def test_unaligned_data_64(self):
plaintexts = [ b"7777777" ] * 100
cipher = DES3.new(self.key_192, DES3.MODE_OPENPGP, self.iv_64)
ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
cipher = DES3.new(self.key_192, DES3.MODE_OPENPGP, self.iv_64)
self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))
def test_des3(self):
# The following test vectors have been generated with gpg v1.4.0.
# The command line used was:
# gpg -c -z 0 --cipher-algo 3DES --passphrase secret_passphrase \
# --disable-mdc --s2k-mode 0 --output ct pt
# For an explanation, see test_AES.py .
plaintext = 'ac1762037074324fb53ba3596f73656d69746556616c6c6579'
ciphertext = '9979238528357b90e2e0be549cb0b2d5999b9a4a447e5c5c7d'
key = '7ade65b460f5ea9be35f9e14aa883a2048e3824aa616c0b2'
iv='cd47e2afb8b7e4b0'
encrypted_iv='6a7eef0b58050e8b904a'
plaintext = unhexlify(plaintext)
ciphertext = unhexlify(ciphertext)
key = unhexlify(key)
iv = unhexlify(iv)
encrypted_iv = unhexlify(encrypted_iv)
cipher = DES3.new(key, DES3.MODE_OPENPGP, iv)
ct = cipher.encrypt(plaintext)
self.assertEqual(ct[:10], encrypted_iv)
self.assertEqual(ct[10:], ciphertext)
cipher = DES3.new(key, DES3.MODE_OPENPGP, encrypted_iv)
pt = cipher.decrypt(ciphertext)
self.assertEqual(pt, plaintext)
def test_loopback_64(self):
cipher = DES3.new(self.key_192, DES3.MODE_CTR, counter=self.ctr_64)
pt = get_tag_random("plaintext", 8 * 100)
ct = cipher.encrypt(pt)
cipher = DES3.new(self.key_192, DES3.MODE_CTR, counter=self.ctr_64)
pt2 = cipher.decrypt(ct)
self.assertEqual(pt, pt2)
def test_unaligned_data_64(self):
cipher = DES3.new(self.key_192, self.des3_mode, self.iv_64)
for wrong_length in xrange(1,8):
self.assertRaises(ValueError, cipher.encrypt, b("5") * wrong_length)
cipher = DES3.new(self.key_192, self.des3_mode, self.iv_64)
for wrong_length in xrange(1,8):
self.assertRaises(ValueError, cipher.decrypt, b("5") * wrong_length)
def test_loopback_64(self):
cipher = DES3.new(self.key_192, self.des3_mode, self.iv_64)
pt = get_tag_random("plaintext", 8 * 100)
ct = cipher.encrypt(pt)
cipher = DES3.new(self.key_192, self.des3_mode, self.iv_64)
pt2 = cipher.decrypt(ct)
self.assertEqual(pt, pt2)
def test_loopback_64(self):
cipher = DES3.new(self.key_192, DES3.MODE_EAX, nonce=self.nonce_96)
pt = get_tag_random("plaintext", 8 * 100)
ct = cipher.encrypt(pt)
cipher = DES3.new(self.key_192, DES3.MODE_EAX, nonce=self.nonce_96)
pt2 = cipher.decrypt(ct)
self.assertEqual(pt, pt2)
def test_loopback_64(self):
cipher = DES3.new(self.key_192, DES3.MODE_OPENPGP, self.iv_64)
pt = get_tag_random("plaintext", 8 * 100)
ct = cipher.encrypt(pt)
eiv, ct = ct[:10], ct[10:]
cipher = DES3.new(self.key_192, DES3.MODE_OPENPGP, eiv)
pt2 = cipher.decrypt(ct)
self.assertEqual(pt, pt2)
def test_unaligned_data_64(self):
plaintexts = [ b("7777777") ] * 100
cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=8)
ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=8)
self.assertEqual(b("").join(ciphertexts), cipher.encrypt(b("").join(plaintexts)))
cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=64)
ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=64)
self.assertEqual(b("").join(ciphertexts), cipher.encrypt(b("").join(plaintexts)))
def test_unaligned_data_64(self):
plaintexts = [ b"7777777" ] * 100
cipher = DES3.new(self.key_192, AES.MODE_CTR, counter=self.ctr_64)
ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
cipher = DES3.new(self.key_192, AES.MODE_CTR, counter=self.ctr_64)
self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))
cipher = DES3.new(self.key_192, AES.MODE_CTR, counter=self.ctr_64)
ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
cipher = DES3.new(self.key_192, AES.MODE_CTR, counter=self.ctr_64)
self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))
def runTest(self):
# Encrypt/Decrypt data and test output parameter
cipher = DES3.new(b'4'*8 + b'G'*8 + b'T'*8, DES3.MODE_ECB)
pt = b'5' * 16
ct = cipher.encrypt(pt)
output = bytearray(16)
res = cipher.encrypt(pt, output=output)
self.assertEqual(ct, output)
self.assertEqual(res, None)
res = cipher.decrypt(ct, output=output)
self.assertEqual(pt, output)
self.assertEqual(res, None)
import sys
if sys.version[:3] != '2.6':
output = memoryview(bytearray(16))
cipher.encrypt(pt, output=output)
self.assertEqual(ct, output)
cipher.decrypt(ct, output=output)
self.assertEqual(pt, output)
self.assertRaises(TypeError, cipher.encrypt, pt, output=b'0'*16)
self.assertRaises(TypeError, cipher.decrypt, ct, output=b'0'*16)
shorter_output = bytearray(7)
self.assertRaises(ValueError, cipher.encrypt, pt, output=shorter_output)
self.assertRaises(ValueError, cipher.decrypt, ct, output=shorter_output)
def _do_tdes_test(self, file_name):
test_vectors = load_tests(("Cryptodome", "SelfTest", "Cipher", "test_vectors", "TDES"),
file_name,
"TDES CBC KAT",
{ "count" : lambda x: int(x) } )
assert(test_vectors)
direction = None
for tv in test_vectors:
# The test vector file contains some directive lines
if isinstance(tv, basestring):
direction = tv
continue
self.description = tv.desc
if hasattr(tv, "keys"):
cipher = DES.new(tv.keys, self.des_mode, tv.iv)
else:
if tv.key1 != tv.key3:
key = tv.key1 + tv.key2 + tv.key3 # Option 3
else:
key = tv.key1 + tv.key2 # Option 2
cipher = DES3.new(key, self.des3_mode, tv.iv)
if direction == "[ENCRYPT]":
self.assertEqual(cipher.encrypt(tv.plaintext), tv.ciphertext)
elif direction == "[DECRYPT]":
self.assertEqual(cipher.decrypt(tv.ciphertext), tv.plaintext)
else:
assert False
def _do_tdes_test(self, file_name, segment_size):
test_vectors = load_tests(("Cryptodome", "SelfTest", "Cipher", "test_vectors", "TDES"),
file_name,
"AES CFB%d KAT" % segment_size,
{ "count" : lambda x: int(x) } )
