Patent ID: 6909783

Claim:
A method for using a fixed-length one-one pad for sending a variable-length enciphered transmission of a message in a first alphabet consisting of n distinct symbols to a recipient using a second alphabet consisting of n distinct symbols, the method comprising: distributing identical matrices to both a sender and a recipient, wherein the matrix consists of m rows and n columns, wherein each row in the matrix contains every symbol of the second alphabet, and wherein the symbols of the second alphabet are randomly distributed in each row; distributing identical symbol arrays to both the sender and the recipient, wherein each array consists of n elements, and wherein each array contains every symbol of the first alphabet; selecting an initial row index and an initial column index corresponding to a symbol in the matrix; setting a current row index to the initial row index and a current column index to the initial column index; for each symbol in the message and in a corresponding ciphertext, adding the symbol's position in the array to the current column index, subtracting n from the current column index if it no longer corresponds to a valid matrix column, setting the ciphertext symbol to the symbol in the matrix at the current row index and current column index, incrementing the current row index, and subtracting m from the current row index if it no longer corresponds to a valid matrix row; sending the ciphertext, the current row index, and the current column index to the recipient.