From: Michael Froomkin <froomkin@law.miami.edu>
Date: Thu, 15 Feb 1996 15:58:55 +0800
To: cypherpunks <cypherpunks@toad.com>
Subject: anonymous age credentials, sharing of
Message-ID: <Pine.SUN.3.91.960214143233.28807O-100000@viper.law.miami.edu>
MIME-Version: 1.0
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Suppose Alice is a CA who issues anonymous age credentials.
Bob is 15
Carol is 25

Carol gets a legitimate anonymous age credential from Alice bound to an 
anonymous public key generated for this purpose.  Carol then gives the 
key pair to Bob.  Bob uses to do things only adults are legally permitted 
to do.  (It's not bound to Carol's everday keypair because that's not 
anonymous....)

What can stop Bob and Carol from subverting a scheme that relies on 
anonymous age creditials in this manner?

If the answer is "nothing" this might mean that purveyors of "adult" 
material might have no defense against a law requiring that they collect a 
True Name + age creditential....

A. Michael Froomkin        | +1 (305) 284-4285; +1 (305) 284-6506 (fax)
Associate Professor of Law | 
U. Miami School of Law     | froomkin@law.miami.edu
P.O. Box 248087            | http://www.law.miami.edu/~froomkin
Coral Gables, FL 33124 USA | It's warm here.