DEVICE AND METHOD FOR GENERATING A SESSION KEY

摘要

A device and method are provided for establishing a session key between two entities of a communication network that may be highly heterogeneous in terms of resources. The method, based on the Diffie-Hellman (DH) algorithm, provides for the delegation to assistant nodes of the network of the cryptographic operations required for the computations of the DH public value and of the DH session key for the node which is constrained in terms of resources.

主权项

1. In a communication network comprising a plurality of communicating entities, a method for establishing a session key according to the Diffie-Hellman protocol between a source entity with a source private value ‘a’ and a target entity with a target private value ‘b’ and a target public value ‘gb mod p’, the method comprising the steps of:
selection of ‘n’ assistant entities among the plurality of communicating entities; decomposition of the source private value ‘a’ into ‘n’ fragments; enciphering of each fragment ‘n’ of the source private value; transmission to each assistant entity of an enciphered fragment among the ‘n’ enciphered fragments of the source private value, each assistant entity receiving a different enciphered fragment; computation by each assistant entity of a fragment of source public value with the received enciphered fragment of the source private value; transmission of the computed fragment of source public value to the target entity by each assistant entity; computation by the target entity of the source public value with the received fragments of source public value; transmission to the ‘n’ assistant entities of a fragment of the target public value; computation by each assistant entity with the enciphered fragment of the source private value, of an exponentiation of the received target public value; and transmission of each exponentiation to the source entity.