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import lilliput_ae_1
import lilliput_ae_2
N_BYTES = 15
def _getParameters(mode=1, key_length=128) :
rounds = {
128: 32,
192: 36,
256: 42
}
tweak_lengths = {
1: 192,
2: 128
}
return tweak_lengths[mode], rounds[key_length]
############################################
def _checkInputs(key, nonce):
valid_key_lengths = (128, 192, 256)
if len(key)*8 not in valid_key_lengths:
raise ValueError('invalid key size: {} not in {}'.format(len(key)*8, valid_key_lengths))
if len(nonce) != N_BYTES:
raise ValueError('nonce must be {}-byte long'.format(N_BYTES))
def mainEnc(plaintext, adata, key, nonce, mode):
_checkInputs(key, nonce)
tweak_bits, rounds = _getParameters(mode, len(key)*8)
A = adata
M = plaintext
N = nonce
if(mode == 1) :
return lilliput_ae_1.OCB3Enc(A, M, N, key, tweak_bits, rounds)
if(mode == 2) :
return lilliput_ae_2.SCT2Enc(A, M, N, key, tweak_bits, rounds)
def mainDec(ciphertext, tag, adata, key, nonce, mode):
_checkInputs(key, nonce)
tweak_bits, rounds = _getParameters(mode, len(key)*8)
A = adata
C = ciphertext
N = nonce
tag = list(tag)
if(mode == 1) :
return lilliput_ae_1.OCB3Dec(A, C, N, tag, key, tweak_bits, rounds)
if(mode == 2) :
return lilliput_ae_2.SCT2Dec(A, C, N, tag, key, tweak_bits, rounds)
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