RE: [OpenID] identify RP when it gets OpenID URL
I am keen for the RP to identify itself when it performs discovery – and I would love this feature to be in 2.0 before it is finalized. The proposal is very simple (to describe and to implement): RPs add a “From:” HTTP header field to HTTP requests made during the discovery phase. The underlying premise is that a user has many varied user-RP relationships, and it is easiest if the same OpenID URL can be used to access them all. The issue is how to support the varied relationships. Some OPs will support some variations, but no OP can support all possible variations (many are user-specific). Identifying the RP during discovery enhances the ability to choose the appropriate OP for a specific user-RP relationship. The need for this feature can be seen in the PAPE draft (§3 Advertising Supported Policies) and OpenID 2.0 draft (§12 Extensions). They support different OPs when authenticating to different RPs - but with very limited options, and with the RP in control of the choice. The user (via the server hosting their OpenID URL) should also be in control. http://openid.net/specs/openid-provider-authentication-policy-extension-1_0-02.html#advertising http://openid.net/specs/openid-authentication-2_0-12.html#extensions Both specify how a Yadis document can list multiple OPs, each associated with different OpenID protocol versions, understanding different OpenID extensions, and supporting different authentication policies. These details “aide in the process of a RP selecting which OP they wish to interact with”. The appropriate OP can only be chosen **by the RP** based on a very limited set of pre-defined xrd:Type URIs. When that works… great. When it doesn’t, the site hosting the OpenID URL should be able to choose the appropriate OP based on the RP’s identity. For that it needs the RP identity during discovery, hence the “From:” HTTP request header. Previously mentioned use cases: Alice wants to use a single OpenID URL and -- 1. She wants to use different OPs when logging in to different RPs. 2. An OP is not accessible to particular RPs (eg an internal company OP is not accessible by RPs on the Internet). 3. Different RPs whitelist different (non-overlapping) sets of OPs. 4. A particular RP requires PAPE support, which only Alice’s non-preferred OP supports. From: Manger, James H Sent: Wednesday, 17 October 2007 12:59 PM To: 'specs@openid.net' Subject: [OpenID] identify RP when it gets OpenID URL It can be useful to know who the Relying Party (RP) is during the discovery phase. That is, the RP should state their identify when they are looking up a user’s OpenID URL (Claimed Identifier). Use case: Alice wants to use different OPs for different RPs, while keeping the same URL (eg http://alice.example.net/). For instance, when logging into a service hosting her backups she wants to use an OP that requires a one-time password from a hardware token for each access. However, when leaving comments on blogs Alice wants to authenticate using an OP that only requires a password and uses a persistent cookie so she only has to log in once a day. Problem: Only one OP can be specified with a link rel=openid2.provider…/ element or in a Yadis document. [A Yadis document may be able to list many OPs, but I don’t think there is any mechanism for the RP to pick the right one.] Solution: The RP could include a From HTTP header when performing discovery. Instead of serving a static HTML page (or Yadis document) at http://alice.example.net/, the page could be dynamically generated based on the value of the From header. Suggested text for the authentication spec (draft 12): Add the following paragraph at the end of section 7.3 Discovery: “The Relying Party MUST include a From HTTP header field in each HTTP request made during discovery. The From field holds an email address for the RP (eg From: [EMAIL PROTECTED]) [RFC2616]. This enables the discovered information to vary based on the RP. The From field is not authenticated so it is not appropriate to use for access control.” Other solutions: The source IP address of the discovery request will often identify the RP, but this would be an unreliable mechanism due to proxies, clusters, load balancing, and changes at the RP. Separate user-supplied identifiers could be used, but that unnecessarily complicates the system for users. OPs can offer different authentication mechanisms based on the openid.return_to or openid.realm parameter in an authentication request. However, the user has less flexibility when they have to relying on OPs. ___ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
RE: [OpenID] identify RP when it gets OpenID URL
The User-Agent field does not have the right semantics. I hope that field could be used, for instance, to notice which Relying Parties are using a particular version of Janrain’s Java library for OpenID. It is probably reasonable for Bloglines, Google etc to identify themselves in the User-Agent field as they probably use proprietary purpose-built clients. Most OpenID RPs will not use proprietary clients. The From field feels more appropriate for this OpenID purpose. From: John Panzer [mailto:[EMAIL PROTECTED] Sent: Wednesday, 17 October 2007 2:36 PM To: Manger, James H Cc: specs@openid.net Subject: Re: [OpenID] identify RP when it gets OpenID URL Wouldn't User-Agent: be equivalent, and have prior art (feed readers such as Bloglines identify themselves via User-Agent)? Manger, James H wrote: … “The Relying Party MUST include a From HTTP header field in each HTTP request made during discovery. The From field holds an email address for the RP (eg From: [EMAIL PROTECTED]) [RFC2616]. This enables the discovered information to vary based on the RP. The From field is not authenticated so it is not appropriate to use for access control.” … ___ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
Re: [OpenID] identify RP when it gets OpenID URL
On 17/10/2007, Manger, James H [EMAIL PROTECTED] wrote: Other solutions: OPs can offer different authentication mechanisms based on the openid.return_to or openid.realm parameter in an authentication request. However, the user has less flexibility when they have to relying on OPs. If the primary aim is just to let the user set a policy on how carefully they should be authenticated when talking to particular RPs, why wouldn't this alternative be appropriate? You are trading complexity at the OP end for complexity at the discovery/delegation end. Or are you trying to address a slightly different problem? Maybe one of: 1. using an OP that is not publicly accessible for certain operations 2. using an RP that will only authenticate people using a particular OP. James. ___ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
