Cryptographic Apparatuses And Methods For Encrypting And Decrypting Data Using Automata

A cryptographic method for encrypting unencrypted data, comprising the steps of:

• converting the unencrypted data into encrypted data by means of a key automaton (44),
• characterised by
• applying a composition of automata as the key automaton (44), said composition of automata having a set of states and a set of input signals identical to each other and being implemented as a permutation automaton without output signals, said composition of automata comprises at least one factor automaton without output signals, each of the unencrypted data and the encrypted data has a character set identical to each other, and the set of states and the set of input signals, respectively, consist of blocks obtained from all possible combinations of said character set, wherein the blocks are of a predetermined block length (b).

A cryptographic method for decrypting encrypted data, comprising the steps of:

• converting the encrypted data into unencrypted data by means of a key automaton (44),
• characterised by
• applying a composition of automata as the key automaton (44), said composition of automata having a set of states and a set of input signals identical to each other and being implemented as a permutation automaton without output signals, said composition of automata comprises at least one factor automaton without output signals, each of the unencrypted data and the encrypted data has a character set identical to each other, and the set of states and the set of input signals, respectively, consist of blocks obtained from all possible combinations of said character set, wherein the blocks are of a predetermined block length (b).