Archive for the 'Cryptography' Category

October 17, 2014
JOSE -35 and JWT -29 drafts addressing AppsDir review comments

IETF logoI’ve posted updated JOSE and JWT drafts that address the Applications Area Directorate review comments. Thanks to Ray Polk and Carsten Bormann for their useful reviews. No breaking changes were made.

The specifications are available at:

HTML formatted versions are available at:

October 14, 2014
JOSE -34 and JWT -28 drafts addressing IESG review comments

IETF logoUpdated JOSE and JWT specifications have been published that address the IESG review comments received. The one set of normative changes was to change the implementation requirements for RSAES-PKCS1-V1_5 from Required to Recommended- and for RSA-OAEP from Optional to Recommended+. Thanks to Richard Barnes, Alissa Cooper, Stephen Farrell, Brian Haberman, Ted Lemon, Barry Leiba, and Pete Resnick for their IESG review comments, plus thanks to Scott Brim and Russ Housley for additional Gen-ART review comments, and thanks to the working group members who helped respond to them. Many valuable clarifications resulted from your thorough reviews.

The specifications are available at:

HTML formatted versions are available at:

September 25, 2014
JOSE -33 and JWT -27 drafts addressing Stephen Kent’s JWK comments

IETF logoUpdated JOSE and JWT drafts have been published that address JSON Web Key (JWK) secdir review comments by Stephen Kent that were inadvertently not addressed in the previous versions. Most of the changes were to the JWK draft. A few changes also had to be made across the other drafts to keep them in sync. I also added acknowledgements to several additional contributors. No breaking changes were made.

The specifications are available at:

Differences since the previous drafts can be viewed at:

HTML formatted versions are available at:

September 23, 2014
JOSE -32 and JWT -26 drafts addressing IETF Last Call comments

IETF logoNew versions of the JSON Object Signing and Encryption (JOSE) and JSON Web Token (JWT) specifications have been published incorporating feedback received in IETF Last Call comments. Thanks to Russ Housley and Roni Even for their Gen-ART reviews, to Tero Kivinen, Scott Kelly, Stephen Kent, Charlie Kaufman, and Warren Kumari for their secdir reviews, to Tom Yu for his individual review, and to James Manger and Chuck Mortimore who provided feedback based on deployment experiences, as well as to the many JOSE and OAuth working group members who pitched in to discuss resolutions. Many clarifications resulted. No breaking changes were made.

The specifications are available at:

HTML formatted versions are available at:

August 20, 2014
Microsoft JWT and OpenID Connect RP libraries updated

This morning Microsoft released updated versions of its JSON Web Token (JWT) library and its OpenID Connect RP library as part of today’s Katana project release. See the Microsoft.Owin.Security.Jwt and Microsoft.Owin.Security.OpenIdConnect packages in the Katana project’s package list. These are .NET 4.5 code under an Apache 2.0 license.

For more background on Katana, you can see this post on Katana design principles and this post on using claims in Web applications. For more on the JWT code, see this post on the previous JWT handler release.

Thanks to Brian Campbell of Ping Identity for performing OpenID Connect interop testing with us prior to the release.

August 14, 2014
The Increasing Importance of Proof-of-Possession to the Web

W3C  logoMy submission to the W3C Workshop on Authentication, Hardware Tokens and Beyond was accepted for presentation. I’ll be discussing The Increasing Importance of Proof-of-Possession to the Web. The abstract of my position paper is:

A number of different initiatives and organizations are now defining new ways to use proof-of-possession in several kinds of Web protocols. These range from cookies that can’t be stolen and reused, identity assertions only usable by a particular party, password-less login, to proof of eligibility to participate. While each of these developments is important in isolation, the pattern of all of them concurrently emerging now demonstrates the increasing importance of proof-of-possession to the Web.

It should be a quick and hopefully worthwhile read. I’m looking forward to discussing it with many of you at the workshop!

