Cipher communication method and apparatus for the same

An encryption apparatus for seamless cipher communication with another encryption apparatus, comprising:

• an interface unit configured to receive a second encryption key from another encryption apparatus connected to the encryption apparatus over a network while performing a cipher communication using a first encryption key;
• a storage management unit configured to store encryption key input information on the first and second encryption keys in a static region and store the stored encryption key input information in a dynamic region;
• and
• a controller configured to select any one of the first and second encryption keys by comparing the copied encryption key input information on the first encryption key, the copied encryption key input information on the second encryption key, and current time information, generate encryption key position information and encryption key selection information on the selected encryption key, and transmit a cipher text and the encryption key selection information to the other encryption apparatus such that the other encryption apparatus acquires an encryption key to decrypt the cipher text.