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1# Author: Trevor Perrin
2# See the LICENSE file for legal information regarding use of this file.
3
4"""Factory functions for symmetric cryptography."""
5
6import os
7
8from tlslite.utils import python_aes
9from tlslite.utils import python_rc4
10
11from tlslite.utils import cryptomath
12
13tripleDESPresent = False
14
15if cryptomath.m2cryptoLoaded:
16    from tlslite.utils import openssl_aes
17    from tlslite.utils import openssl_rc4
18    from tlslite.utils import openssl_tripledes
19    tripleDESPresent = True
20
21if cryptomath.pycryptoLoaded:
22    from tlslite.utils import pycrypto_aes
23    from tlslite.utils import pycrypto_rc4
24    from tlslite.utils import pycrypto_tripledes
25    tripleDESPresent = True
26
27# **************************************************************************
28# Factory Functions for AES
29# **************************************************************************
30
31def createAES(key, IV, implList=None):
32    """Create a new AES object.
33
34    @type key: str
35    @param key: A 16, 24, or 32 byte string.
36
37    @type IV: str
38    @param IV: A 16 byte string
39
40    @rtype: L{tlslite.utils.AES}
41    @return: An AES object.
42    """
43    if implList == None:
44        implList = ["openssl", "pycrypto", "python"]
45
46    for impl in implList:
47        if impl == "openssl" and cryptomath.m2cryptoLoaded:
48            return openssl_aes.new(key, 2, IV)
49        elif impl == "pycrypto" and cryptomath.pycryptoLoaded:
50            return pycrypto_aes.new(key, 2, IV)
51        elif impl == "python":
52            return python_aes.new(key, 2, IV)
53    raise NotImplementedError()
54
55def createRC4(key, IV, implList=None):
56    """Create a new RC4 object.
57
58    @type key: str
59    @param key: A 16 to 32 byte string.
60
61    @type IV: object
62    @param IV: Ignored, whatever it is.
63
64    @rtype: L{tlslite.utils.RC4}
65    @return: An RC4 object.
66    """
67    if implList == None:
68        implList = ["openssl", "pycrypto", "python"]
69
70    if len(IV) != 0:
71        raise AssertionError()
72    for impl in implList:
73        if impl == "openssl" and cryptomath.m2cryptoLoaded:
74            return openssl_rc4.new(key)
75        elif impl == "pycrypto" and cryptomath.pycryptoLoaded:
76            return pycrypto_rc4.new(key)
77        elif impl == "python":
78            return python_rc4.new(key)
79    raise NotImplementedError()
80
81#Create a new TripleDES instance
82def createTripleDES(key, IV, implList=None):
83    """Create a new 3DES object.
84
85    @type key: str
86    @param key: A 24 byte string.
87
88    @type IV: str
89    @param IV: An 8 byte string
90
91    @rtype: L{tlslite.utils.TripleDES}
92    @return: A 3DES object.
93    """
94    if implList == None:
95        implList = ["openssl", "pycrypto"]
96
97    for impl in implList:
98        if impl == "openssl" and cryptomath.m2cryptoLoaded:
99            return openssl_tripledes.new(key, 2, IV)
100        elif impl == "pycrypto" and cryptomath.pycryptoLoaded:
101            return pycrypto_tripledes.new(key, 2, IV)
102    raise NotImplementedError()