Draft N. Sakimura NRI J. Bradley Protiviti M. Jones Microsoft B. de Medeiros Google C. Mortimore Salesforce E. Jay MGI1 July 6, 2011 OpenID Connect Session Management 1.0 - draft 01 Abstract This document describes how to manage sessions for OpenID Connect. Sakimura, et al. [Page 1] Abbreviated-Title July 2011 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 RFC 2119 [RFC2119]. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Session Management . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Creating Sessions . . . . . . . . . . . . . . . . . . . . 5 3.1.1. ID Token . . . . . . . . . . . . . . . . . . . . . . . 5 3.1.2. Authorization Request . . . . . . . . . . . . . . . . 6 3.1.3. Token Endpoint . . . . . . . . . . . . . . . . . . . . 7 3.1.4. Implicit (User-Agent) Flow . . . . . . . . . . . . . . 7 3.1.5. Authorization Code (Web Server) Flow . . . . . . . . . 9 3.1.6. 4th Party Native Applications . . . . . . . . . . . . 12 3.2. Session Management Endpoints . . . . . . . . . . . . . . . 14 3.2.1. Refresh Session . . . . . . . . . . . . . . . . . . . 15 3.2.2. Check Session . . . . . . . . . . . . . . . . . . . . 16 3.2.3. End Session . . . . . . . . . . . . . . . . . . . . . 17 3.3. Session Synchronization . . . . . . . . . . . . . . . . . 18 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 5. Security Considerations . . . . . . . . . . . . . . . . . . . 20 6. Normative References . . . . . . . . . . . . . . . . . . . . . 21 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 22 Appendix B. Document History . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24 Sakimura, et al. [Page 2] Abbreviated-Title July 2011 1. Introduction Sessions are used to keep track of information and interactions for users across multiple pages. This creates a sense of continuity, customization, and a more pleasant experience for the users. Visitors to an OpenID relying party site accessing protected resources will be asked for authentication and authorization. Upon user authorization, the user will be granted access to the requested resources. The site may perform other background tasks for the user using the same authenticated session. This allows the user to have a simplified experience without being asked for authorization each time and may even allow the user to go off-line while the tasks are being performed. This specification describes how OpenID Connect sessions can be created, used, and terminated. Sakimura, et al. [Page 3] Abbreviated-Title July 2011 2. Terminology In addition to the terminology defined in the OpenID Connect Core 1.0 [OpenID.Core] specification, the following terms are defined: Client An application obtaining authorization and making protected resource requests. End-user A human resource owner. Client Identifier A unique identifier that the client uses to identify itself to the OP. Identifier An Identifier is either an "http" or "https" URI, (commonly referred to as a "URL" within this document), or an account URI. This document defines various kinds of Identifiers, designed for use in different contexts. ID Token An opaque token that contains claims about an authenticated user. ID Token A JWS signed claim that attest to the identity of the user, intended audience, and the issuer of the claim. The signed claim uses compact serialization. Sakimura, et al. [Page 4] Abbreviated-Title July 2011 3. Session Management The OpenID Connect Core supports life-cycle session management and synchronization for third parties that support authentication with the authorization server. In addition, session management for fourth parties such as desktop, native or mobile applications that utilizes authorization server credentials at fourth party web sites are also supported. 