I'm doing AES 256 encrypt/decrypt and I can't figure out why I'm getting this error.
Key : fce4aa4dcf0d2b27fe4ffdafa602c81d1930c410f48ada5c763d4c4052a939eb
IV : c75271d593ca86ca785e3bb25e8d02cb
Traceback (most recent call last):
File "C:\Users\xx\Desktop\pycrypto.py", line 25, in <module>
print(a.encrypt(codecs.decode("This bloody encryption engine won't work !", 'c75271d593ca86ca785e3bb25e8d02cb', 'hex_codec')))
LookupError: unknown encoding: c75271d593ca86ca785e3bb25e8d02cb
import base64
from Crypto.Cipher import AES
from Crypto import Random
import codecs
BS = 16
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
unpad = lambda s : s[:-ord(s[len(s)-1:])]
class AESCipher:
def __init__( self, key ):
self.key = key
def encrypt( self, raw, iv ):
raw = pad(raw)
cipher = AES.new( self.key, AES.MODE_CBC, iv )
return base64.b64encode( cipher.encrypt( raw ) )
def decrypt( self, enc, iv ):
enc = base64.b64decode(enc)
cipher = AES.new(self.key, AES.MODE_CBC, iv )
return unpad(cipher.decrypt( enc ))
a = AESCipher(codecs.decode('fce4aa4dcf0d2b27fe4ffdafa602c81d1930c410f48ada5c763d4c4052a939eb', 'hex_codec'))
print(a.encrypt(codecs.decode("This bloody encryption engine won't work !", 'c75271d593ca86ca785e3bb25e8d02cb', 'hex_codec')))
b = AESCipher(codecs.decode('fce4aa4dcf0d2b27fe4ffdafa602c81d1930c410f48ada5c763d4c4052a939eb', 'hex_codec'))
print(b.decrypt(codecs.decode('44FsQIcqM412+YXZBwwoQSCz2uB9QPQMXJ410Xpw1f/M5RTRS7N6yfziAGq/Fd/E', 'c75271d593ca86ca785e3bb25e8d02cb', 'hex_codec')))
From the docs, codecs.decode() takes the following arguments:
codecs.decode(obj, encoding='utf-8', errors='strict')
In your case, you're passing c75271d593ca86ca785e3bb25e8d02cb as the encoding, hence the error.
I'm trying to use TCP sockets to send an encrypted message from one computer to another. The server encrypts the string, sends it to the client, and the client decrypts the string and prints the raw version. However, I keep getting this error on the client:
ValueError: IV must be 16 bytes long
The server code is:
import socket, hashlib, base64
from Crypto.Cipher import AES
from Crypto import Random
BLOCK_SIZE = 16
pad = lambda s: s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * chr(BLOCK_SIZE - len(s) % BLOCK_SIZE)
unpad = lambda s: s[:-ord(s[len(s) - 1:])]
password = "sdfsdfJDFJDSF8sd9fs"
def encrypt(raw, password):
private_key = hashlib.sha256(password.encode("utf-8")).digest()
raw = pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(private_key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw))
def decrypt(enc, password):
private_key = hashlib.sha256(password.encode("utf-8")).digest()
enc = base64.b64decode(enc)
iv = enc[:16]
cipher = AES.new(private_key, AES.MODE_CBC, iv)
return unpad(cipher.decrypt(enc[16:]))
s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(("192.168.1.150", 443))
s.listen(5)
print("\n\nListening...\n\n")
conn, addr = s.accept()
print("\n\nConnection from\n\n")
message="hello world"
data=encrypt(message, password)
s.send(data)
The client code is:
import socket, base64, hashlib
from Crypto.Cipher import AES
from Crypto import Random
BLOCK_SIZE = 16
pad = lambda s: s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * chr(BLOCK_SIZE - len(s) % BLOCK_SIZE)
unpad = lambda s: s[:-ord(s[len(s) - 1:])]
password = "sdfsdfJDFJDSF8sd9fs"
def encrypt(raw, password):
private_key = hashlib.sha256(password.encode("utf-8")).digest()
raw = pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(private_key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw))
def decrypt(enc, password):
private_key = hashlib.sha256(password.encode("utf-8")).digest()
enc = base64.b64decode(enc)
iv = enc[:16]
cipher = AES.new(private_key, AES.MODE_CBC, iv)
return unpad(cipher.decrypt(enc[16:]))
s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("192.168.1.150", 443))
data=s.recv(1024)
shellcode_raw=decrypt(data, password)
print(shellcode_raw)
I figured it out. I believe it was an error in the conversion of bytes to string, but I'm not sure. I also increased the number of bytes in the s.recv(1024) function to s.recv(4096) Here is the code.