assert(test_vectors)
direction = None
for tv in test_vectors:
# The test vector file contains some directive lines
if is_string(tv):
direction = tv
continue
self.description = tv.desc
if hasattr(tv, "keys"):
cipher = DES.new(tv.keys, DES.MODE_CFB, tv.iv,
segment_size=segment_size)
else:
if tv.key1 != tv.key3:
key = tv.key1 + tv.key2 + tv.key3 # Option 3
else:
key = tv.key1 + tv.key2 # Option 2
cipher = DES3.new(key, DES3.MODE_CFB, tv.iv,
segment_size=segment_size)
if direction == "[ENCRYPT]":
self.assertEqual(cipher.encrypt(tv.plaintext), tv.ciphertext)
elif direction == "[DECRYPT]":
self.assertEqual(cipher.decrypt(tv.ciphertext), tv.plaintext)
else:
assert False
def test_segment_size_64(self):
for bits in xrange(8, 65, 8):
cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64,
segment_size=bits)
for bits in 0, 7, 9, 63, 65:
self.assertRaises(ValueError, DES3.new, self.key_192, AES.MODE_CFB,
self.iv_64,
segment_size=bits)
def test_nonce_attribute(self):
# Nonce attribute is the prefix passed to Counter (DES3)
cipher = DES3.new(self.key_192, DES3.MODE_CTR, counter=self.ctr_64)
self.assertEqual(cipher.nonce, self.nonce_32)
# Nonce attribute is the prefix passed to Counter (AES)
cipher = AES.new(self.key_128, AES.MODE_CTR, counter=self.ctr_128)
self.assertEqual(cipher.nonce, self.nonce_64)
# Nonce attribute is not defined if suffix is used in Counter
counter = Counter.new(64, prefix=self.nonce_32, suffix=self.nonce_32)
cipher = AES.new(self.key_128, AES.MODE_CTR, counter=counter)
self.failIf(hasattr(cipher, "nonce"))
def encode(data, marker, passphrase=None, randfunc=None):
"""Encode a piece of binary data into PEM format.
Args:
data (byte string):
The piece of binary data to encode.
marker (string):
The marker for the PEM block (e.g. "PUBLIC KEY").
Note that there is no official master list for all allowed markers.
Still, you can refer to the OpenSSL_ source code.
passphrase (byte string):
If given, the PEM block will be encrypted. The key is derived from
the passphrase.
randfunc (callable):
Random number generation function; it accepts an integer N and returns
a byte string of random data, N bytes long. If not given, a new one is
instantiated.
Returns:
The PEM block, as a string.
.. _OpenSSL: https://github.com/openssl/openssl/blob/master/include/openssl/pem.h
"""
if randfunc is None:
randfunc = get_random_bytes
out = "-----BEGIN %s-----\n" % marker
if passphrase:
# We only support 3DES for encryption
salt = randfunc(8)
key = PBKDF1(passphrase, salt, 16, 1, MD5)
key += PBKDF1(key + passphrase, salt, 8, 1, MD5)
objenc = DES3.new(key, DES3.MODE_CBC, salt)
out += "Proc-Type: 4,ENCRYPTED\nDEK-Info: DES-EDE3-CBC,%s\n\n" %\
tostr(hexlify(salt).upper())
# Encrypt with PKCS#7 padding
data = objenc.encrypt(pad(data, objenc.block_size))
elif passphrase is not None:
raise ValueError("Empty password")
