Public key encryption and decryption circuitry and method

Abstract

A high-speed public key cryptosystem is constructed for the encryption and decryption of digital data blocks, the creation and verification of digital signatures, and the creation of verifiable random number sequences. The encryption and decryption techniques employ a public key K constructed as the matrix product of a randomly generated nonsingular matrix M, and a rectangular template matrix T having row identifiers imbedded therein for selecting rows of a matrix M-1 that participate during decryption. Encrypting of a plaintext block, is achieved by converting the block to a nonlinear row selector code used to select rows of K. Columns of the selected rows are then added modulo-2 to produce a block if ciphertext. Deciphering the ciphertext is an iterative process wherein successive row identifiers and plaintext bits are unmasked by selecting rows of matrix M-1 in accordance with the bit states of the ciphertext, and adding columns of the selected rows modulo-2 to produce an intermediate block of data containing 2 plaintext bits and a row identifier used to select a row of key T, which is then added modulo-2 to the intermediate block to reveal the next two bits of plaintext and the next row identifier. A public key consisting of a single, noninvertible, binary matrix and a private key consisting of a pair of binary matrices, one or which is singular and the other nonsingular.