptographycally
bound to it. For implementations of TLS that correctly handle re-
negotiation [RFC5746] each handshake on a TLS connection is bound to
the preceding handshake, if any. Therefore the TLS Finished messages
can be safely used as a channel binding provided that the
authentication mechanism doing the channel binding conforms to the
requirements in [RFC5056]. Applications utilizing 'tls-unique'
channel binding with TLS implementations without support for secure
re-negotiation [RFC5746] MUST ensure that that ChangeCipherSpec has
been used in any and all re-negotiations prior to application-layer
authentication, and MUST discard any knowledge learned from the
server prior to the completion of application-layer authentication.
The server certificate, when present, is also cryptographically bound
to the TLS connection through its use in key transport and/or
authentication of the server (either by dint of its use in key
transport, by its use in signing key agreement, or by its use in key
agreement). Therefore the server certificate is suitable as an end-
point channel binding as described in [RFC5056].
10.1. Cryptographic Algorithm Agility
The 'tls-unique' and 'tls-unique-for-telnet' channel binding types do
not add any use of cryptography beyond that used by TLS itself.
Therefore these two channel binding types add no considerations with
respect to cryptographic algorithm agility.
The 'tls-server-end-point' channel binding type consist of a hash of
a server certificate. The reason for this is to produce manageably
small channel binding data, as some implementations will be using
kernel-mode memory (which is typically scarce) to store these. This
use of a hash algorithm is above and beyond TLS's use of
cryptography, therefore the 'tls-server-end-point' channel binding
type has a security consideration with respect to hash algorithm
agility. The algorithm to be used, however, is derived from the
server certificate's signature algorithm as described in Section 4.1;
to recap: use SHA-256 if the certificate signature algorithm uses MD5
or SHA-1, else use whatever hash function the certificate uses
(unless the signature algorithm uses no hash functions or more than
one hash function, in which case 'tls-server-end-point' is
undefined). This construction automatically makes 'tls-server-end-
point' hash algorithm agile, with a dependency on PKIX and TLS for
Altman, et al. Expires October 1, 2010 [Page 18]
Internet-Draft TLS Channel Bindings March 2010
hash agility.
Current proposals for randomized signatures algorithms
[I-D.irtf-cfrg-rhash] [NIST-SP.800-106.2009] use hash functions in
their construction -- a single hash function in each algorithm.
Therefore the 'tls-server-end-point' channel binding type should be
available even in cases where new signatures algorithms are used that
are based on current randomized hashing proposals (but we cannot
guarantee this, of course).
10.2. On Disclosure of Channel Bindings Data by Authentication
Mechanisms
When these channel binding types were first considered, one issue
that some commenters were concerned about was the possible impact on
the security of the TLS channel, of disclosure of the channel
bindings data by authentication mechanisms. This can happen, for
example, when an authentication mechanism transports the channel
bindings data, with no confidentiality protection, over other
transports (for example, in communicating with a trusted third
party), or when the TLS channel provides no confidentiality
protection and the authentication mechanism does not protect the
confidentiality of the channel bindings data. This section considers
that concern.
When the TLS connection uses a cipher suite that does not provide
confidentiality protection, the TLS Finished messages will be visible
to eavesdroppers, regardless of what the authentication mechanism
does. The same is true of the server certificate which, in any case,
is generally visible to eavesdroppers. Therefore we must consider
our choices of TLS channel bindings here to be safe to disclose by
definition -- if that were not the case then TLS with cipher suites
that don't provide confidentiality protection would be unsafe.
Furthermore, the TLS Finished message construction depends on the
security of the TLS PRF, which in turn needs to be resistant to key
recovery attacks, and we think that it is, as it is based on HMAC,
and the master secret is, well, secret (and the result of key
exchange).
Note too that in the case of an attempted active man-in-the-middle
attack, the attacker will already possess knowledge of the TLS
finished messages for both inbound and outbound TLS channels (which
will differ, given that the attacker cannot force them to be the
same). No additional information is obtained by the attacker from
the authentication mechanism's disclosure of channel bindings data --
the attacker already has it, even when cipher suites providing
confidentiality protection are provided.
Altman, et al. Expires October 1, 2010 [Page 19]
Internet-Draft TLS Channel Bindings March 2010
None of the channel binding types defined herein produce channel
bindings data that must be kept secret. Moreover, none of the
channel binding types defined herein can be expected to be private
(known only to the end-points of the channel), except that the unique
TLS channel binding types can be expected to be private when a cipher
suite that provides confidentiality protection is used to protect the
Finished message exchanges and the application data records
containing application-layer authentication messages.
Altman, et al. Expires October 1, 2010 [Page 20]
Internet-Draft TLS Channel Bindings March 2010
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5056] Williams, N., "On the Use of Channel Bindings to Secure
Channels", RFC 5056, November 2007.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5746] Rescorla, E., Ray, M., Dispensa, S., and N. Oskov,
"Transport Layer Security (TLS) Renegotiation Indication
Extension", RFC 5746, February 2010.
11.2. Normative References for 'tls-server-end-point'
[FIPS-180-2]
United States of America, National Institute of Standards
and Technology, "Secure Hash Standard (Federal Information
Processing Standard (FIPS) 180-2".
11.3. Informative References
[I-D.irtf-cfrg-rhash]
Halevi, S. and H. Krawczyk, "Strengthening Digital
Signatures via Randomized Hashing",
draft-irtf-cfrg-rhash-01 (work in progress), October 2007.
[NIST-SP.800-106.2009]
National Institute of Standards and Technology, "NIST
Special Publication 800-106: Randomized Hashing for
Digital Signatures", February 2009.
[RFC0854] Postel, J. and J. Reynolds, "Telnet Protocol
Specification", STD 8, RFC 854, May 1983.
[RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
April 1992.
[RFC2743] Linn, J., "Generic Security Service Application Program
Interface Version 2, Update 1", RFC 2743, January 2000.
[RFC3174] Eastlake, D. and P. Jones, "US Secure Hash Algorithm 1
(SHA1)", RFC 3174, September 2001.
Altman, et al. Expires October 1, 2010 [Page 21]
Internet-Draft TLS Channel Bindings March 2010
[RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R.
Thayer, "OpenPGP Message Format", RFC 4880, November 2007.
[RFC5081] Mavrogiannopoulos, N., "Using OpenPGP Keys for Transport
Layer Security (TLS) Authentication", RFC 5081,
November 2007.
[RFC5280] 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.
Altman, et al. Expires October 1, 2010 [Page 22]
Internet-Draft TLS Channel Bindings March 2010
Authors' Addresses
Jeff Altman
Secure Endpoints
255 W 94TH ST PHB
New York, NY 10025
US
Email: jaltman@secure-endpoints.com
Nicolas Williams
Oracle
5300 Riata Trace Ct
Austin, TX 78727
US
Email: Nicolas.Williams@oracle.com
Larry Zhu
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
US
Email: lzhu@microsoft.com
Altman, et al. Expires October 1, 2010 [Page 23]
