new cryptographic protocol?



Hello,
I am looking for a cryptographic protocol for anonymous, unlinkable authentication and selective disclosure of identity attributes.
Also, the protocol shall be based on elliptic curves.

What I mean is basically a merge of
1. the DAA (Direct anonymous attestation) protocol from Chen/Morrissey/Smart
(see http://eprint.iacr.org/2009/198.pdf)

2. the U-Prove protocol from S. Brands (is now IP of Microsoft)
(see www.credentica.com or https://connect.microsoft.com/site642/Downloads/DownloadDetails.aspx?DownloadID=26953 )

Does such a protocol already exist?

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Thanks,
Rainer

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