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 crypt(_cfgUpgSecPls, flag):
#gen key
passphrase = b'h@k8807H$Z5998'
passphrase = passphrase.ljust(31, b'\x00')
salt = b'HangZhou'
key = PBKDF1(passphrase, salt, 16, 2, MD5)
key += PBKDF1(key + passphrase, salt, 16, 2, MD5)
cipher = AES.new(key, AES.MODE_ECB)
_cfgUpgSecPls = pad(_cfgUpgSecPls, 16)
if flag == 'd':
#dec _cfg
dec_cfgUpgSecPls = cipher.decrypt(_cfgUpgSecPls)
return dec_cfgUpgSecPls
else:
#enc _cfg
enc_cfgUpgSecPls = cipher.encrypt(_cfgUpgSecPls)
return enc_cfgUpgSecPls
def decrypt(data, passphrase):
"""Decrypt a piece of data using a passphrase and *PBES1*.
The algorithm to use is automatically detected.
:Parameters:
data : byte string
The piece of data to decrypt.
passphrase : byte string
The passphrase to use for decrypting the data.
:Returns:
The decrypted data, as a binary string.
"""
enc_private_key_info = DerSequence().decode(data)
encrypted_algorithm = DerSequence().decode(enc_private_key_info[0])
encrypted_data = DerOctetString().decode(
enc_private_key_info[1]).payload
pbe_oid = DerObjectId().decode(encrypted_algorithm[0]).value
cipher_params = {}
if pbe_oid == _OID_PBE_WITH_MD5_AND_DES_CBC:
# PBE_MD5_DES_CBC
hashmod = MD5
ciphermod = DES
elif pbe_oid == _OID_PBE_WITH_MD5_AND_RC2_CBC:
# PBE_MD5_RC2_CBC
hashmod = MD5
ciphermod = ARC2
cipher_params['effective_keylen'] = 64
elif pbe_oid == _OID_PBE_WITH_SHA1_AND_DES_CBC:
# PBE_SHA1_DES_CBC
hashmod = SHA1
ciphermod = DES
elif pbe_oid == _OID_PBE_WITH_SHA1_AND_RC2_CBC:
# PBE_SHA1_RC2_CBC
hashmod = SHA1
ciphermod = ARC2
cipher_params['effective_keylen'] = 64
else:
raise PbesError("Unknown OID for PBES1")
pbe_params = DerSequence().decode(encrypted_algorithm[1],
nr_elements=2)
salt = DerOctetString().decode(pbe_params[0]).payload
iterations = pbe_params[1]
key_iv = PBKDF1(passphrase, salt, 16, iterations, hashmod)
key, iv = key_iv[:8], key_iv[8:]
cipher = ciphermod.new(key, ciphermod.MODE_CBC, iv, **cipher_params)
pt = cipher.decrypt(encrypted_data)
return unpad(pt, cipher.block_size)
def test1(self):
v = self._testData[0]
res = PBKDF1(v[0], t2b(v[1]), v[2], v[3], SHA1)
self.assertEqual(res, t2b(v[4]))
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)