# Each BASE64 line can take up to 64 characters (=48 bytes of data)
# b2a_base64 adds a new line character!
chunks = [tostr(b2a_base64(data[i:i + 48]))
for i in range(0, len(data), 48)]
out += "".join(chunks)
out += "-----END %s-----" % marker
return out
def encode(self, data):
key_handle = DES3.new(self.uniq_id(), DES3.MODE_CBC, iv=b'\0\0\0\0\0\0\0\0')
encrypted = key_handle.encrypt(pad(data.encode('utf-8'), DES3.block_size))
return b64encode(encrypted)
def basic_decrypt(cls, key, ciphertext):
assert len(ciphertext) % 8 == 0
des3 = DES3.new(key.contents, AES.MODE_CBC, b'\0' * 8)
return des3.decrypt(bytes(ciphertext))
def encrypt(self, b):
data = self._padData(b)
return DES3.new(self._key, DES3.MODE_CBC, self._iv).encrypt(data)
def test_parity_option3(self):
before_3k = unhexlify("AAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCC")
after_3k = DES3.adjust_key_parity(before_3k)
self.assertEqual(after_3k,
unhexlify("ABABABABABABABABBABABABABABABABACDCDCDCDCDCDCDCD"))
def decrypt(self, byteString):
data = DES3.new(self._key, DES3.MODE_CBC, self._iv).decrypt(byteString)
return self._unpadData(data)
def basic_encrypt(cls, key, plaintext):
assert len(plaintext) % 8 == 0
des3 = DES3.new(key.contents, AES.MODE_CBC, b'\0' * 8)
return des3.encrypt(bytes(plaintext))
def test_block_size_64(self):
cipher = DES3.new(self.key_192, self.des3_mode, self.iv_64)
self.assertEqual(cipher.block_size, DES3.block_size)
def DES3_generation():
key = DES3.adjust_key_parity(get_random_bytes(24))
return key
def test_parity_option2(self):
before_2k = unhexlify("CABF326FA56734324FFCCABCDEFACABF")
after_2k = DES3.adjust_key_parity(before_2k)
self.assertEqual(after_2k,
unhexlify("CBBF326EA46734324FFDCBBCDFFBCBBF"))
def test_block_size_64(self):
cipher = DES3.new(self.key_192, DES3.MODE_CTR, counter=self.ctr_64)
self.assertEqual(cipher.block_size, DES3.block_size)
def test_block_size_64(self):
cipher = DES3.new(self.key_192, self.des3_mode, self.iv_64)
self.assertEqual(cipher.block_size, DES3.block_size)
def basic_decrypt(cls, key, ciphertext):
assert len(ciphertext) % 8 == 0
des3 = DES3.new(key.contents, AES.MODE_CBC, b'\0' * 8)
return des3.decrypt(bytes(ciphertext))
def decode(pem_data, passphrase=None):
"""Decode a PEM block into binary.
Args:
pem_data (string):
The PEM block.
passphrase (byte string):
If given and the PEM block is encrypted,
the key will be derived from the passphrase.
Returns:
A tuple with the binary data, the marker string, and a boolean to
indicate if decryption was performed.
Raises:
ValueError: if decoding fails, if the PEM file is encrypted and no passphrase has
been provided or if the passphrase is incorrect.
"""
# Verify Pre-Encapsulation Boundary
r = re.compile(r"\s*-----BEGIN (.*)-----\s+")
m = r.match(pem_data)
if not m:
raise ValueError("Not a valid PEM pre boundary")
marker = m.group(1)
# Verify Post-Encapsulation Boundary
r = re.compile(r"-----END (.*)-----\s*$")
m = r.search(pem_data)
if not m or m.group(1) != marker:
raise ValueError("Not a valid PEM post boundary")
# Removes spaces and slit on lines
lines = pem_data.replace(" ", '').split()
# Decrypts, if necessary
if lines[1].startswith('Proc-Type:4,ENCRYPTED'):
if not passphrase:
raise ValueError("PEM is encrypted, but no passphrase available")
DEK = lines[2].split(':')
if len(DEK) != 2 or DEK[0] != 'DEK-Info':
raise ValueError("PEM encryption format not supported.")
algo, salt = DEK[1].split(',')
salt = unhexlify(tobytes(salt))
if algo == "DES-CBC":
# This is EVP_BytesToKey in OpenSSL
key = PBKDF1(passphrase, salt, 8, 1, MD5)
objdec = DES.new(key, DES.MODE_CBC, salt)
elif algo == "DES-EDE3-CBC":
# Note that EVP_BytesToKey is note exactly the same as PBKDF1
key = PBKDF1(passphrase, salt, 16, 1, MD5)
key += PBKDF1(key + passphrase, salt, 8, 1, MD5)
objdec = DES3.new(key, DES3.MODE_CBC, salt)
elif algo == "AES-128-CBC":
key = PBKDF1(passphrase, salt[:8], 16, 1, MD5)
objdec = AES.new(key, AES.MODE_CBC, salt)
else:
raise ValueError("Unsupport PEM encryption algorithm (%s)." % algo)
lines = lines[2:]
else:
objdec = None
# Decode body
data = a2b_base64(''.join(lines[1:-1]))
enc_flag = False
if objdec:
data = unpad(objdec.decrypt(data), objdec.block_size)
enc_flag = True
return (data, marker, enc_flag)
def decode(pem_data, passphrase=None):
"""Decode a PEM block into binary.
