ENCRYPTION METHOD FOR HIGHEST SECURITY APPLICATIONS

A method for encrypting a message M of I M -bit length, comprises the steps of a) providing a first random bit sequence of I R -bit length, I R ‰¥ I M ; b) subdividing said message M into unitary message strings of / s -bits, wherein / s ‰ I M ; c) for each unitary message string, executing an XOR-operation of said unitary message string with Is bits of said first random bit sequence for generating an encrypted unitary string; and d) assembling said encrypted unitary strings into a cipher text. According to the invention the assembly of the cipher text is such, that the positions of said encrypted unitary strings in said cipher text are randomly permuted with respect to the positions of the corresponding unitary message strings in said message. In other words, the step of assembling said encrypted unitary strings into a cipher text comprises the step of randomly permuting the positions of said encrypted unitary strings in said cipher text with respect to the positions of the corresponding unitary message strings in said message.