CRYPTOGRAPHIC SYSTEM ALLOWING ENCRYPTED COMMUNICATION BETWEEN USERS WITH A SECURE MUTUAL CIPHER KEY DETERMINED WITHOUT USER INTERACTION

摘要

A secret key generator for a trusted authority means in a cryptographic system comprising means for receiving a publicly-known user identity IDA for a user A; and further comprising secret key generator means for transforming the publicly-known user identity IDA into secret key sA for the user A with the inverse of the exponentiation function $that\; is\; solved\; for\; sA,\; where\; a\; is\; a\; publicly-known\; base\; parameter,\; where\; m\; is\; a\; publicly-known\; modulus\; parameter\; and\; m\; =\; p1\; .\; p2,\; ...\; ,\; pr,\; and\; where\; p1,\; p2,\; ...,\; pr\; are\; secret\; system\; prime\; numbers.\; The\; inverse\; of\; the\; exponentiation\; function\; is\; infeasible\; to\; compute\; in\; order\; to\; calculate\; the\; secret\; key\; sA\; without\; knowing\; the\; prime\; numbers\; p1,\; p2,\; ...,\; pr.\; The\; secret\; key\; sA\; enables\; user\; A\; to\; communicate\; securely\; to\; a\; user\; B\; having\; publicly-known\; user\; identity\; IDB\; with\; a\; mutual\; secure\; cipher\; key\; KAB,\; defined\; by\; the\; equation:$ The\; mutual\; secure\; cipher\; key\; KAB\; is\; determined\; without\; previous\; interaction\; with\; the\; user\; B.$$