:Parameters:
pem_data : string
The PEM block.
passphrase : byte string
If given and the PEM block is encrypted,
the key will be derived from the passphrase.
:Returns:
A tuple with the binary data, the marker string, and a boolean to
indicate if decryption was performed.
:Raises ValueError:
If decoding fails, if the PEM file is encrypted and no passphrase has
been provided or if the passphrase is incorrect.
"""
# Verify Pre-Encapsulation Boundary
r = re.compile("\s*-----BEGIN (.*)-----\s+")
m = r.match(pem_data)
if not m:
raise ValueError("Not a valid PEM pre boundary")
marker = m.group(1)
# Verify Post-Encapsulation Boundary
r = re.compile("-----END (.*)-----\s*$")
m = r.search(pem_data)
if not m or m.group(1) != marker:
raise ValueError("Not a valid PEM post boundary")
# Removes spaces and slit on lines
lines = pem_data.replace(" ", '').split()
# Decrypts, if necessary
if lines[1].startswith('Proc-Type:4,ENCRYPTED'):
if not passphrase:
raise ValueError("PEM is encrypted, but no passphrase available")
DEK = lines[2].split(':')
if len(DEK) != 2 or DEK[0] != 'DEK-Info':
raise ValueError("PEM encryption format not supported.")
algo, salt = DEK[1].split(',')
salt = unhexlify(tobytes(salt))
if algo == "DES-CBC":
# This is EVP_BytesToKey in OpenSSL
key = PBKDF1(passphrase, salt, 8, 1, MD5)
objdec = DES.new(key, DES.MODE_CBC, salt)
elif algo == "DES-EDE3-CBC":
# Note that EVP_BytesToKey is note exactly the same as PBKDF1
key = PBKDF1(passphrase, salt, 16, 1, MD5)
key += PBKDF1(key + passphrase, salt, 8, 1, MD5)
objdec = DES3.new(key, DES3.MODE_CBC, salt)
elif algo == "AES-128-CBC":
key = PBKDF1(passphrase, salt[:8], 16, 1, MD5)
objdec = AES.new(key, AES.MODE_CBC, salt)
else:
raise ValueError("Unsupport PEM encryption algorithm (%s)." % algo)
lines = lines[2:]
else:
objdec = None
# Decode body
data = a2b_base64(b(''.join(lines[1:-1])))
enc_flag = False
if objdec:
data = unpad(objdec.decrypt(data), objdec.block_size)
enc_flag = True
return (data, marker, enc_flag)
def decrypt(self,enc):
print("DES3 key ", self.key)
iv = enc[:self.block_size]
cipher = DES3.new(self.key,DES3.MODE_CBC,iv)
byte_enc = unpad(cipher.decrypt(enc[self.block_size:]),self.block_size)
return bytearray(byte_enc)
def test_block_size_64(self):
cipher = DES3.new(self.key_192, DES3.MODE_CTR, counter=self.ctr_64)
self.assertEqual(cipher.block_size, DES3.block_size)
# 3DES案例
from Cryptodome.Cipher import DES3
# 需要24个字节长度的key，一般会随机生成
# 本质上是三次des的key的串联，k1，k2，k3
# 当k1=k2=k3时，DES3降级为DES
key = b'12345678qwertyui12345678'
# 创建一个密码对象
cipher = DES3.new(key, DES3.MODE_CFB)
# 原数据
data = '我是心蓝'.encode()
# encrytion
msg = cipher.encrypt(data)
print(msg)
# 解密过程
cipher2 = DES3.new(key, DES3.MODE_CFB, iv=cipher.iv)
# 解密
res = cipher2.decrypt(msg)
print(res)
print(res.decode('utf-8'))
# 文档参考：<https://pycryptodome.readthedocs.io/en/latest/src/cipher/des3.html
from Cryptodome.Cipher import DES, DES3, ARC2, ARC4, Blowfish, AES
from Cryptodome.Random import get_random_bytes
key = b'-8B key-'
