The paper introduces a new method for public encryption in which the enciphering process is performed as a generation of the coeffi cients of some cubic equation and the deciphering process is solving the equation. Security of the method is based on a difficulty of the factoring problem, namely, difficulty of factoring a composite number n that serves as a public key. The private key is the pair of primes p and q such that n = pq. The deciphering process is performed as solving cubic congruence modulo n. Finding roots of cubic equations in the fi elds GF(p) and GF(q) is the first step of the decryption. The paper also describes a method for solving cubic equations defi ned over prime fi nite fi elds. Introduced method of public encryption is applied for development of deniable encryption protocol, which is resistant against two-sided coercive attacks.
cryptography, encryption, public key encryption, deniable encryption, public key, probabilistic encryption, factorization problem, cubic equation, prime finite field.
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