US Patent 11652644 Quantum-resistant double signature system

A method includes verifying a digital signature on a dual-signed message by a relying party computing system. Verifying the digital signature on the dual-signed message includes generating a cryptographic hash of content identified in the dual-signed message and signing the cryptographic hash using public key of a signing party computing system to generate a verifying hash. Verifying the digital signature on the dual-signed message further includes comparing the verifying hash to a value of the dual-signed message. Verifying the digital signature on the dual-signed message further includes, responsive to the verifying hash matching the value of the dual-signed message, determining that the digital signature on the dual-signed message is valid. The method further includes identifying an attribute of the dual-signed message by the relying party computing system. The method further includes, based on identifying the attribute, receiving a verification notification for the dual-signed message by the relying party computing system.