DES.new(
key, DES.MODE_OFB
) # Noncompliant: DES works with 56-bit keys allow attacks via exhaustive search
key = DES3.adjust_key_parity(get_random_bytes(24))
cipher = DES3.new(
key, DES3.MODE_CFB
) # Noncompliant: Triple DES is vulnerable to meet-in-the-middle attack
key = b'Sixteen byte key'
cipher = ARC2.new(
key,
ARC2.MODE_CFB) # Noncompliant: RC2 is vulnerable to a related-key attack
key = b'Very long and confidential key'
cipher = ARC4.new(
key
) # Noncompliant: vulnerable to several attacks (see https://en.wikipedia.org/wiki/RC4#Security)
key = b'An arbitrarily long key'
cipher = Blowfish.new(
key, Blowfish.MODE_CBC
) # Noncompliant: Blowfish use a 64-bit block size makes it vulnerable to birthday attacks
def test_parity_option2(self):
before_2k = unhexlify("CABF326FA56734324FFCCABCDEFACABF")
after_2k = DES3.adjust_key_parity(before_2k)
self.assertEqual(after_2k,
unhexlify("CBBF326EA46734324FFDCBBCDFFBCBBF"))
def des_decrypt(data, key):
cipher = DES3.new(key, DES3.MODE_ECB)
return cipher.decrypt(data)
def test_block_size_64(self):
cipher = DES3.new(self.key_192, AES.MODE_EAX, nonce=self.nonce_96)
self.assertEqual(cipher.block_size, DES3.block_size)
def encode(self, data):
k = DES3.new(self.getmac(), DES3.MODE_CBC, iv=b'\0\0\0\0\0\0\0\0')
d = k.encrypt(pad(data.encode('utf-8'), DES3.block_size))
return base64.b64encode(d)
def basic_encrypt(cls, key, plaintext):
assert len(plaintext) % 8 == 0
des3 = DES3.new(key.contents, AES.MODE_CBC, b'\0' * 8)
return des3.encrypt(bytes(plaintext))
def decode(self, data):
if not data:
return ''
k = DES3.new(self.getmac(), DES3.MODE_CBC, iv=b'\0\0\0\0\0\0\0\0')
d = unpad(k.decrypt(base64.b64decode(data)), DES3.block_size)
return d.decode('utf-8')
0x36, 0x44, 0x42, 0x19, 0x26, 0x95, 0x26, 0x4D,
0x3, 0x10, 0x15, 0x58, 0x3, 0x40, 0x5A, 0x72,
0x1E, 0xB, 0x49, 0x69, 0x4B, 0x15, 0x29, 0x6
]
K_BOX1 = [
0x56, 0x28, 0x34, 0x2E, 0x78, 0x5, 0xF, 0x5A,
0x36, 0x44, 0x42, 0x19, 0x26, 0x95, 0x26, 0x4D,
0x2D, 0x41, 0x4D, 0x1F, 0x41, 0x62, 0x15, 0x2F
]
L_KEY = bytes(bKEY[K_BOX[i]] for i in range(16)) + b'\0' * 8
L_KEY1 = bytes(bKEY[K_BOX1[i]] for i in range(24))
KEY_SUFFIX = b'\x27\x06\x58\x66'
TDesLKey = DES3.new(L_KEY, DES3.MODE_ECB)
TDesLKey1 = DES3.new(L_KEY1, DES3.MODE_ECB)
def iv_pad(d):
def rand_byte():
return os.urandom(1)
bcount = len(d) // 7
if len(d) % 7:
bcount += 1
blocks = [ d[i*7:i*7 + 7].ljust(7, b'\0') + rand_byte() for i in range(bcount) ]
return b''.join(blocks)
def iv_remove(d, flag=True):
c = b''.join(d[i*8:i*8+7] for i in range(len(d) // 8))
if flag:
def test_block_size_64(self):
cipher = DES3.new(self.key_192, AES.MODE_EAX, nonce=self.nonce_96)
self.assertEqual(cipher.block_size, DES3.block_size)
def des3_decrypt(key, filename, iv):
with open(filename, 'rb') as f:
data = f.read()
cipher_decrypt = DES3.new(key, DES3.MODE_OFB, iv)
with open(filename, 'wb') as f:
f.write(cipher_decrypt.decrypt(data))
def decode(pem_data, passphrase=None):
"""Decode a PEM block into binary.
