Abstract:
An apparatus and method for converting a random binary sequence into a random integer is provided. The present invention converts a random binary sequence into a random integer, and determines whether the corresponding random integer falls within a preset integer interval. Further, if it is determined that the random integer generated from the random binary sequence does not fall within the preset integer interval, the present invention repeatedly updates a random binary sequence until a random integer falling within the corresponding integer interval is obtained, thus outputting uniformly distributed random integers which fall within the preset integer interval.
Abstract:
An apparatus and method for providing a Feistel-based variable length block cipher, which are configured to when plaintext having a certain bit length is encrypted, generate ciphertext having the same bit length as plaintext, and to decrypt ciphertext into plaintext having the same bit length. The apparatus includes an encryption/decryption key generation unit for generating a number of encryption/decryption keys corresponding to a preset number of rounds, based on a secret key, the length of the secret key, the length of plaintext, and a round constant; an encryption/decryption tweak generation unit for generating an encryption/decryption tweak based on a tweak, a length of tweak, and the length of plaintext; and a ciphertext output unit for outputting ciphertext having length identical to that of plaintext, based on plaintext, the length of the plaintext, the length of the secret key, the encryption/decryption keys, and the encryption/decryption tweak.
Abstract:
A variable-length block cipher apparatus and method capable of format preserving encryption are provided. An encryption device for a variable-length block cipher apparatus includes an encryption key generation unit configured to generate encryption round keys eRK0, eRK1, . . . , eRKNr using a secret key and the number of rounds Nr, and a ciphertext output unit configured to output ciphertext having a length identical to that of plaintext using the plaintext and the encryption round keys. 7. A decryption device for a variable-length block cipher apparatus includes a decryption key generation unit configured to generate decryption round keys dRK0, dRK1, . . . , dRKNr using a secret key and a number of rounds Nr, and a plaintext restoration unit configured to restore ciphertext into plaintext having a length identical to that of the ciphertext using the ciphertext and the decryption round keys.