Re: [OpenID] identify RP when it gets OpenID URL
On 16-Oct-07, at 7:58 PM, Manger, James H wrote: Use case: Alice wants to use different OPs for different RPs, while keeping the same URL (eg http://alice.example.net/). For instance, when logging into a service hosting her backups she wants to use an OP that requires a one-time password from a hardware token for each access. However, when leaving comments on blogs Alice wants to authenticate using an OP that only requires a password and uses a persistent cookie so she only has to log in once a day. I believe there's a cleaner way to address this, that would not complicate the things that Alice needs to know about the inner workings of OpenID (and without her having to use different identities for different purposes): The PAPE-enabled backup service requests that the OP authenticates Alice in a manner compliant with certain policies, that are satisfactory to Alice's security requirements for a backup service. Johnny ___ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
RE: [OpenID] identify RP when it gets OpenID URL
PAPE may be another approach (to support per-user per-RP login policies). It certainly will not always be “cleaner”. It is not a reason against enabling a discovery-based approach. This PAPE suggestion requires the RP and OP to implement what the user wants. A discovery-based approach only requires the web site hosting the user’s identifier to implement what the user wants. The PAPE-enabled backup service requests that the OP authenticates Alice in a manner compliant with certain policies, that are satisfactory to Alice's security requirements for a backup service. PAPE must be implemented by the backup service AND the OP. Alice’s policy must be expressible in PAPE’s language. The backup service must have a GUI for Alice to choose her security requirements. The backup service has to remember per-user login requirements – which is rather at odds with a main point of OpenID of the RP not having to be involved with how Alice is authenticated. Every other RP where Alice wants to tweak her login policy also needs to support this… Please don’t make this the only way to implement this style of feature. There have always been 4 entities in an OpenID login: the user (with a browser); the OP; the RP; and the web site hosting the user’s identifier. The last entity can simply be a static HTML page, which is a huge bonus. Identifying the RP to this entity enables (but doesn’t require) it to be more than a static page – when that is useful (ie for users, circumstances and functions where it turns out to be the easiest implementation point). _ From: Johnny Bufu [mailto:[EMAIL PROTECTED] Sent: Thursday, 18 October 2007 4:15 AM To: Manger, James H Cc: specs@openid.net I believe there's a cleaner way to address this, that would not complicate the things that Alice needs to know about the inner workings of OpenID (and without her having to use different identities for different purposes): The PAPE-enabled backup service requests that the OP authenticates Alice in a manner compliant with certain policies, that are satisfactory to Alice's security requirements for a backup service. From: Manger, James H Sent: Wednesday, 17 October 2007 12:59 PM To: 'specs@openid.net' Subject: [OpenID] identify RP when it gets OpenID URL … Add the following paragraph at the end of section 7.3 Discovery: “The Relying Party MUST include a From HTTP header field in each HTTP request made during discovery. The From field holds an email address for the RP (eg From: [EMAIL PROTECTED]) [RFC2616]. This enables the discovered information to vary based on the RP. The From field is not authenticated so it is not appropriate to use for access control.” … ___ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
[OpenID] identify RP when it gets OpenID URL
It can be useful to know who the Relying Party (RP) is during the discovery phase. That is, the RP should state their identify when they are looking up a user’s OpenID URL (Claimed Identifier). Use case: Alice wants to use different OPs for different RPs, while keeping the same URL (eg http://alice.example.net/). For instance, when logging into a service hosting her backups she wants to use an OP that requires a one-time password from a hardware token for each access. However, when leaving comments on blogs Alice wants to authenticate using an OP that only requires a password and uses a persistent cookie so she only has to log in once a day. Problem: Only one OP can be specified with a link rel=openid2.provider…/ element or in a Yadis document. [A Yadis document may be able to list many OPs, but I don’t think there is any mechanism for the RP to pick the right one.] Solution: The RP could include a From HTTP header when performing discovery. Instead of serving a static HTML page (or Yadis document) at http://alice.example.net/, the page could be dynamically generated based on the value of the From header. Suggested text for the authentication spec (draft 12): Add the following paragraph at the end of section 7.3 Discovery: “The Relying Party MUST include a From HTTP header field in each HTTP request made during discovery. The From field holds an email address for the RP (eg From: [EMAIL PROTECTED]) [RFC2616]. This enables the discovered information to vary based on the RP. The From field is not authenticated so it is not appropriate to use for access control.” Other solutions: The source IP address of the discovery request will often identify the RP, but this would be an unreliable mechanism due to proxies, clusters, load balancing, and changes at the RP. Separate user-supplied identifiers could be used, but that unnecessarily complicates the system for users. OPs can offer different authentication mechanisms based on the openid.return_to or openid.realm parameter in an authentication request. However, the user has less flexibility when they have to relying on OPs. James Manger ___ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