Args:
pem_data (string):
The PEM block.
passphrase (byte string):
If given and the PEM block is encrypted,
the key will be derived from the passphrase.
Returns:
A tuple with the binary data, the marker string, and a boolean to
indicate if decryption was performed.
Raises:
ValueError: if decoding fails, if the PEM file is encrypted and no passphrase has
been provided or if the passphrase is incorrect.
"""
# Verify Pre-Encapsulation Boundary
r = re.compile(r"\s*-----BEGIN (.*)-----\s+")
m = r.match(pem_data)
if not m:
raise ValueError("Not a valid PEM pre boundary")
marker = m.group(1)
# Verify Post-Encapsulation Boundary
r = re.compile(r"-----END (.*)-----\s*$")
m = r.search(pem_data)
if not m or m.group(1) != marker:
raise ValueError("Not a valid PEM post boundary")
# Removes spaces and slit on lines
lines = pem_data.replace(" ", '').split()
# Decrypts, if necessary
if lines[1].startswith('Proc-Type:4,ENCRYPTED'):
if not passphrase:
raise ValueError("PEM is encrypted, but no passphrase available")
DEK = lines[2].split(':')
if len(DEK) != 2 or DEK[0] != 'DEK-Info':
raise ValueError("PEM encryption format not supported.")
algo, salt = DEK[1].split(',')
salt = unhexlify(tobytes(salt))
padding = True
if algo == "DES-CBC":
key = _EVP_BytesToKey(passphrase, salt, 8)
objdec = DES.new(key, DES.MODE_CBC, salt)
elif algo == "DES-EDE3-CBC":
key = _EVP_BytesToKey(passphrase, salt, 24)
objdec = DES3.new(key, DES3.MODE_CBC, salt)
elif algo == "AES-128-CBC":
key = _EVP_BytesToKey(passphrase, salt[:8], 16)
objdec = AES.new(key, AES.MODE_CBC, salt)
elif algo == "AES-192-CBC":
key = _EVP_BytesToKey(passphrase, salt[:8], 24)
objdec = AES.new(key, AES.MODE_CBC, salt)
elif algo == "AES-256-CBC":
key = _EVP_BytesToKey(passphrase, salt[:8], 32)
objdec = AES.new(key, AES.MODE_CBC, salt)
elif algo.lower() == "id-aes256-gcm":
key = _EVP_BytesToKey(passphrase, salt[:8], 32)
objdec = AES.new(key, AES.MODE_GCM, nonce=salt)
padding = False
else:
raise ValueError("Unsupport PEM encryption algorithm (%s)." % algo)
lines = lines[2:]
else:
objdec = None
# Decode body
data = a2b_base64(''.join(lines[1:-1]))
enc_flag = False
if objdec:
if padding:
data = unpad(objdec.decrypt(data), objdec.block_size)
else:
# There is no tag, so we don't use decrypt_and_verify
data = objdec.decrypt(data)
enc_flag = True
return (data, marker, enc_flag)
