I am trying to make a program to decrypt via python. The cipher used is AES-CBC.
But I get this error and I don't know how to fix it. Do you have any ideas?
Thanks in advance
#!/usr/bin/env python3
import base64
import binascii
from Crypto.Cipher import AES
key = "YELLOW SUBMARINE"
iv_dec = "a5f6ba42255643907a5bb3709840ca5b"
block_size = 16
pad_char = u"\00"
pad = lambda s: s + (block_size - len(s) % block_size) * pad_char
ciphertext = "412053617563657266756c206f662053656372657473"
# Decrypt
aes_dec = AES.new(str(key), AES.MODE_CBC, str(iv_dec))
decrypted = aes_dec.decrypt(ciphertext)
print ("Decrypted text: {} ".format(decrypted.rstrip(pad_char)))
I need to port old Python 2 code to Python 3 and I think I'm messing up with string encoding.
It's a custom password hasher.
I've tried different ways, unsuccessfully, obtaining only errors or wrong results.
This is the Python 2 code which needs to work with Python 3:
from hashlib import sha256
from base64 import b64encode
# 32 characters length string
SALT = "SQ7HqXQhrOIPEALbI7QhVjZ3DHJGhK18"
PLAIN_PASSWORD = "PLAIN_PASSWORD"
SALTED_PASSWORD = "%s{%s}" % (PLAIN_PASSWORD, SALT)
digest = ""
for i in range(100):
digest = sha256(digest + SALTED_PASSWORD).digest()
print b64encode(digest)
Output:
Yb0W9H+R7xQDStPfBjKMjFbe05jDPK6OXrdhVWCDJrU=
Operate on bytes from the beginning:
SALTED_PASSWORD = ("%s{%s}" % (PLAIN_PASSWORD, SALT)).encode()
digest = b""
for i in range(100):
digest = sha256(digest + SALTED_PASSWORD).digest()
print(b64encode(digest).decode())
# Yb0W9H+R7xQDStPfBjKMjFbe05jDPK6OXrdhVWCDJrU=
from hashlib import sha256
from base64 import b64encode
# 32 characters length string
SALT = b"SQ7HqXQhrOIPEALbI7QhVjZ3DHJGhK18"
PLAIN_PASSWORD = b"PLAIN_PASSWORD"
SALTED_PASSWORD = b"%s{%s}" % (PLAIN_PASSWORD, SALT)
digest = b""
for i in range(100):
digest = sha256(digest + SALTED_PASSWORD).digest()
print(b64encode(digest))
from docx import Document
from Crypto.Cipher import AES
document = Document('test.docx')
allText = ""
for docpara in document.paragraphs:
allText+=(docpara.text)
key="1234567891011121"
cipher=AES.new(key,AES.MODE_ECB)
msg=cipher.encrypt(allText)
I want to encrypt a Docx file in python.But when i run this code:
raise TypeError("Object type %s cannot be passed to C code" % type(data))
TypeError: Object type cannot be passed to C code
How can i solve this problem?
From the documentation:
>>> from Crypto.Cipher import AES
>>> from Crypto import Random
>>>
>>> key = b'Sixteen byte key'
>>> iv = Random.new().read(AES.block_size)
>>> cipher = AES.new(key, AES.MODE_CFB, iv)
>>> msg = iv + cipher.encrypt(b'Attack at dawn')
I think your key needs to be converted to bytes first, and the object to be encrypted too. Notice the b' before both.
You also need to add an initialization vector (iv) to use for the encryption.
I am using pycrypto module for AES encryption. And using documentation I have write down the below function but it al;ways gives error IV must be 16 bytes long but I am using 16 byte long IV.
def aes_encrypt(plaintext):
"""
"""
key = **my key comes here**
iv = binascii.hexlify(os.urandom(16)) # even used without binascii.hexlify)
aes_mode = AES.MODE_CBC
obj = AES.new(key, aes_mode, iv)
ciphertext = obj.encrypt(plaintext)
return ciphertext
Use this:
from Crypto.Cipher import AES
import binascii,os
def aes_encrypt(plaintext):
key = "00112233445566778899aabbccddeeff"
iv = os.urandom(16)
aes_mode = AES.MODE_CBC
obj = AES.new(key, aes_mode, iv)
ciphertext = obj.encrypt(plaintext)
return ciphertext
Works as below:
>>> aes_encrypt("TestTestTestTest")
'r_\x18\xaa\xac\x9c\xdb\x18n\xc1\xa4\x98\xa6sm\xd3'
>>>
That's the difference:
>>> iv = binascii.hexlify(os.urandom(16))
>>> iv
'9eae3db51f96e53f94dff9c699e9e849'
>>> len(iv)
32
>>> iv = os.urandom(16)
>>> iv
'\x16fdw\x9c\xe54]\xc2\x12!\x95\xd7zF\t'
>>> len(iv)
16
>>>
I am trying to encode a text string to base64.
