[OpenID] OpenID Assertion Quality Extension - Draft

Thu Nov 30 22:22:05 UTC 2006

Just to weigh in here...

>
> Paul Madsen wrote:
>> Hi George, for your use case below, why would not the RP just ask  
>> for the user to be up-authenticated at the desired higher level  
>> when necessary?
> So in the draft... how does the RP ask for the user to be "up- 
> authenticated"?  The authentication request parameters do not in  
> any way indicate a previous authentication, and the extension  
> parameters also don't include any way to indicate a previous  
> authentication.  That is what I really meant by the authentications  
> being "standalone".  The RP may relate the two authentications in  
> some way because it requested both.  Maybe that's good enough.
Basically, you would require the second method with a max_age of "0"  
- which, assuming the RP honors the request,  would tell the RP to re- 
authenticate the user with the requested method.

>>
>> Are you asking whether the RP should be allowed to ask the user to  
>> re-present their URI in order for this to happen? And thereby  
>> effectively treating each event as disconnected/standalone?
> Ideally, the user would not be able to change their URI when being  
> re-challenged based on max_auth_age but I guess the RP should make  
> sure to code for that edge case.
Agreed - it's the RPs choice.

>>
>> Wrt combinations, I know from experience that the alternative to  
>> allowing for RPs to specify combinations is a combinatorial  
>> explosion in the number of  mechanism identifiers.
> I agree that the combinations can explode... but they are also  
> useful.  For example to hack my account you need both my "password"  
> and my "hardotp". That's two "secrets" that need to be determined  
> for my account to be compromised. (Not that this doesn't stop  
> phishers).
>

Actually, this could be pretty simple to implement:

Replace  openid.aqe.preferred_auth_mode with the following:

	openid.aqe.auth_factor1
Optional: The method of authentication the RP would like the OP to  
perform, or in the case of a multi-factor authentication, the first  
method that the RP would like the OP to perform. The mode should  
match one of the advertised values in the XRDS. If this is not  
specified, then any authentication method is acceptable.

Value: Comma-delimited list of "none", "password", "pin",  
"fingerbio", "handbio", "hardotp", "irisbio", "otherbio",  
"smartcard", "softotp", "voicebio"

Note: The OP should attempt to authenticate the user with the most  
secure mode requested. For example, if the OP has determined that  
their voicebio method is stronger than their password method and the  
RP requests either "voicebio or password", the OP should strive to  
authenticate the user by "voicebio" when possible. If the two modes  
are considered equally strong, then it is the choice of the OP  
regarding which one or ones to authenticate against. OPs should note  
that authenticating a user by a non-preferred method may result in an  
RP denying access.

	openid.aqe.auth_factor2
Optional: In the case of a multi-factor authentication, the second  
method that the RP would like the OP to perform. The mode should  
match one of the advertised values in the XRDS. If this is not  
specified, then any authentication method is acceptable. If this is  
not specified, it is assumed that the RP is requesting only a single  
factor for authentication. The OP will not use the same method for  
this factor as was used in any previous factors. For example, if the  
first factor is a password, the second factor cannot also be a password.

Value: Comma-delimited list of "none", "password", "pin",  
"fingerbio", "handbio", "hardotp", "irisbio", "otherbio",  
"smartcard", "softotp", "voicebio"

Note: The OP should attempt to authenticate the user with the most  
secure mode requested. For example, if the OP has determined that  
their voicebio method is stronger than their password method and the  
RP requests either "voicebio or password", the OP should strive to  
authenticate the user by "voicebio" when possible. If the two modes  
are considered equally strong, then it is the choice of the OP  
regarding which one or ones to authenticate against. OPs should note  
that authenticating a user by a non-preferred method may result in an  
RP denying access.

	openid.aqe.auth_factor3
... you can figure how it would continue. There are very few use  
cases that would use more than two factors.

So, in this case, if you want the user to authenticate with two  
factors, first with a password and second with a securID or voice  
biometric print...

openid.aqe.auth_factor1 = "password"

openid.aqe.auth_factor2 = "hardotp", "voicebio"

conversely, if you want two factors, which could be any combination  
of password, hardotp or voicebio in any combination:

openid.aqe.auth_factor1 = "hardotp", "voicebio", "password"

openid.aqe.auth_factor2 = "hardotp", "voicebio", "password"

the response from the OP, assuming that it followed the request from  
the RP would look like

openid.aqe.auth_factor1 = "password"

openid.aqe.auth_factor2 = "hardotp"

I would think that this is clear enough that we could make the small  
change to the spec to allow for this type of methodology.

Thoughts?

- Avery

> Thanks,
> George
>
>>
>> Paul
>>
>> George Fletcher wrote:
>>> +1 simple and straight forward
>>>
>>> Just curious about uses cases where the required authentication  
>>> level changes over time.  For instance, a use case where to view  
>>> my stock portfolio just requires "password", but doing a trade  
>>> requires "voicebio".  Is the expectation that authentication  
>>> events can be treated as "standalone"? or that it's the RP's  
>>> responsibility to manage the combinations based on the identifier?
>>>
>>> One final question... Is it valuable to provide a way to request  
>>> two or more authentication methods be employed in the  
>>> authentication event?  For example, administrators of a site must  
>>> use both "password" and "hardotp".  Everyone else just needs  
>>> "password".
>>>
>>> Thanks,
>>> George
>>>
>>>
>>> _______________________________________________
>>> general mailing list
>>> general at openid.net
>>> http://openid.net/mailman/listinfo/general
>>>
>>>
>>>
>>
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> general at openid.net
> http://openid.net/mailman/listinfo/general

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