US Patent 10079686 Privacy-preserving attribute-based credentials

The invention relates to an obfuscated program logic of machine executable instructions and a hardcoded cryptographic signing key. The obfuscated program logic further comprising a hardcoded first attribute value wherein execution of the machine executable instructions by the processor causes the obfuscated program logic to receive a request and in response to receiving the request evaluate whether the request is related to the hardcoded first attribute value. In case the request is related to the hardcoded first attribute value, then computing with the hardcoded first attribute value a response to the request and computing with the cryptographic signing key a signature, wherein the signature certifies the request for which the response was computed and certifies the authenticity of the response. Then generating and returning a presentation token comprising the response and the signature, and providing the presentation token to a receiver computer system.