The server code:
import base64
import hashlib
import socket
from Crypto import Random
from Crypto.Cipher import AES
class AESCipher(object):
def __init__(self, key):
self.bs = AES.block_size
self.key = hashlib.sha256(key.encode()).digest()
def encrypt(self, raw):
raw = self._pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw.encode()))
def decrypt(self, enc):
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return self._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8')
def _pad(self, s):
return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)
#staticmethod
def _unpad(s):
return s[:-ord(s[len(s)-1:])]
string="super secure"
password="djknBDS89dHFS(*HFSD())"
enc_string=str(AESCipher(password).encrypt(string))
enc_string_2=AESCipher(password).encrypt(string)
dec_string=str(AESCipher(password).decrypt(enc_string_2))
print("This is the password " + password)
print("Decrypted string: " + string)
print("Encrypted string: " + enc_string)
print("Decrypted string (v2): " + str(dec_string))
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(('192.168.1.150', 4444))
sock.listen(5)
print("Listening for connections...")
conn, addr = sock.accept()
conn.send(enc_string_2)
conn.close()
The client code:
import socket
import base64
from Crypto import Random
from Crypto.Cipher import AES
import hashlib
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(('192.168.1.150', 4444))
class AESCipher(object):
def __init__(self, key):
self.bs = AES.block_size
self.key = hashlib.sha256(key.encode()).digest()
def encrypt(self, raw):
raw = self._pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw.encode()))
def decrypt(self, enc):
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return self._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8')
def _pad(self, s):
return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)
#staticmethod
def _unpad(s):
return s[:-ord(s[len(s)-1:])]
password="djknBDS89dHFS(*HFSD())"
data=sock.recv(4096)
decoded=AESCipher(password).decrypt(data.decode('utf-8'))
print(str(decoded))
sock.close()
I'm trying to realize hybrid cryptosystem with pycryptodome.
from Crypto.PublicKey import RSA
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
from Crypto.Random.random import getrandbits
from Crypto.Cipher import PKCS1_v1_5
from Crypto.Hash import SHA
from Crypto import Random
import base64
import hashlib
import os
def main():
setup()
data = b'12 43 42 46 af'
key, data = send_data_to_dron(data)
receive_data(key, data)
class AESCipher:
def __init__(self, key):
self.key = key
def pad(self, s):
return s + b"\0" * (AES.block_size - len(s) % AES.block_size)
def encrypt(self, message, key, key_size=256):
message = self.pad(message)
iv = Random.new().read(AES.block_size)
cipher = AES.new(key, AES.MODE_CBC, iv)
return iv + cipher.encrypt(message)
def decrypt(self, ciphertext, key):
iv = ciphertext[:AES.block_size]
print(len(key))
cipher = AES.new(key, AES.MODE_CBC, iv)
plaintext = cipher.decrypt(ciphertext[AES.block_size:])
return plaintext.rstrip(b"\0")
def receive_data(key, data):
private_key = RSA.import_key(open("./keys/private1.pem").read())
dsize = SHA.digest_size
sentinel = Random.new().read(15+dsize)
cipher = PKCS1_v1_5.new(private_key)
aes_key = cipher.decrypt(key, sentinel)
print("dec AES key:", aes_key)
cipher = AESCipher(aes_key)
decrypted = cipher.decrypt(data, key)
return decrypted
def send_data_to_dron(data):
key = os.urandom(16)
print("gen AES key:", key)
print(len(key))
cipher = AESCipher(key)
ciphertext = cipher.encrypt(data, key)
rsa_public1 = RSA.import_key(open("./keys/public1.pem").read())
