A U-Prove token is a type of credential similar to a PKI certificate that can encode attributes of any type, but with two important differences:

1) The issuance and presentation of a token is unlinkable due to the special type of public key and signature encoded in the token; the cryptographic “wrapping” of the attributes contain no correlation handles. This prevents unwanted tracking of users when they use their U-Prove tokens, even by colluding insiders.

2) Users can minimally disclose information about what attributes are encoded in a token in response to dynamic verifier policies. As an example, a user may choose to only disclose a subset of the encoded attributes, prove that her undisclosed name does not appear on a deny list, or prove that she is of age without disclosing her actual birthdate.

These user-centric aspects make the U-Prove technology ideally suited to creating the digital equivalent of paper-based credentials and the plastic ID cards in one’s wallet.

Microsoft has made available the foundational features of the technology by releasing the core U-Prove specifications under the Open Specification Promise. The core cryptographic scheme has been standardized in ISO/IEC 18370-2:2016 (opens in new tab) (Blind digital signatures — Part 2: Discrete logarithm based mechanisms).




Portrait of Karen Easterbrook

Karen Easterbrook

Sr Principal PM Manager

Portrait of Greg Zaverucha

Greg Zaverucha

Principal Software Development Engineer

Portrait of Christian Paquin

Christian Paquin

Principal Research Software Engineer