1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
# -*- coding: utf-8 -*-
'''
Utilities to make secret box encryption simple
'''
# Import libnacl
import libnacl
import libnacl.utils
import libnacl.base
class AEAD(libnacl.base.BaseKey):
'''
Manage AEAD encryption using the IETF ChaCha20-Poly1305(default) or AES-GCM algorithm
'''
def __init__(self, key=None):
if key is None:
key = libnacl.utils.aead_key()
if len(key) != libnacl.crypto_aead_chacha20poly1305_ietf_KEYBYTES: # same size for both
raise ValueError('Invalid key')
self.sk = key
self.usingAES = False
self.usingXCHACHA = False
super().__init__()
def useAESGCM(self):
self.usingAES = True
return self
def useXCHACHA(self):
self.usingXCHACHA = True
return self
def encrypt(self, msg, aad, nonce=None, pack_nonce_aad=True):
'''
Encrypt the given message. If a nonce is not given it will be
generated via the rand_nonce function
'''
if nonce is None:
if self.usingXCHACHA:
nonce = libnacl.utils.rand_aead_xchacha_nonce()
else:
nonce = libnacl.utils.rand_aead_nonce()
if self.usingXCHACHA:
if len(nonce) != libnacl.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES:
raise ValueError('Invalid nonce')
else:
if len(nonce) != libnacl.crypto_aead_aes256gcm_NPUBBYTES:
raise ValueError('Invalid nonce')
if self.usingXCHACHA:
ctxt = libnacl.crypto_aead_xchacha20poly1305_ietf_encrypt(msg, aad, nonce, self.sk)
elif self.usingAES:
ctxt = libnacl.crypto_aead_aes256gcm_encrypt(msg, aad, nonce, self.sk)
else:
ctxt = libnacl.crypto_aead_chacha20poly1305_ietf_encrypt(msg, aad, nonce, self.sk)
if pack_nonce_aad:
return aad + nonce + ctxt
else:
return aad, nonce, ctxt
def decrypt(self, ctxt, aadLen):
'''
Decrypt the given message, if no nonce or aad are given they will be
extracted from the message
'''
aad = ctxt[:aadLen]
if self.usingXCHACHA:
nonce = ctxt[aadLen:aadLen+libnacl.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES]
ctxt = ctxt[aadLen+libnacl.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES:]
if len(nonce) != libnacl.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES:
raise ValueError('Invalid nonce')
else:
nonce = ctxt[aadLen:aadLen+libnacl.crypto_aead_aes256gcm_NPUBBYTES]
ctxt = ctxt[aadLen+libnacl.crypto_aead_aes256gcm_NPUBBYTES:]
if len(nonce) != libnacl.crypto_aead_aes256gcm_NPUBBYTES:
raise ValueError('Invalid nonce')
if self.usingXCHACHA:
return libnacl.crypto_aead_xchacha20poly1305_ietf_decrypt(ctxt, aad, nonce, self.sk)
if self.usingAES:
return libnacl.crypto_aead_aes256gcm_decrypt(ctxt, aad, nonce, self.sk)
return libnacl.crypto_aead_chacha20poly1305_ietf_decrypt(ctxt, aad, nonce, self.sk)
def decrypt_unpacked(self, aad, nonce, ctxt):
'''
Decrypt the given message, if no nonce or aad are given they will be
extracted from the message
'''
if len(nonce) != libnacl.crypto_aead_aes256gcm_NPUBBYTES:
raise ValueError('Invalid nonce')
if self.usingAES:
return libnacl.crypto_aead_aes256gcm_decrypt(ctxt, aad, nonce, self.sk)
return libnacl.crypto_aead_chacha20poly1305_ietf_decrypt(ctxt, aad, nonce, self.sk)
class AEAD_AESGCM(AEAD):
def __init__(self, key=None):
super().__init__(key)
self.useAESGCM()
class AEAD_XCHACHA(AEAD):
def __init__(self, key=None):
super().__init__(key)
self.useXCHACHA()
class AEAD_CHACHA(AEAD):
def __init__(self, key=None):
super().__init__(key)
|
