Slashdot Mirror
Digital Credentials Offer Enhanced Privacy
John Q Random writes "Stefan Brands's company credentica.com announced their U-Prove library and SDK implementing ID tokens — also known as digital credentials or private credentials. (Private Credentials are a cool PKI replacement and anonymous e-cash tech that allows you to prove certified attributes like age, credit rating, group membership, etc. without revealing who you are; to allow you to have a digital life without the digital dossier effect inherent in a central databases.) Following this announcement, Adam Back announced credlib, an open source implementation of Brands credentials (and the older more basic Chaum certificates). These developments relate to recent news from IBM's Zurich labs on their identity-mixer project (previously discussed on Slashdot) that is based on the less efficient Jan Camenisch and Anna Lysyanskaya credentials."
They have an anti-lending option. Here's how it works: the credential can have multiple private keys, one of which has to be random and the others of which can be secrets you would not be happy to sell to a youngster. (Say like your credit card number, or any other info that could be risky to lend to someone). Without all of the private keys you cant use the credential, so the would be lender, or reseller cant transfer the credential without revealing secrets chosen to be risky to share.
The CA or credential issuer, he sees secrets when the credential is issued, however you trust him not to abuse those secrets (and maybe you paid him with the same credit card number eg). However due to the crypto magic the CA cant observe nor trace your uses of the credential back to you even with full collusion with relying parties.
In fact the privacy is unconditionally secure and the user has full control and doesnt have to trust anyone (not CA, not relying parties, etc) only that the software of his credential wallet software is correctly implemented. This software would typically be open source and peer reviewed.