Apparatus and method for encryption

An encryption apparatus comprising:

• at least one processor configured to implement:
• a key table generator configured to generate at least one encryption key table from random values obtained from a seed value and generate at least one decryption key table from the at least one encryption key table;
• an algorithm generator configured to generate an encryption algorithm having a first Misty structure that has a first round function to which the at least one encryption key table is applied and a decryption algorithm having a second Misty structure that has a second round function to which the at least one decryption key table is applied;
• an encryptor configured to encrypt plaintext data with the encryption algorithm;
• and
• a decryptor configured to decrypt the encrypted plaintext data with the decryption algorithm,
• wherein each of the at least one encryption key table and the at least one decryption key table is a lookup table,
• wherein the key table generator determines a size of the random values based on an amount of memory available for encryption, and
• wherein the algorithm generator determines a number of branches of the first Misty structure based on a size of a unit input and a size of the random values.