cipher = PKCS1_v1_5.new(rsa_public1)
ecnrypted_aes_key = cipher.encrypt(key)
return ecnrypted_aes_key, ciphertext
def setup():
key1 = RSA.generate(2048)
private_key1 = key1.export_key()
fileout = open("./keys/private1.pem", mode="wb+")
fileout.write(private_key1)
public_key1 = key1.publickey().export_key()
file_out = open("./keys/public1.pem", "wb+")
file_out.write(public_key1)
key2 = RSA.generate(2048)
private_key2 = key2.export_key()
fileout = open("./keys/private2.pem", mode="wb+")
fileout.write(private_key2)
public_key2 = key2.publickey().export_key()
file_out = open("./keys/public2.pem", "wb+")
file_out.write(public_key2)
send_private("./keys/private1.pem", to='dron')
send_private("./keys/private2.pem", to='operator')
send_public("./keys/public1.pem", to='dron')
send_public("./keys/public2.pem", to='operator')
def send_private(keyfile_path, to='dron'):
pass
def send_public(keyfile_path, to='dron'):
pass
if __name__ == '__main__':
main()
Have such output:
gen AES key: b'A\xef\xc1\xa8\xa1\rf\xb3\xd1\x95\xe4L\xc1.\x16\xa9'<br>
16 (length of generated key)<br>
dec AES key: b'A\xef\xc1\xa8\xa1\rf\xb3\xd1\x95\xe4L\xc1.\x16\xa9'<br>
256 (lenght of decrypted key)<br>
<i>Long traceback</i><br>
ValueError: Incorrect AES key length (256 bytes)<br>
I may specialize padding for RSA encrypting, but I don't know how to do it.
Solved by my own.
def receive_data(key, data):
...
decrypted = cipher.decrypt(data, aes_key)#used variable ket instead of aes key
...
But i think i should leave it here for future users)
I'm trying to build two functions using PyCrypto that accept two parameters: the message and the key, and then encrypt/decrypt the message.
I found several links on the web to help me out, but each one of them has flaws:
This one at codekoala uses os.urandom, which is discouraged by PyCrypto.
Moreover, the key I give to the function is not guaranteed to have the exact length expected. What can I do to make that happen?
Also, there are several modes, which one is recommended? I don't know what to use :/
Finally, what exactly is the IV? Can I provide a different IV for encrypting and decrypting, or will this return in a different result?
Here is my implementation, and it works for me with some fixes. It enhances the alignment of the key and secret phrase with 32 bytes and IV to 16 bytes:
import base64
import hashlib
from Crypto import Random
from Crypto.Cipher import AES
class AESCipher(object):
def __init__(self, key):
self.bs = AES.block_size
self.key = hashlib.sha256(key.encode()).digest()
def encrypt(self, raw):
raw = self._pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw.encode()))
def decrypt(self, enc):
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return self._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8')
def _pad(self, s):
return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)
#staticmethod
def _unpad(s):
return s[:-ord(s[len(s)-1:])]
You may need the following two functions: pad- to pad (when doing encryption) and unpad- to unpad (when doing decryption) when the length of input is not a multiple of BLOCK_SIZE.
BS = 16
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
unpad = lambda s : s[:-ord(s[len(s)-1:])]
So you're asking the length of key? You can use the MD5 hash of the key rather than use it directly.
More, according to my little experience of using PyCrypto, the IV is used to mix up the output of a encryption when input is same, so the IV is chosen as a random string, and use it as part of the encryption output, and then use it to decrypt the message.
