Re: [OAUTH-WG] Refresh Tokens

Eran Hammer-Lahav <eran@hueniverse.com> Thu, 11 August 2011 19:34 UTC

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From: Eran Hammer-Lahav <eran@hueniverse.com>
To: Anthony Nadalin <tonynad@microsoft.com>, Dick Hardt <dick.hardt@gmail.com>
Date: Thu, 11 Aug 2011 12:35:07 -0700
Thread-Topic: [OAUTH-WG] Refresh Tokens
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Subject: Re: [OAUTH-WG] Refresh Tokens
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Section 1.5 already covers refresh tokens. There are many use cases for refresh tokens. They are basically a protocol feature used to make scalability and security more flexible. Anonymity was never part of their design, and by the nature of this protocol, is more in the domain of the resource server (based on what information it exposes via its API). In fact, your email if the first such suggestion of anonymity.

EHL

From: Anthony Nadalin <tonynad@microsoft.com<mailto:tonynad@microsoft.com>>
Date: Thu, 11 Aug 2011 11:15:28 -0700
To: Dick Hardt <dick.hardt@gmail.com<mailto:dick.hardt@gmail.com>>
Cc: "OAuth WG (oauth@ietf.org<mailto:oauth@ietf.org>)" <oauth@ietf.org<mailto:oauth@ietf.org>>
Subject: Re: [OAUTH-WG] Refresh Tokens

Many reasons, but none are explained in the specification

From: Dick Hardt [mailto:dick.hardt@gmail.com]
Sent: Thursday, August 11, 2011 10:51 AM
To: Anthony Nadalin
Cc: OAuth WG (oauth@ietf.org<mailto:oauth@ietf.org>)
Subject: Re: [OAUTH-WG] Refresh Tokens

My recollection of refresh tokens was for security and revocation.

security: By having a short lived access token, a compromised access token would limit the time an attacker would have access

revocation: if the access token is self contained, authorization can be revoked by not issuing new access tokens. A resource does not need to query the authorization server to see if the access token is valid.This simplifies access token validation and makes it easier to scale and support multiple authorization servers.  There is a window of time when an access token is valid, but authorization is revoked.



On 2011-08-11, at 10:40 AM, Anthony Nadalin wrote:


Nowhere in the specification is there explanation for refresh tokens, The reason that the Refresh token was introduced was for anonymity. The scenario is that a client asks the user for access. The user wants to grant the access but not tell the client the user's identity. By issuing the refresh token as an 'identifier' for the user (as well as other context data like the resource) it's possible now to let the client get access without revealing anything about the user. Recommend that the above explanation be included so developers understand why the refresh tokens are there.
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