[Freedombox-discuss] identicons are not strong crypto [was: Re: Tap-to-share PGP key exchange]

[Alex Stapleton]

On 30 Sep 2011, at 17:17, Daniel Kahn Gillmor wrote:

> On 09/30/2011 11:09 AM, Alex Stapleton wrote:
>> http://haacked.com/archive/2007/01/22/Identicons_as_Visual_Fingerprints.aspx
> 
> This link seems to come up often when talking about fingerprint
> comparisons.  I am not convinced it is a good idea from a cryptographic
> standpoint.
> 
> Good for easy visual distinction between cooperating parties is not the
> same thing as a strong cryptographic assurance against a malicious
> impersonator.
> 
> Identicons are a neat idea, but without a lot more defensively-oriented
> analysis, they're not something to be used in a critical context like
> strong establishment of identity.

The lack of a secure, well audited visual hashing thing is a bit of a problem with this approach I agree :)

Personally I would be comfortable with using something like that with the vast majority of my trust relationships. However, I get the need for something more secure, and I am not especially convinced reading long hex strings is especially secure :)

What about sending an HMAC with a randomly generated, or user entered key on each device?