And here's my implementation:
import base64
from Crypto.Cipher import AES
from Crypto import Random
class AESCipher:
def __init__( self, key ):
self.key = key
def encrypt( self, raw ):
raw = pad(raw)
iv = Random.new().read( AES.block_size )
cipher = AES.new( self.key, AES.MODE_CBC, iv )
return base64.b64encode( iv + cipher.encrypt( raw ) )
def decrypt( self, enc ):
enc = base64.b64decode(enc)
iv = enc[:16]
cipher = AES.new(self.key, AES.MODE_CBC, iv )
return unpad(cipher.decrypt( enc[16:] ))
Let me address your question about "modes." AES-256 is a kind of block cipher. It takes as input a 32-byte key and a 16-byte string, called the block and outputs a block. We use AES in a mode of operation in order to encrypt. The solutions above suggest using CBC, which is one example. Another is called CTR, and it's somewhat easier to use:
from Crypto.Cipher import AES
from Crypto.Util import Counter
from Crypto import Random
# AES supports multiple key sizes: 16 (AES128), 24 (AES192), or 32 (AES256).
key_bytes = 32
# Takes as input a 32-byte key and an arbitrary-length plaintext and returns a
# pair (iv, ciphtertext). "iv" stands for initialization vector.
def encrypt(key, plaintext):
assert len(key) == key_bytes
# Choose a random, 16-byte IV.
iv = Random.new().read(AES.block_size)
# Convert the IV to a Python integer.
iv_int = int(binascii.hexlify(iv), 16)
# Create a new Counter object with IV = iv_int.
ctr = Counter.new(AES.block_size * 8, initial_value=iv_int)
# Create AES-CTR cipher.
aes = AES.new(key, AES.MODE_CTR, counter=ctr)
# Encrypt and return IV and ciphertext.
ciphertext = aes.encrypt(plaintext)
return (iv, ciphertext)
# Takes as input a 32-byte key, a 16-byte IV, and a ciphertext, and outputs the
# corresponding plaintext.
def decrypt(key, iv, ciphertext):
assert len(key) == key_bytes
# Initialize counter for decryption. iv should be the same as the output of
# encrypt().
iv_int = int(iv.encode('hex'), 16)
ctr = Counter.new(AES.block_size * 8, initial_value=iv_int)
# Create AES-CTR cipher.
aes = AES.new(key, AES.MODE_CTR, counter=ctr)
# Decrypt and return the plaintext.
plaintext = aes.decrypt(ciphertext)
return plaintext
(iv, ciphertext) = encrypt(key, 'hella')
print decrypt(key, iv, ciphertext)
This is often referred to as AES-CTR. I would advise caution in using AES-CBC with PyCrypto. The reason is that it requires you to specify the padding scheme, as exemplified by the other solutions given. In general, if you're not very careful about the padding, there are attacks that completely break encryption!
Now, it's important to note that the key must be a random, 32-byte string; a password does not suffice. Normally, the key is generated like so:
# Nominal way to generate a fresh key. This calls the system's random number
# generator (RNG).
key1 = Random.new().read(key_bytes)
A key may be derived from a password, too:
# It's also possible to derive a key from a password, but it's important that
# the password have high entropy, meaning difficult to predict.
password = "This is a rather weak password."
# For added # security, we add a "salt", which increases the entropy.
#
# In this example, we use the same RNG to produce the salt that we used to
# produce key1.
salt_bytes = 8
salt = Random.new().read(salt_bytes)
# Stands for "Password-based key derivation function 2"
key2 = PBKDF2(password, salt, key_bytes)
Some solutions above suggest using SHA-256 for deriving the key, but this is generally considered bad cryptographic practice.
Check out Wikipedia for more on modes of operation.
I am grateful for the other answers which inspired me, but it didn't work for me.
After spending hours trying to figure out how it works, I came up with the implementation below with the newest PyCryptodomex library (it is another story how I managed to set it up behind proxy, on Windows, in a virtualenv... phew)
It is working on your implementation. Remember to write down padding, encoding, and encrypting steps (and vice versa). You have to pack and unpack, keeping in mind the order.
