draft-ietf-tls-cached-info-01.txt   draft-ietf-tls-cached-info-02.txt 
INTERNET-DRAFT S. Santesson (3xA Security) INTERNET-DRAFT S. Santesson (3xA Security)
Intended Status: Proposed Standard Q. Dang (NIST) Intended Status: Proposed Standard
Expires: March 19, 2010 September 15, 2009
Transport Layer Security (TLS) Cached Information Extension Transport Layer Security (TLS) Cached Information Extension
<draft-ietf-tls-cached-info-01.txt> <draft-ietf-tls-cached-info-02.txt>
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
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Copyright Notice
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Abstract Abstract
This document defines a Transport Layer Security (TLS) extension for This document defines a Transport Layer Security (TLS) extension for
cached information. This extension allows the TLS client to inform a cached information. This extension allows the TLS client to inform a
server of cached information from previous TLS sessions, allowing the server of cached information from previous TLS sessions, allowing the
server to omit sending cached static information to the client during server to omit sending cached static information to the client during
the TLS handshake protocol exchange. the TLS handshake protocol exchange.
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Cached Information Extension . . . . . . . . . . . . . . . . . . 3
4 Message flow . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5 Security Considerations . . . . . . . . . . . . . . . . . . . . 4
6 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
7 Normative References . . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1 Introduction 1 Introduction
TLS handshakes often include fairly static information such as server TLS handshakes often include fairly static information such as server
certificate and a list of trusted Certification Authorities (CAs). certificate and a list of trusted Certification Authorities (CAs).
Static information such as a server certificate can be of Static information such as a server certificate can be of
considerable size. This is the case in particular if the server considerable size. This is the case in particular if the server
certificate is bundled with a complete certificate path, including certificate is bundled with a complete certificate path, including
all intermediary certificates up to the trust anchor public key. all intermediary certificates up to the trust anchor public key.
Significant benefits can be achieved in low bandwidth and high Significant benefits can be achieved in low bandwidth and high
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caching of information objects by including an extension of type caching of information objects by including an extension of type
"cached_information" with an empty extension_data field in their "cached_information" with an empty extension_data field in their
(extended) server hello. (extended) server hello.
Following a successful exchange of "cached_information" extensions, Following a successful exchange of "cached_information" extensions,
the server may replace data objects identified through the client the server may replace data objects identified through the client
extension with any of the CachedInformationHash values received from extension with any of the CachedInformationHash values received from
the client, which matches the replaced object. the client, which matches the replaced object.
The handshake protocol will proceed using the cached data as if it The handshake protocol will proceed using the cached data as if it
was provided in the handshake protocol. The finished message will was provided in the handshake protocol. The Finished message will
however be calculated over the actual data exchanged in the handshake however be calculated over the actual data exchanged in the handshake
protocol. That is, the finished message will be calculated over the protocol. That is, the Finished message will be calculated over the
hash values of cached information objects and not over the cached hash values of cached information objects and not over the cached
objects that were omitted from transmission. objects that were omitted from transmission.
5 Security Considerations 5 Security Considerations
Hash algorithms used in this specification are required to have Hash algorithms used in this specification are required to have
reasonable random properties in order to provide reasonably unique reasonable random properties in order to provide reasonably unique
identifiers. Failure of a provided hash to correctly and uniquely identifiers. Failure of a provided hash to correctly and uniquely
identify the correct set of hashed parameters may at most lead to a identify the correct set of hashed parameters may at most lead to a
failed TLS handshake followed by a new attempt without the cached failed TLS handshake followed by a new attempt without the cached
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trusted_cas(2). TLS CachedInformationType values in the inclusive trusted_cas(2). TLS CachedInformationType values in the inclusive
range 0-63 (decimal) are assigned via RFC 5226 [RFC5226] Standards range 0-63 (decimal) are assigned via RFC 5226 [RFC5226] Standards
Action. Values from the inclusive range 64-223 (decimal) are Action. Values from the inclusive range 64-223 (decimal) are
assigned via RFC 5226 Specification Required. Values from the assigned via RFC 5226 Specification Required. Values from the
inclusive range 224-255 (decimal) are reserved for RFC 5226 inclusive range 224-255 (decimal) are reserved for RFC 5226
Private Use. Private Use.
7 Normative References 7 Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
[RFC5226] T. Narten, H. Alvestrand, "Guidelines for Writing an [RFC5226] T. Narten, H. Alvestrand, "Guidelines for Writing an IANA
IANA Considerations Section in RFCs", RFC 5226,
[RFC5246] T. Dierks, E. Rescorla, "The Transport Layer Security [RFC5246] T. Dierks, E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008 (TLS) Protocol Version 1.2", RFC 5246, August 2008
[RFC4366] S. Blake-Wilson, M. Nystrom, D. Hopwood, J. Mikkelsen, [RFC4366] S. Blake-Wilson, M. Nystrom, D. Hopwood, J. Mikkelsen, T.
T. Wright, "Transport Layer Security (TLS) Extensions", Wright, "Transport Layer Security (TLS) Extensions", RFC
NOTE: RFC 4366 will be updated by RFC4366bis, currently in IESG
process.
Authors' Addresses Authors' Addresses
Stefan Santesson Stefan Santesson
3xA Security AB 3xA Security AB
Bjornstorp 744 Bjornstorp 744
247 98 Genarp 247 98 Genarp
Sweden Sweden
EMail: sts@aaa-sec.com EMail: sts@aaa-sec.com
Quynh Dang
NIST
100 Bureau Drive, Stop 8930
Gaithersburg, MD 20899-8930
USA
Email: quynh.dang@nist.gov
Full Copyright Statement
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/licenseinfo).
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
All IETF Documents and the information contained therein are provided
on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
WARRANTY THAT THE USE OF THE INFORMATION THEREIN WILL NOT INFRINGE
ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE.
Expires December 2009
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