Method for blockwise encryption/decryption using linear algebraic codes

摘要

Method for blockwise encipherment, decipherment in a cryptosystem. A message block (x) of n message symbols is enciphered into a cryptogram (Y) of length n. A first sub-block (x_A'), a selection (σ_A) of kn message symbols from the message block to be enciphered is converted into a code word (c) of length n with the aid of a k×n enciphering matrix (E) of rank k, which generates a randomly chosen error-correcting (n, k) linear code C. By means of a second sub-block (x_B'), formed by the n-k remaining message symbols (σ_B), a syndrome vector (s) of length n-k is determined, by means of which, from a given set of syndrome/error vectors (t), a unique error vector (z) of length n is determined which is then added to the code word to form the cryptogram (y).;Thanks to the method, the information rate between the sender and recipient is R=1, and blockwise and repeated enciphering is possible.