Symmetric key encryption algorithm complements the way for multilingual text string encryption

摘要

It is done by a feature to include the method of the present invention, when it ciphers the multi-lingual text string like the Korean, Japanese handled in the computer with symmetric key encryption algorithm, it provides the method for preventing from not being able to display the ciphertext on computer terminal console as it deviates from character code domain, it also provides the method which the length of ciphertext is maintained identically with the original plaintext. As especially, it fixes several bits of the multi- lingual character code defined as double-byte, and it encrypts the rest of bits when it ciphers the character string which is handled in the computer with the procedure of the several steps based on the mathematical operator. Then, the character code domain of the ciphertext is curbed in the domain of the fixed bits.