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support pyelliptic's updated HMAC algorithm

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This commit is contained in:
Jonathan Warren 2014-07-29 03:35:23 -04:00
parent bb48f44968
commit fbfbbf68b5
1 changed files with 10 additions and 1 deletions
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11
src/pyelliptic/ecc.py
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@ -437,8 +437,10 @@ class ECC:
iv = OpenSSL.rand(OpenSSL.get_cipher(ciphername).get_blocksize()) iv = OpenSSL.rand(OpenSSL.get_cipher(ciphername).get_blocksize())
ctx = Cipher(key_e, iv, 1, ciphername) ctx = Cipher(key_e, iv, 1, ciphername)
ciphertext = ctx.ciphering(data) ciphertext = ctx.ciphering(data)
#ciphertext = iv + pubkey + ctx.ciphering(data) # We will switch to this line after an upgrade period
mac = hmac_sha256(key_m, ciphertext) mac = hmac_sha256(key_m, ciphertext)
return iv + pubkey + ciphertext + mac return iv + pubkey + ciphertext + mac
#return ciphertext + mac # We will switch to this line after an upgrade period.
def decrypt(self, data, ciphername='aes-256-cbc'): def decrypt(self, data, ciphername='aes-256-cbc'):
""" """
@ -454,7 +456,14 @@ class ECC:
mac = data[i:] mac = data[i:]
key = sha512(self.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest() key = sha512(self.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest()
key_e, key_m = key[:32], key[32:] key_e, key_m = key[:32], key[32:]
"""
pyelliptic was changed slightly so that the hmac covers the
iv and pubkey. So let's have an upgrade period where we support
both the old and the new hmac'ing algorithms.
https://github.com/yann2192/pyelliptic/issues/17
"""
if hmac_sha256(key_m, ciphertext) != mac: if hmac_sha256(key_m, ciphertext) != mac:
raise RuntimeError("Fail to verify data") if hmac_sha256(key_m, data[:len(data) - 32]) != mac:
raise RuntimeError("Fail to verify data")
ctx = Cipher(key_e, iv, 0, ciphername) ctx = Cipher(key_e, iv, 0, ciphername)
return ctx.ciphering(ciphertext) return ctx.ciphering(ciphertext)