import base64
import hashlib
from Cryptodome.Cipher import AES
from Cryptodome.Random import get_random_bytes
__key__ = hashlib.sha256(b'16-character key').digest()
def encrypt(raw):
BS = AES.block_size
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
raw = base64.b64encode(pad(raw).encode('utf8'))
iv = get_random_bytes(AES.block_size)
cipher = AES.new(key= __key__, mode= AES.MODE_CFB,iv= iv)
return base64.b64encode(iv + cipher.encrypt(raw))
def decrypt(enc):
unpad = lambda s: s[:-ord(s[-1:])]
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(__key__, AES.MODE_CFB, iv)
return unpad(base64.b64decode(cipher.decrypt(enc[AES.block_size:])).decode('utf8'))
For someone who would like to use urlsafe_b64encode and urlsafe_b64decode, here are the version that're working for me (after spending some time with the unicode issue)
BS = 16
key = hashlib.md5(settings.SECRET_KEY).hexdigest()[:BS]
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
unpad = lambda s : s[:-ord(s[len(s)-1:])]
class AESCipher:
def __init__(self, key):
self.key = key
def encrypt(self, raw):
raw = pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return base64.urlsafe_b64encode(iv + cipher.encrypt(raw))
def decrypt(self, enc):
enc = base64.urlsafe_b64decode(enc.encode('utf-8'))
iv = enc[:BS]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return unpad(cipher.decrypt(enc[BS:]))
You can get a passphrase out of an arbitrary password by using a cryptographic hash function (NOT Python's builtin hash) like SHA-1 or SHA-256. Python includes support for both in its standard library:
import hashlib
hashlib.sha1("this is my awesome password").digest() # => a 20 byte string
hashlib.sha256("another awesome password").digest() # => a 32 byte string
You can truncate a cryptographic hash value just by using [:16] or [:24] and it will retain its security up to the length you specify.
Another take on this (heavily derived from solutions above) but
uses null for padding
does not use lambda (never been a fan)
tested with python 2.7 and 3.6.5
#!/usr/bin/python2.7
# you'll have to adjust for your setup, e.g., #!/usr/bin/python3
import base64, re
from Crypto.Cipher import AES
from Crypto import Random
from django.conf import settings
class AESCipher:
"""
Usage:
aes = AESCipher( settings.SECRET_KEY[:16], 32)
encryp_msg = aes.encrypt( 'ppppppppppppppppppppppppppppppppppppppppppppppppppppppp' )
msg = aes.decrypt( encryp_msg )
print("'{}'".format(msg))
"""
def __init__(self, key, blk_sz):
self.key = key
self.blk_sz = blk_sz
def encrypt( self, raw ):
if raw is None or len(raw) == 0:
raise NameError("No value given to encrypt")
raw = raw + '\0' * (self.blk_sz - len(raw) % self.blk_sz)
raw = raw.encode('utf-8')
iv = Random.new().read( AES.block_size )
cipher = AES.new( self.key.encode('utf-8'), AES.MODE_CBC, iv )
return base64.b64encode( iv + cipher.encrypt( raw ) ).decode('utf-8')
def decrypt( self, enc ):
if enc is None or len(enc) == 0:
raise NameError("No value given to decrypt")
enc = base64.b64decode(enc)
iv = enc[:16]
cipher = AES.new(self.key.encode('utf-8'), AES.MODE_CBC, iv )
return re.sub(b'\x00*$', b'', cipher.decrypt( enc[16:])).decode('utf-8')
For the benefit of others, here is my decryption implementation which I got to by combining the answers of #Cyril and #Marcus. This assumes that this coming in via HTTP Request with the encryptedText quoted and base64 encoded.
import base64
import urllib2
from Crypto.Cipher import AES
def decrypt(quotedEncodedEncrypted):
key = 'SecretKey'
encodedEncrypted = urllib2.unquote(quotedEncodedEncrypted)
cipher = AES.new(key)
decrypted = cipher.decrypt(base64.b64decode(encodedEncrypted))[:16]
for i in range(1, len(base64.b64decode(encodedEncrypted))/16):
cipher = AES.new(key, AES.MODE_CBC, base64.b64decode(encodedEncrypted)[(i-1)*16:i*16])
decrypted += cipher.decrypt(base64.b64decode(encodedEncrypted)[i*16:])[:16]
return decrypted.strip()
I have used both Crypto and PyCryptodomex library and it is blazing fast...
