def _makeRelayCrypto(self, secret_input):
'''Derive shared key material using HKDF from secret_input.
:returns: **oppy.crypto.relaycrypto.RelayCrypto** initialized with
shared key data
'''
prk = hkdf.hkdf_extract(salt=T_KEY, input_key_material=secret_input,
hash=hashlib.sha256)
km = hkdf.hkdf_expand(pseudo_random_key=prk, info=M_EXPAND,
length=72, hash=hashlib.sha256)
df = km[: DIGEST_LEN]
db = km[DIGEST_LEN : DIGEST_LEN * 2]
kf = km[DIGEST_LEN * 2 : DIGEST_LEN * 2 + KEY_LEN]
kb = km[DIGEST_LEN * 2 + KEY_LEN : DIGEST_LEN * 2 + KEY_LEN * 2]
f_digest = hashlib.sha1(df)
b_digest = hashlib.sha1(db)
f_cipher = util.makeAES128CTRCipher(kf)
b_cipher = util.makeAES128CTRCipher(kb)
return RelayCrypto(forward_digest=f_digest,
backward_digest=b_digest,
forward_cipher=f_cipher,
backward_cipher=b_cipher)
def _makeRelayCrypto(self, secret_input):
'''Derive shared key material using HKDF from secret_input.
:returns: **oppy.crypto.relaycrypto.RelayCrypto** initialized with
shared key data
'''
prk = hkdf.hkdf_extract(salt=T_KEY,
input_key_material=secret_input,
hash=hashlib.sha256)
km = hkdf.hkdf_expand(pseudo_random_key=prk,
info=M_EXPAND,
length=72,
hash=hashlib.sha256)
df = km[:DIGEST_LEN]
db = km[DIGEST_LEN:DIGEST_LEN * 2]
kf = km[DIGEST_LEN * 2:DIGEST_LEN * 2 + KEY_LEN]
kb = km[DIGEST_LEN * 2 + KEY_LEN:DIGEST_LEN * 2 + KEY_LEN * 2]
f_digest = hashlib.sha1(df)
b_digest = hashlib.sha1(db)
f_cipher = util.makeAES128CTRCipher(kf)
b_cipher = util.makeAES128CTRCipher(kb)
return RelayCrypto(forward_digest=f_digest,
backward_digest=b_digest,
forward_cipher=f_cipher,
backward_cipher=b_cipher)
def test_makeAES123CTRCipher_iv(self, mock_aes, mock_counter):
mock_counter.return_value = 'ctr'
mock_aes.return_value = 'ret'
ret = util.makeAES128CTRCipher('key', 'iv')
mock_counter.assert_called_once_with(128, initial_value='iv')
mock_aes.assert_called_once_with('key', AES.MODE_CTR, counter='ctr')
self.assertEqual(ret, 'ret')
def test_makeAES123CTRCipher_iv(self, mock_aes, mock_counter):
mock_counter.return_value = 'ctr'
mock_aes.return_value = 'ret'
ret = util.makeAES128CTRCipher('key', 'iv')
mock_counter.assert_called_once_with(128, initial_value='iv')
mock_aes.assert_called_once_with('key', AES.MODE_CTR, counter='ctr')
self.assertEqual(ret, 'ret')