July 23, 2014
OAuth Assertions specs describing Privacy Considerations

OAuth logoBrian Campbell updated the OAuth Assertions specifications to add Privacy Considerations sections, responding to area director feedback. Thanks, Brian!

The specifications are available at:

HTML formatted versions are also available at:

July 23, 2014
JWK Thumbprint spec incorporating feedback from IETF 90

IETF logoI’ve updated the JSON Web Key (JWK) Thumbprint specification to incorporate the JOSE working group feedback on the -00 draft from IETF 90. The two changes were:

  • Said that the result is undefined if characters requiring escaping are needed in the hash input.
  • Added instructions for representing integer numeric values in the hash input.

If a canonical JSON representation standard is ever adopted, this specification could be revised to use it, resulting in unambiguous definitions for those values (which are unlikely to ever occur in JWKs) as well. (Defining a complete canonical JSON representation is very much out of scope for this work!)

The specification is available at:

An HTML formatted version is also available at:

July 4, 2014
JOSE -31 and JWT -25 drafts addressing additional AD comments

IETF logoIn preparation for IETF 90 in Toronto, I’ve published yet another round of small deltas to the JOSE and JWT specifications motivated by additional comments from our area director, Kathleen Moriarty. These drafts add some references to Security Considerations sections, adds a Privacy Considerations section to JWT, and clarifies wording in a few places. Once again, no normative changes were made.

The specifications are available at:

HTML formatted versions are available at:

July 1, 2014
JOSE -30 and JWT -24 drafts incorporating AD feedback on fifth spec of five

IETF logoJOSE -30 and JWT -24 drafts have been posted incorporating improvements resulting from Kathleen Moriarty’s JWE review. At this point, actions requested in her reviews of the JWS, JWE, JWK, JWA, and JWT specifications have all been incorporated. All changes in this release were strictly editorial in nature.

The specifications are available at:

HTML formatted versions are available at:

June 20, 2014
JOSE -29 and JWT -23 drafts coalescing duplicative terminology definitions

IETF logoSurprise! For the first time ever, I’ve released two sets of JOSE and JWT drafts in one day! I wanted to separate the changes addressing recent AD comments from this set of changes that reduces duplication in the drafts.

These drafts replaced the terms JWS Header, JWE Header, and JWT Header with a single JOSE Header term defined in the JWS specification. This also enabled a single Header Parameter definition to be used and reduced other areas of duplication between the specifications. No normative changes were made.

The specifications are available at:

HTML formatted versions are available at:

June 20, 2014
JOSE -28 and JWT -22 drafts incorporating additional AD feedback

IETF logoUpdated JOSE and JWT drafts have been released that incorporate additional wording improvements in places suggested by Kathleen Moriarty. Most of the changes were rewording and reorganization of the Security Considerations sections. An explanation of when applications typically would and would not use the typ and cty header parameters was added. The one normative change was to specify the use of PKCS #7 padding with AES CBC, rather than PKCS #5 – a correction pointed out by Shaun Cooley. (PKCS #7 is a superset of PKCS #5, and is appropriate for the 16 octet blocks used by AES CBC.) No breaking changes were made.

The specifications are available at:

HTML formatted versions are available at:

June 10, 2014
JOSE -27 and JWT -21 drafts incorporating area director feedback

IETF logoThe -27 drafts of the JOSE specs (JWS, JWE, JWK, & JWA) and the -21 draft of the JWT spec have been posted that incorporate feedback received from our security area director, Kathleen Moriarty. The one normative change was to add certificate thumbprint parameters using SHA-256 as the hash function. There were no breaking changes. A number of additional security considerations were added across the drafts. An example JWK was added early in the JWK draft (paralleling the early examples in the JWS, JWE, and JWT drafts). Several algorithm cross-reference entries were updated in the JWA draft. A number of other editorial improvements were also applied.

The specifications are available at:

HTML formatted versions are available at:

Thanks for the detailed feedback, Kathleen.

