A New Public Key Cryptosystem based on Matrices

This paper describes a new method for authentication and integrity where the ciphertext is obtained using block upper triangular matrices with elements in p Z , in which the discrete logarithm problem (DLP) defined over a finite group is used. In the proposed public key cryptosystem, the encryption requires very few operations and decryption is equivalent to the DLP and, finally, the signature scheme presented is based on the ElGamal signature scheme and requires the original message in order to verify the signature. With this system we get a large key space without increasing the difficulty of the problem.