import base64
import hashlib
from Cryptodome.Cipher import AES as domeAES
from Cryptodome.Random import get_random_bytes
from Crypto import Random
from Crypto.Cipher import AES as cryptoAES
BLOCK_SIZE = AES.block_size
key = "my_secret_key".encode()
__key__ = hashlib.sha256(key).digest()
print(__key__)
def encrypt(raw):
BS = cryptoAES.block_size
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
raw = base64.b64encode(pad(raw).encode('utf8'))
iv = get_random_bytes(cryptoAES.block_size)
cipher = cryptoAES.new(key= __key__, mode= cryptoAES.MODE_CFB,iv= iv)
a= base64.b64encode(iv + cipher.encrypt(raw))
IV = Random.new().read(BLOCK_SIZE)
aes = domeAES.new(__key__, domeAES.MODE_CFB, IV)
b = base64.b64encode(IV + aes.encrypt(a))
return b
def decrypt(enc):
passphrase = __key__
encrypted = base64.b64decode(enc)
IV = encrypted[:BLOCK_SIZE]
aes = domeAES.new(passphrase, domeAES.MODE_CFB, IV)
enc = aes.decrypt(encrypted[BLOCK_SIZE:])
unpad = lambda s: s[:-ord(s[-1:])]
enc = base64.b64decode(enc)
iv = enc[:cryptoAES.block_size]
cipher = cryptoAES.new(__key__, cryptoAES.MODE_CFB, iv)
b= unpad(base64.b64decode(cipher.decrypt(enc[cryptoAES.block_size:])).decode('utf8'))
return b
encrypted_data =encrypt("Hi Steven!!!!!")
print(encrypted_data)
print("=======")
decrypted_data = decrypt(encrypted_data)
print(decrypted_data)
You can use a scheme like PKCS#7 padding. You can use it instead the previous functions to pad (when doing encryption) and unpad (when doing decryption). I will provide the full source code below.
import base64
import hashlib
from Crypto import Random
from Crypto.Cipher import AES
import pkcs7
class Encryption:
def __init__(self):
pass
def Encrypt(self, PlainText, SecurePassword):
pw_encode = SecurePassword.encode('utf-8')
text_encode = PlainText.encode('utf-8')
key = hashlib.sha256(pw_encode).digest()
iv = Random.new().read(AES.block_size)
cipher = AES.new(key, AES.MODE_CBC, iv)
pad_text = pkcs7.encode(text_encode)
msg = iv + cipher.encrypt(pad_text)
EncodeMsg = base64.b64encode(msg)
return EncodeMsg
def Decrypt(self, Encrypted, SecurePassword):
decodbase64 = base64.b64decode(Encrypted.decode("utf-8"))
pw_encode = SecurePassword.decode('utf-8')
iv = decodbase64[:AES.block_size]
key = hashlib.sha256(pw_encode).digest()
cipher = AES.new(key, AES.MODE_CBC, iv)
msg = cipher.decrypt(decodbase64[AES.block_size:])
pad_text = pkcs7.decode(msg)
decryptedString = pad_text.decode('utf-8')
return decryptedString
import StringIO
import binascii
def decode(text, k=16):
nl = len(text)
val = int(binascii.hexlify(text[-1]), 16)
if val > k:
raise ValueError('Input is not padded or padding is corrupt')
l = nl - val
return text[:l]
def encode(text, k=16):
l = len(text)
output = StringIO.StringIO()
val = k - (l % k)
for _ in xrange(val):
output.write('%02x' % val)
return text + binascii.unhexlify(output.getvalue())
See mnothic's answer.
Compatible UTF-8 encoding:
def _pad(self, s):
s = s.encode()
res = s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs).encode()
return res
PyCrypto is old and busted.
The cryptography has better support these days.
Here's another implementation. Note that this returns bytes, you'd need to use base64 to convert them to a string for transmission.