3.1. Creating Sessions To create a session, the client sends an authorization request to the authorization server with "id_token" as one of the "response_type" values. If the "response_type" includes the value "code", then an ID token (Section 3.1.1) is returned in the response of the Token Endpoint when the Access Token is retrieved. If the "response_type" includes the value "token", then an ID token is returned as a fragment parameter in the "redirect_uri" specified in the request. In either case, an ID Token will also be returned along with the access token when submitting a refresh token to the token access endpoint if the initial authorization request included "id_token" in the "response_type" parameter. The ID Token serves as a key to an authenticated user session and contains claims for the user. 3.1.1. ID Token This specification defines ID Token as a JWS signed claim that minimally attests the following claims: issuer REQUIRED. The unique identifier of the issuer of the claims client_id REQUIRED. The unique identifier of the client. user_id REQUIRED. A locally unique and never reassigned identifier for the user, which is intended to be consumed by the Client. e.g. "24400320" or "AItOawmwtWwcT0k51BayewNvutrJUqsvl6qs7A4". It MUST NOT exceed 255 ASCII characters in length. Sakimura, et al. [Page 5] Abbreviated-Title July 2011 audience REQUIRED. The JWT [JWT] aud (audience) claim. exp REQUIRED. The JWT [JWT] exp (expiration time) claim. pape OPTIONAL. (TBD) If we want this token to be short, we probably want to define a shorter equivalent of PAPE. nonce OPTIONAL. If the authorization request includes a nonce request value, then this value is REQUIRED and its value is set to the same value as the request value. The ID Token MAY contain other claims. The ID Token can be used to access session information from an authenticated session or to pass a session to other applications. The ID Token MAY be redefined by other OpenID session related specifications. 3.1.2. Authorization Request Section 4.1.1 and 4.2.1 of OAuth 2.0 [OAuth.2.0] defines OAuth Authorization Request parameters. In this specification, the values to the parameters are defined as follows. response_type A space delimited, case sensitive list of string values (Pending OAuth 2.0 changes). This specification extends the OpenID core "response_type" values to include "id_token" . The value MUST include "id_token" for requesting an ID Token from a session. In addition, this specification defines the following extension parameters. nonce OPTIONAL. A random, unique string. The nonce value is returned in the ID token. id_token_audience OPTIONAL. The identifier of the target audience for an ID token. Following is a non-normative example when they are sent in the query parameters serialization: GET /authorize?scope=openid&response_type=token%20id_token &client_id=s6BhdRkqt3 &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb Host: server.example.com Sakimura, et al. [Page 6] Abbreviated-Title July 2011 3.1.3. Token Endpoint The Token Endpoint MUST return an ID Token if "id_token" is included in the "response_type" parameter of the authorization request. 3.1.3.1. Access Token Response After receiving and verifying a valid and authorized Access Token Request from the client, the Authorization Server returns a Positive Assertion that includes an Access Token. The parameters in the successful response are defined in Section 4.2.2 of OAuth 2.0 [OAuth.2.0] . In addition, this specification defines the following additional return parameters: id_token REQUIRED if it was requested in the authorization request. It may be a JWS [JWS] of the ID token (Section 3.1.1) described below. Following is a non-normative example: { "access_token": "SlAV32hkKG", "token_type": "JWT", "refresh_token": "8xLOxBtZp8", "expires_in": 3600, "id_token":"jwtheader.jwtpayload.jwtcrypto" } As in the OAuth 2.0 [OAuth.2.0], Clients SHOULD ignore unrecognized response parameters. 3.1.4. Implicit (User-Agent) Flow User-agents can use the OAuth implicit grant flow by including "token" and "id_token" in the "response_type" of the authorization request to get an ID Token. 1. The user-agent makes an authorization request to the authorization endpoint. 2. The authorization server authenticates the user 3. The authorization server returns an access and ID token. 