Patent ID: 9455832
Filing Date: 2016-09-27
CPC Classification: H04L

Claim Text:
1. A method for generating a signature of a message in a cryptographic communication system, said method comprising: a cryptographic processor of a first entity in said cryptographic communication system dividing a message into a plurality of portions, a first portion of said message to be visible, a second portion of said message to be hidden and confidential, and a third portion of said message to be hidden and recoverable, said second portion recoverable only by one or more verifying entities possessing a private key specific to said one or more verifying entities, the private key having a corresponding public key available to said first entity, said corresponding public key being specific to the verifying entity, said third portion being recoverable by any entity having access to a public key of said first entity, wherein each of said first entity and said one or more verifying entities are separate information processing systems communicatively coupled to each other via at least one communication link; said cryptographic processor generating an ephemeral key pair; said cryptographic processor constructing a secret value using said ephemeral key pair and public keys of a plurality of verifying entities; said cryptographic processor generating a first encryption key using said secret value such that presence of said plurality of verifying entities is required to provide corresponding private keys possessed by respective ones of said verifying entities to generate a corresponding decryption key; said cryptographic processor encrypting said second portion of said message using said first encryption key to generate a first signature component, said decryption key being required to decrypt said second portion of said message from said first signature component; said cryptographic processor generating a second signature component by combining said first signature component, said first portion of said message and a private key of said first entity using a signing equation; said cryptographic processor generating a third signature component by generating a second encryption key and encrypting said third portion of said message using said second encryption key; said cryptographic processor preparing the signature comprising said first, second, and third signature components and said first portion of said message; and sending said message and said signature to at least said one or more verifying entities.