Sending an encrypted key pair and a secret shared by two devices to a trusted intermediary

摘要

Key exchange methods, apparati, and computer-readable media for a cryptographic communication system. The system, which employs a novel combination of multiple channel communication, symmetric cryptography, and asymmetric cryptography, allows an entity A to bootstrap the exchange of cryptographic secrets EQB to a second entity B through an alternate communication channel 30 for the transmission of a cryptographically secure message M. The system is secure against various passive and active attacks. The encryption key transfer is briefly vulnerable to man-in-the-middle attacks, but this can be prevented in preferred embodiments.

主权项

1. At least one non-transitory computer-readable medium containing computer program instructions for performing the steps of:
a first entity A generates a private key/public key pair to be used by a second entity B in subsequent communications with A, where B has been selected by A to receive confidential communications from A; A encrypts said key pair with P, where P is a secret shared by A and B; A sends the encrypted key pair to a trusted intermediary L; A encrypts a message M, and sends the encrypted M to B over a communications channel; B retrieves B's private key/public key pair from L, along with means to decrypt M; and B decrypts M using B's private key retrieved from L and said means to decrypt retrieved from L.