4. The user-agent and client servlet can then use the session management endpoints by presenting the ID token to the endpoints. Sakimura, et al. [Page 7] Abbreviated-Title July 2011 +----------------------------------+ +----------+ | | | | | +----------------------+ | | | | | Authorization | | | | | | server | | |user-agent| | +----------------------+ | | | | | +---------------+ | | | |>----(1)-------------|------|-->| Authorization | | | | |<----(3)-------------|------|--<| Endpoint (2) | | | +----------+ | | +---------------+ | | ^ +----------|------|--<| Check_Session | | | | | +--------|------|-->| EndPoint | | | | | | | | +---------------+ | | v | | | +----------------------+ | +----------+ (4)| | | | | | | | | | |client |<---------+ | | +----------------------+ | |servlet |>-----------+ | | Profile API/ | | | | | | UserInfo Endpoint| | | | | | | | | |>--------------------|----->| | | | |<--------------------|-----<| | | | | | | | | | | | | | | +----------+ | +----------------------+ | | | | | +----------------------------------+ +-----------------------------+ | | | Authorization | | Server | +-------------+ | | | | | +--------------------+ | | User-Agent | | | Refresh Session | | | | (4) | | Endpoint | | | |>-------------|---->| | | | |<-------------|----<| | | | | | | | | | | | +--------------------+ | | | (4) | | End Session | | | |>-------------|---->| Endpoint | | | |<-------------|----<| | | | | | | | | | | | +--------------------+ | +-------------+ +-----------------------------+ Sakimura, et al. [Page 8] Abbreviated-Title July 2011 3.1.4.1. Implicit Flow Request The authorization request parameter values are constrained as follows. response_type A space delimited, case sensitive list of string values (Pending OAuth 2.0 changes). The value MUST include "token" and "id_token" and to request an access and ID Token from the session. Following is a non-normative example of a request using query parameters serialization: GET /authorize?scope=openid&response_type=token%20id_token &client_id=s6BhdRkqt3 &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb Host: server.example.com 3.1.4.2. Implicit Flow Response When the "response_type" in the request includes "token", the Authorization Response MUST return the parameters defined in section 4.2.2 of OAuth 2.0 [OAuth.2.0]. In addition, when "response_type" includes "id_token", an ID Token MUST be returned in the response. Following is a non-normative example of a response: HTTP/1.1 302 Found Location: https://client.example.com/cb?token=i1WsRn1uB1&id_token=jwt_header.jwt_payload.jwt_crypto 3.1.5. Authorization Code (Web Server) Flow Web server clients can use the OAuth authorization code flow by including "code" and "id_token" in the "response_type" parameter of the authorization request to obtain an ID token. The ID Token is returned along with the access token after the client submits the authorization code to the access token endpoint. 1. The user-agent makes an authorization request to the authorization endpoint. 2. The authorization server authenticates the user 3. The authorization server returns an authorization code. 4. The client sends authorization code to the token access endpoint. Sakimura, et al. [Page 9] Abbreviated-Title July 2011 5. The authorization server verifies the authorization token and returns an access and ID token 6. The user-agent and client servlet can then use the session management endpoints by presenting the ID token to the endpoints. +----------------------------------+ +----------+ | | | | | +----------------------+ | | | | | Authorization | | | | | | server | | |user-agent| | +----------------------+ | | | | | +---------------+ | | | |>-----(1)------------|------|-->| Authorization | | | | |<-----(3)------------|------|--<| Endpoint (2) | | | +----------+ | | +---------------+ | | ^ +----------|------|--<| Access Token | | | | | +--------|------|-->| EndPoint | | | | | | | | +---------------+ | | v | | | | | Session | | | +----------+ | | | | | Management | | | | | | | | | | Endpoints | + | |client |<-----(4)-+ | | | +---------------+ | | |servlet |>-----(5)---+ | +----------------------+ | | | | | | | | +----------------------+ | | | | | Profile API/ | | | | | | UserInfo Endpoint| | | |<--------------------|-----<| | | | |>--------------------|----->| | | +----------+ | +----------------------+ | | | | | +----------------------------------+ 3.1.5.1. Authorization Code Flow Request The authorization request parameter values are constrained as follows. response_type A space delimited, case sensitive list of string values (Pending OAuth 2.0 changes). The value MUST include "code" and "id_token" and to request an access and ID Token from the session. Sakimura, et al. [Page 10] Abbreviated-Title July 2011 Following is a non-normative example of a request using query parameters serialization: GET /authorize?scope=openid&response_type=code%20id_token &client_id=s6BhdRkqt3 &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb Host: server.example.com 3.1.5.2. Authorization Code Flow Response When the "response_type" in the request includes "code", the Authorization Response MUST return the parameters defined in section 4.1.2 of OAuth 2.0 [OAuth.2.0]. In addition, when "response_type" includes "id_token", the ID token is retrieved from the token access endpoint. Following is a non-normative example of a response: HTTP/1.1 302 Found Location: https://client.example.com/cb?code=i1WsRn1uB1 3.1.5.3. Token Access Request The client uses the authorization code to make a request to the token access endpoint to retrieve an access and ID token. The request format is defined in section 4.1.3 of the OAuth 2.0 [OAuth.2.0] specification. Following is a non-normative example of a token access endpoint request: POST /token HTTP/1.1 Host: server.example.com Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW Content-Type: application/x-www-form-urlencoded grant_type=authorization_code&client_id=s6BhdRkqt3& code=i1WsRn1uB1&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb 3.1.5.4. Token Access Response The access and ID token is returned in the response. The request format is defined in section 4.1.4 of the OAuth 2.0 [OAuth.2.0] specification. Sakimura, et al. [Page 11] Abbreviated-Title July 2011 Following is a non-normative example of a token access endpoint response: HTTP/1.1 200 OK Content-Type: application/json Cache-Control: no-store { "access_token":"SlAV32hkKG", "token_type":"JWT", "expires_in":3600, "refresh_token":"8xLOxBtZp8", "id_token":"jwt_header.jwt_payload.jwt_crypto" } 3.1.6. 4th Party Native Applications Fourth party native applications involve four parties: 1) the user, 2) the native (desktop) application, 3) the authorization server, and 4) the client servlet web application. The native application uses protected resources from a client servlet but it integrates with authentication services from the authorization server directly. The native application directs the user to perform authentication at the authorization server to obtain access and ID tokens. The tokens can then be used to access protected resources at the web servlet client. The process of obtaining an ID Token for the native application is very similar to that of using the code authorization (web server) flow method. However, the target audience of the ID Token is not the native application, but that of the client servlet. The client needs to indicate the target audience for the ID Token by setting the "id_token_audience" parameter in the authorization request to that of the identifier of the client servlet. Sakimura, et al. [Page 12] Abbreviated-Title July 2011 +-----------------------------+ +----------------+ | | | | | Authorization | | Native App | | Server | | | | | | | | +--------------------+ | | |>------------------|----->| Authorization | | | |<------------------|-----<| Endpoint | | | | | | | | | | | | | | | | | +--------------------+ | | | | | Access Token | | | |>------------------|----->| Endpoint | | | |<------------------|-----<| | | | | | | | | | | | +--------------------+ | | |>------------------|----->| Session Mgmt | | | |<------------------|-----<| Endpoints | | | | | | | | +----------------+ | | | | ^ | | | | | | +--------------------+ | v | | +----------------+ | | | Client | +-----------------------------+ | Servlet | | | +----------------+ When accessing protected resources at the client servlet, the native application sends the ID Token as an Auth HTTP header in the request. The client servlet can check the validity of the ID Token by verifying the cryptographic information or by sending the token to the check session token endpoint. GET /resource1 Auth: idtoken_jwt_header.idtoken_jwt_payload.idtoken_jwtcrypto Host: servlet.example.com 3.1.6.1. Browser Load Some native applications may wish to start an authenticated browser session for the same user. The native application starts a browser with the location of the client servlet and passing an ID Token as a query parameter. The client servlet immediately initiates a request to the refresh session endpoint with the ID Token. The user may need to reauthenticate at the authorization server. The client servlet Sakimura, et al. [Page 13] Abbreviated-Title July 2011 then gets an ID Token that is session synchronized with the