!!! Overview
[{$pagename}] is a [Credential] created by a system a [End-User] [entity] uses uses a different "digital [pseudonym]" with each [Service Provider]. 



[{$pagename}] was described in SECURITY WITHOUT IDENTIFICATION: TRANSACTION SYSTEMS TO MAKE BIG BROTHER OBSOLETE by DAVID CHAUM in [1985|Year 1985]


[{$pagename}] can be thought of as a [Digital Signature] by the Issuer on a list of attribute-value pairs, e.g. the list 
{{{(fname=”Alice”, lname=”Anderson”, bdate=”1977/05/10”, nation=”DE”)}}}
The most straightforward way for the User to convince a [Verifier] of her list of [attributes] would be to simply transmit her [credential] to the [Verifier]. 

This approach has a number of disadvantages, most notably:
* that the User has to reveal all of her [attributes] so that the [Verifier] can check the [Digital Signature];
* that the [Verifier] can reuse the [credential] to [impersonate|Impersonation] [Alice] wrt other [Verifiers].
With anonymous credentials, the User never transmits the credential itself, but rather uses it to convince the [Verifier] that her [attributes] satisfy certain properties – without leaking anything about the [credential] other than the shown properties. 
This has the obvious advantage that the [Verifier] can no longer reuse the [credential] to [impersonate|Impersonation] [Alice]. 


!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
----
* [#1] - [SECURITY WITHOUT IDENTIFICATION: TRANSACTION SYSTEMS TO MAKE BIG BROTHER OBSOLETE|https://www.cs.ru.nl/~jhh/pub/secsem/chaum1985bigbrother.pdf|target='_blank'] - based on information obtained 2019-01-17-