import os
import hashlib
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
_BLOCK_SIZE = 16
class AesStringCipher:
def __init__(self, key):
self._key = hashlib.sha256(key.encode()).digest()
def encrypt_str(self, raw:str) -> bytes:
iv = os.urandom(_BLOCK_SIZE)
cipher = Cipher(algorithms.AES(self._key), modes.CBC(iv), default_backend())
encryptor = cipher.encryptor()
raw = _pad(raw)
return iv + encryptor.update(raw.encode('utf-8')) + encryptor.finalize()
def decrypt_str(self, enc:bytes) -> str:
iv = enc[:_BLOCK_SIZE]
enc = enc[_BLOCK_SIZE:]
cipher = Cipher(algorithms.AES(self._key), modes.CBC(iv), default_backend())
decryptor = cipher.decryptor()
raw = decryptor.update(enc) + decryptor.finalize()
raw = raw.decode('utf-8')
return _unpad(raw)
def _pad(s:str) -> str:
padding = (_BLOCK_SIZE - (len(s) % _BLOCK_SIZE))
return s + padding * chr(padding)
def _unpad(s:str) -> str:
return s[:-ord(s[len(s)-1:])]
if __name__ == '__main__':
cipher = AesStringCipher('my secret password')
secret_msg = 'this is a super secret msg ...'
enc_msg = cipher.encrypt_str(secret_msg)
dec_msg = cipher.decrypt_str(enc_msg)
assert secret_msg == dec_msg
Encryption and decryption of Latin and special characters (Chinese) using AES-256 with utf8mb4:
For those who need to encrypt and decrypt Latin and special values, such as Chinese, here is a modification of the #MIkee code to do this task.
Remembering that UTF-8 alone does not handle this type of encoding.
import base64, re
from Crypto.Cipher import AES
from Crypto import Random
from django.conf import settings
import codecs
# Make utf8mb4 recognizable.
codecs.register(lambda name: codecs.lookup('utf8') if name == 'utf8mb4' else None)
class AESCipher:
def __init__(self, key, blk_sz):
self.key = key
self.blk_sz = blk_sz
def encrypt( self, raw ):
# raw is the main value
if raw is None or len(raw) == 0:
raise NameError("No value given to encrypt")
raw = raw + '\0' * (self.blk_sz - len(raw) % self.blk_sz)
raw = raw.encode('utf8mb4')
# Initialization vector to avoid same encrypt for same strings.
iv = Random.new().read( AES.block_size )
cipher = AES.new( self.key.encode('utf8mb4'), AES.MODE_CFB, iv )
return base64.b64encode( iv + cipher.encrypt( raw ) ).decode('utf8mb4')
def decrypt( self, enc ):
# enc is the encrypted value
if enc is None or len(enc) == 0:
raise NameError("No value given to decrypt")
enc = base64.b64decode(enc)
iv = enc[:16]
# AES.MODE_CFB that allows bigger length or Latin values
cipher = AES.new(self.key.encode('utf8mb4'), AES.MODE_CFB, iv )
return re.sub(b'\x00*$', b'', cipher.decrypt( enc[16:])).decode('utf8mb4')
Usage:
>>> from django.conf import settings
>>> from aesencryption import AESCipher
>>>
>>> aes = AESCipher(settings.SECRET_KEY[:16], 32)
>>>
>>> value = aes.encrypt('漢字')
>>>
>>> value
'hnuRwBjwAHDp5X0DmMF3lWzbjR0r81WlW9MRrWukgQwTL0ZI88oQaWvMfBM+W87w9JtSTw=='
>>> dec_value = aes.decrypt(value)
>>> dec_value
'漢字'
>>>
The same for Latin letters, such as ã, á, à, â, ã, ç, etc.
Attention point
Bear in mind that if you will store Latin values to your database, you need to set it to allow such type of data. Therefore, if your database is set as utf-8 it will not accept such type of data. You will need to change there as well.
from Crypto import Random
from Crypto.Cipher import AES
import base64
BLOCK_SIZE=16
def trans(key):
return md5.new(key).digest()
def encrypt(message, passphrase):
passphrase = trans(passphrase)
IV = Random.new().read(BLOCK_SIZE)
aes = AES.new(passphrase, AES.MODE_CFB, IV)
return base64.b64encode(IV + aes.encrypt(message))
def decrypt(encrypted, passphrase):
passphrase = trans(passphrase)
encrypted = base64.b64decode(encrypted)
IV = encrypted[:BLOCK_SIZE]
aes = AES.new(passphrase, AES.MODE_CFB, IV)
return aes.decrypt(encrypted[BLOCK_SIZE:])
You can use the new django-mirage-field package.