摘要 |
A cipher system is disclosed in which each character of a plaintext alphabet has associated with it a randomly distributed collection of integers (5) of a given length. These collections of integers are secretly shared by a sender and receiver pair. The plaintext characters of a message are sequentially coded by randomly selecting representatives from the integer collections (3) corresponding to the plaintext characters. To this sequence of concatenated integers, regarded as a single integer, is added (7) a random integer of length equal to that of the coded-for-message integer string (6). This random integer is taken from a string of random digits shared by the sender and receiver. The indexing of the random integer in the digit string is transmitted (9) as part of the cryptogram. The summed random integer plus the coding integer string is transmitted (9) as the body of the cryptogram. To decrypt, the receiver subtracts (7) the random integer from the transmitted integer, breaks up the remaining integer into the blocks numerically coding the plaintext characters and retrieves the plaintext characters of the message. Provision is made for further obscuring the cryptogram integer (10). |