May 14, 2014
JWT and JOSE have won a Special European Identity Award

IETF logoToday the JSON Web Token (JWT) and JSON Object Signing and Encryption (JOSE) specifications were granted a Special European Identity Award for Best Innovation for Security in the API Economy. I was honored to accept the award, along with Nat Sakimura and John Bradley, on behalf of the contributors to and implementers of these specifications at the European Identity and Cloud Conference.

It’s great to see this recognition for the impact that these specs are having by making it easy to use simple JSON-based security tokens and other Web-friendly cryptographically protected data structures. Special thanks are due to all of you have built and deployed implementations and provided feedback on the specs throughout their development; they significantly benefitted from your active involvement!

These specifications are:

The authors are:

Dirk Balfanz, Yaron Goland, John Panzer, and Eric Rescorla also deserve thanks for their significant contributions to creating these specifications.

May 8, 2014
Publication requested for JSON Web Token (JWT), OAuth Assertions, and JOSE specifications

IETF logoToday, the OAuth Working Group requested publication of four specifications as proposed standards:

This follows on the JOSE Working Group likewise requesting publication of the JSON Object Signing and Encryption specifications last month:

This means that the working groups have sent the specifications to the IESG for review, which is the next step towards them becoming IETF Standards – RFCs.

April 30, 2014
JOSE -26 and JWT -20 drafts addressing editorial issues

IETF logoThe JOSE -26 and JWT -20 drafts address a few editorial issues recently identified by reviewers, hopefully further clarifying these aspects of the specifications. No normative changes were made.

See the Document History entries for details on the specific changes made.

The specifications are available at:

HTML formatted versions are also available at:

April 10, 2014
JSON Web Key (JWK) Thumbprint Specification

IETF logoI created a new simple spec that defines a way to create a thumbprint of an arbitrary key, based upon its JWK representation. The abstract of the spec is:

This specification defines a means of computing a thumbprint value (a.k.a. digest) of JSON Web Key (JWK) objects analogous to the x5t (X.509 Certificate SHA-1 Thumbprint) value defined for X.509 certificate objects. This specification also registers the new JSON Web Signature (JWS) and JSON Web Encryption (JWE) Header Parameters and the new JSON Web Key (JWK) member name jkt (JWK SHA-256 Thumbprint) for holding these values.

The desire for this came up in an OpenID Connect context, but it’s of general applicability, so I decided to submit the spec to the JOSE working group. Thanks to James Manger, John Bradley, and Nat Sakimura for the discussions that led up to this spec.

The specification is available at:

An HTML formatted version is also available at:

April 1, 2014
Proof-Of-Possession Semantics for JSON Web Tokens (JWTs)

OAuth logoI’ve written a concise Internet-Draft on proof-of-possession for JWTs with John Bradley and Hannes Tschofenig. Quoting from the abstract:

This specification defines how to express a declaration in a JSON Web Token (JWT) that the presenter of the JWT possesses a particular key and that the recipient can cryptographically confirm proof-of-possession of the key by the presenter. This property is also sometimes described as the presenter being a holder-of-key.

This specification intentionally does not specify the means of communicating the proof-of-possession JWT, nor the messages used to exercise the proof key, as these are necessarily application-specific. Rather, this specification defines a proof-of-possession JWT data structure to be used by other specifications that do define those things.

The specification is available at:

An HTML formatted version is available at:

March 31, 2014
JOSE -25 drafts fixing typos and updating references

IETF logoJOSE -25 drafts have been released that fix a few typos and update the WebCrypto reference to refer to the W3C Last Call draft.

The specifications are available at:

HTML formatted versions are also available at:

Thanks to Antonio Sanso for bringing the typos to our attention.

March 20, 2014
Growing list of OpenID Connect libraries available

OpenID logoAs described in today’s openid.net post, a growing list of OpenID Connect and JWT/JOSE libraries are available. Check them out at http://openid.net/developers/libraries/.

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