International Business Machines Corporation

Robert R Enderlein

Jan Leonard Camenisch

Gregory Neven

Anja Lehmann

Stephan Krenn

A method, computer program product, and system for providing verification processes associated with a commitment-based authentication protocol are described. A request by a user for access to one or more resources is received, and a presentation policy is transmitted to the user indicating required credentials. A commitment to a revocation handle is received, including an indication of an associated Sigma protocol executed by the user. A challenge value selected from a challenge value set associated with the associated Sigma protocol is transmitted to the user. Based on the selected challenge value, a presentation token and a value parameter that is distinct from the presentation token are received from the user. Based on a determination as to whether the presentation token and value parameter are valid in accordance with the associated Sigma protocol, access for the user to the one or more resources is granted to the user or prevented.

Traitor tracing for obfuscated 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.

Privacy-preserving attribute-based credentials

A user computer generates a secret cryptographic key through communication with a server. A secret user value is provided at the user computer. A secret server value is provided at the server with a check value which encodes the secret user value and a user password. In response to input of an input password, the user computer encodes the secret user value and the input password to produce a first value corresponding to said check value, and communicates the first value to the server. The server compares the first value and check value to check whether the input password equals the user password. If so, the server encodes the first value and secret server value to produce a second value and communicates the second value to the user computer. The user computer generates the secret cryptographic key by encoding the second value, the input password and the secret user value.

Password-based generation and management of secret cryptographic keys

Methods and apparatus are provided for generating a secret cryptographic key of a user computer connectable to a server via a network. A secret user value is provided at the user computer. A secret server value is provided at the server with a check value which encodes the secret user value and a user password. The user computer encodes the secret user value and an input password to produce a first value corresponding to said check value, and communicates the first value to the server. The server compares the first and the check values to check whether the input password equals the user password. If so, the server encodes the first and the secret server values to produce a second value and communicates the second value to the user computer. The user computer generates the secret cryptographic key by encoding the second value, the input password and the secret user value.

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Adliswil, Switzerland

Robert R Enderlein