PRIVATE-KEY ALGEBRAIC-CODE ENCRYPTION WITH ERRORS UP TO (D(MIN)-1) OFTHE CODE

In most algebraic-code cryptosystems errors are added to the encoded p laintext to form the ciphertext. The number of added errors is usually less than or equal to the error-correcting capability of the code. In this paper we propose a method that permits the addition of almost do uble the number of these errors. The idea is based on the fact that li near codes can correct twice as many erasures as errors. A method for erasure creation, detection and correction is devised. Such an approac h will allow for the addition of a number of errors that can not be co rrected without side information about their position. This approach w ill result in a further increase in the security of these systems comp ared to systems with errors only. Based on this idea, a private-key cr yptosystem with simple codes and permutations only is proposed and its security is evaluated.