authorization server. +--------------------------+ +------------+ +-----------+ | | | | | | | Authorization Server | | Native App |>---->|User-Agent | | | | | | | | +------------------+ | | | | |>------|--->| Session Refresh | | | | | |<------|---<| Endpoint | | +------------+ +-----------+ | | | | ^ ^ | +------------------+ | | | | | v v | | +--------------------------------+ | | | | | | | Client Servlet | | | | | | | +--------------------------------+ +--------------------------+ GET /refesh_token?state=bar&redirect_uri=https://foo.com/oauth2callback&id_token=$id_token // never uses immediate mode here, to allow login Host: www.example.com Response: HTTP/1.1 302 Found Location: https://foo.com/oauth2callback?state=bar&session=$new_id_token 3.2. Session Management Endpoints To manage a session, the client sends a request to the session management endpoints at the authorization server. The session management endpoints at the authorization server are: Refresh Session Refreshes an expired ID Token Check Session Get a plain text JSON structure from a ID Token End Session Ends a session Sakimura, et al. [Page 14] Abbreviated-Title July 2011 3.2.1. Refresh Session To refresh an ID Token that has expired, the client sends a request to the Refresh Session endpoint with an ID Token. A new ID Token is returned in JWS format. Request Parameters: id_token REQUIRED. A previously issued ID Token from an authorization request. The ID Token MAY be expired. state REQUIRED. An opaque value used by the Client to maintain state between the request and callback. If provided, the Authorization Server MUST include this value when redirecting the user-agent back to the Client. Clients are strongly advised to use this variable to relate the request and response. redirect_uri REQUIRED. An absolute URI to which the authorization server will redirect the user-agent to with the new ID Token. Response: The response is a new ID Token. In a typical HTTP binding, an HTTP 302 redirect to the specified redirect_uri in the request with a new ID Token. id_token A new ID Token The following is a non-normative session refresh request: Sakimura, et al. [Page 15] Abbreviated-Title July 2011 Request: GET /op/refresh_session?id_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiIsImtpZCI6 ImNsaWVudC5leGFtcGxlLmNvbSJ9.eyJpc3N1ZXIiOiJodHRwOlwvXC9zZXJ2ZXIuZXhhbXBs ZS5jb20iLCJjbGllbnRfaWQiOiJjbGllbnQuZXhhbXBsZS5jb20iLCJhdWRpZW5jZSI6ImNsa WVudC5leGFtcGxlLmNvbSIsImlkIjoidXNlcl8yMzQyMzQiLCJleHAiOjEzMDM4NTI4ODB9.a JwagC6501Da-zK-X8Az9B-Y625aSEfxVuBpFEDjOxQ &state=bar&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fidtoken_cb Host: server.example.com Response: HTTP/1.1 302 OK Location: http://client.example.com/idtoken_cb#id_token=eyJ0eXAiOiJKV1QiLCJh bGciOiJIUzI1NiIsImtpZCI6ImNsaWVudC5leGFtcGxlLmNvbSJ9.eyJpc3N1ZXIiOiJodHRwO lwvXC9zZXJ2ZXIuZXhhbXBsZS5jb20iLCJjbGllbnRfaWQiOiJjbGllbnQuZXhhbXBsZS5jb20 iLCJhdWRpZW5jZSI6ImNsaWVudC5leGFtcGxlLmNvbSIsImlkIjoidXNlcl8yMzQyMzQiLCJle HAiOjEzMDM4NTI4ODB9.aJwagC6501Da-zK-X8Az9B-Y625aSEfxVuBpFEDjOxQ&state=bar& expires_in=3600 3.2.2. Check Session For clients that are not capable of dealing with JWS signed ID Tokens, they can send the ID Token to the Check Session endpoint. It will validate the ID Token and return a plain text JSON structure of the ID Token. Request Parameters: id_token REQUIRED. A previously issued ID Token Response: The response body is a plain text JSON structure of the claims in the ID token. If the ID token is a JWS [JWS], then it is the base64url decoded payload of the signed ID Token. In a typical HTTP binding, the response is a HTTP 200 response code with the content-type header set to "application/json". The following is a non-normative example of a check session request: Sakimura, et al. [Page 16] Abbreviated-Title July 2011 Request: POST /op/check_session?id_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiIsImtpZCI6 ImNsaWVudC5leGFtcGxlLmNvbSJ9.eyJpc3N1ZXIiOiJodHRwOlwvXC9zZXJ2ZXIuZXhhbXBs ZS5jb20iLCJjbGllbnRfaWQiOiJjbGllbnQuZXhhbXBsZS5jb20iLCJhdWRpZW5jZSI6ImNsa WVudC5leGFtcGxlLmNvbSIsImlkIjoidXNlcl8yMzQyMzQiLCJleHAiOjEzMDM4NTI4ODB9.a JwagC6501Da-zK-X8Az9B-Y625aSEfxVuBpFEDjOxQ Response: HTTP/1.1 200 OK Content-Type: application/json { "issuer":"http://server.example.com", "client_id","http://client.example.com", "audience", "http://client.example.com", "user_id":"user_328723", "exp":1303852880 } 3.2.3. End Session To end the session, the client sends an ID Token to the End Session endpoint. Upon receiving the request, the authorization server performs the logout flow for the user and then redirects the user- agent to the specified redirect_uri. Request Parameters: id_token REQUIRED. A previously issued ID Token state REQUIRED. An opaque value used by the Client to maintain state between the request and callback. If provided, the Authorization Server MUST include this value when redirecting the user-agent back to the Client. Clients are strongly advised to use this variable to relate the request and response. redirect_uri REQUIRED. An absolute URI to which the authorization server will redirect the user-agent. Response: The response is dependent on the particular binding. In HTTP binding, the response is a HTTP 302 redirect response to the redirect_uri specified in the request. The following is a non-normative session refresh request: Sakimura, et al. [Page 17] Abbreviated-Title July 2011 Request: GET /op/end_session?id_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiIsImtpZCI6 ImNsaWVudC5leGFtcGxlLmNvbSJ9.eyJpc3N1ZXIiOiJodHRwOlwvXC9zZXJ2ZXIuZXhhbX BsZS5jb20iLCJjbGllbnRfaWQiOiJjbGllbnQuZXhhbXBsZS5jb20iLCJhdWRpZW5jZSI6I mNsaWVudC5leGFtcGxlLmNvbSIsImlkIjoidXNlcl8yMzQyMzQiLCJleHAiOjEzMDM4NTI4 ODB9.aJwagC6501Da-zK-X8Az9B-Y625aSEfxVuBpFEDjOxQ &state=bar &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fendtoken_cb Host: server.example.com ... Authorization server performs logout flow ... Response: HTTP/1.1 302 OK Location: http://client.example.com/endtoken_cb?state=bar 3.3. Session Synchronization An ID Token is usually bound to a user's sign in session at the authorization server, but in some cases, such as offline access by a web server or native application, it may not be. ID Tokens obtained in the following scenarios are bound to a user's signed-in state at the authorization server: o Redeeming a code for an access and ID Token by way of indirect communication through the browser o Obtaining an access and ID Token in the authorization response through the browser o Obtaining an ID Token at the refresh session endpoint by submitting a previously issued ID Token ID Tokens obtained in the above manner are session synchronized. If an ID Token is obtained by submitting a refresh token at the access token endpoint, then the resulting ID Token is not bound to a user's sign in state at the authorization server. The client may be in offline mode or the user has logged out from the authorization server. If a session bound ID Token is desired, the client should obtain a new ID Token by sending a request to the refresh session endpoint. Sakimura, et al. [Page 18] Abbreviated-Title July 2011 4. IANA Considerations This document makes no request of IANA. Sakimura, et al. [Page 19] Abbreviated-Title July 2011 5. Security Considerations Sakimura, et al. [Page 20] Abbreviated-Title July 2011 6. Normative References [JWS] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer, J., Sakimura, N., and P. Tarjan, "JSON Web Signatures", April 2011. [JWT] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer, J., Sakimura, N., and P. Tarjan, "JSON Web Token", March 2011. [OAuth.2.0] Hammer-Lahav, E., Ed., Recordon, D., and D. Hardt, "OAuth 2.0 Authorization Protocol", May 2011. [OpenID.Core] Recordon, D., Sakimura, N., Bradley, J., de Medeiros, B., Jones, M., and E. Jay, "OpenID Connect Core 1.0", July 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Sakimura, et al. [Page 21] Abbreviated-Title July 2011 Appendix A. Acknowledgements Sakimura, et al. [Page 22] Abbreviated-Title July 2011 Appendix B. Document History [[ To be removed from the final specification ]] -01 o Consistency and cleanup pass, including removing unused references. -00 o Split from core when all optional features were removed. Sakimura, et al. [Page 23] Abbreviated-Title July 2011 Authors' Addresses Nat Sakimura Nomura Research Institute, Ltd. Email: n-sakimura@nri.co.jp John Bradley Protiviti Government Services Email: jbradley@mac.com Michael B. Jones Microsoft Corporation Email: mbj@microsoft.com Breno de Medeiros Google Email: breno@google.com Chuck Mortimore Salesforce Email: cmortimore@salesforce.com Edmund Jay MGI1 Email: ejay@mgi1.com Sakimura, et al. [Page 24]