i tried doing this :
name = "your name"
print('encoding %s in base64 yields = %s\n'%(name,name.encode('base64','strict')))
But this gives me the following error:
LookupError: 'base64' is not a text encoding; use codecs.encode() to handle arbitrary codecs
How do I go about doing this ? ( using Python 3.4)
Remember to import base64 and that b64encode takes bytes as an argument.
import base64
b = base64.b64encode(bytes('your string', 'utf-8')) # bytes
base64_str = b.decode('utf-8') # convert bytes to string
It turns out that this is important enough to get it's own module...
import base64
base64.b64encode(b'your name') # b'eW91ciBuYW1l'
base64.b64encode('your name'.encode('ascii')) # b'eW91ciBuYW1l'
For py3, base64 encode and decode string:
import base64
def b64e(s):
return base64.b64encode(s.encode()).decode()
def b64d(s):
return base64.b64decode(s).decode()
1) This works without imports in Python 2:
>>>
>>> 'Some text'.encode('base64')
'U29tZSB0ZXh0\n'
>>>
>>> 'U29tZSB0ZXh0\n'.decode('base64')
'Some text'
>>>
>>> 'U29tZSB0ZXh0'.decode('base64')
'Some text'
>>>
(although this doesn't work in Python3 )
2) In Python 3 you'd have to import base64 and do base64.b64decode('...')
- will work in Python 2 too.
To compatibility with both py2 and py3
import six
import base64
def b64encode(source):
if six.PY3:
source = source.encode('utf-8')
content = base64.b64encode(source).decode('utf-8')
It looks it's essential to call decode() function to make use of actual string data even after calling base64.b64decode over base64 encoded string. Because never forget it always return bytes literals.
import base64
conv_bytes = bytes('your string', 'utf-8')
print(conv_bytes) # b'your string'
encoded_str = base64.b64encode(conv_bytes)
print(encoded_str) # b'eW91ciBzdHJpbmc='
print(base64.b64decode(encoded_str)) # b'your string'
print(base64.b64decode(encoded_str).decode()) # your string
Whilst you can of course use the base64 module, you can also to use the codecs module (referred to in your error message) for binary encodings (meaning non-standard & non-text encodings).
For example:
import codecs
my_bytes = b"Hello World!"
codecs.encode(my_bytes, "base64")
codecs.encode(my_bytes, "hex")
codecs.encode(my_bytes, "zip")
codecs.encode(my_bytes, "bz2")
This can come in useful for large data as you can chain them to get compressed and json-serializable values:
my_large_bytes = my_bytes * 10000
codecs.decode(
codecs.encode(
codecs.encode(
my_large_bytes,
"zip"
),
"base64"),
"utf8"
)
Refs:
https://docs.python.org/3/library/codecs.html#binary-transforms
https://docs.python.org/3/library/codecs.html#standard-encodings
https://docs.python.org/3/library/codecs.html#text-encodings
Use the below code:
import base64
#Taking input through the terminal.
welcomeInput= raw_input("Enter 1 to convert String to Base64, 2 to convert Base64 to String: ")
if(int(welcomeInput)==1 or int(welcomeInput)==2):
#Code to Convert String to Base 64.
if int(welcomeInput)==1:
inputString= raw_input("Enter the String to be converted to Base64:")
base64Value = base64.b64encode(inputString.encode())
print "Base64 Value = " + base64Value
#Code to Convert Base 64 to String.
elif int(welcomeInput)==2:
inputString= raw_input("Enter the Base64 value to be converted to String:")
stringValue = base64.b64decode(inputString).decode('utf-8')
print "Base64 Value = " + stringValue
else:
print "Please enter a valid value."
Base64 encoding is a process of converting binary data to an ASCII
string format by converting that binary data into a 6-bit character
representation. The Base64 method of encoding is used when binary
data, such as images or video, is transmitted over systems that are
designed to transmit data in a plain-text (ASCII) format.
Follow this link for further details about understanding and working of base64 encoding.
For those who want to implement base64 encoding from scratch for the sake of understanding, here's the code that encodes the string to base64.
encoder.py
#!/usr/bin/env python3.10
class Base64Encoder:
#base64Encoding maps integer to the encoded text since its a list here the index act as the key
base64Encoding:list = None
#data must be type of str or bytes
def encode(data)->str:
#data = data.encode("UTF-8")
if not isinstance(data, str) and not isinstance(data, bytes):
raise AttributeError(f"Expected {type('')} or {type(b'')} but found {type(data)}")
if isinstance(data, str):
data = data.encode("ascii")
if Base64Encoder.base64Encoding == None:
#construction base64Encoding
Base64Encoder.base64Encoding = list()
#mapping A-Z
for key in range(0, 26):
Base64Encoder.base64Encoding.append(chr(key + 65))
#mapping a-z
for key in range(0, 26):
Base64Encoder.base64Encoding.append(chr(key + 97))
#mapping 0-9
for key in range(0, 10):
Base64Encoder.base64Encoding.append(chr(key + 48))
#mapping +
Base64Encoder.base64Encoding.append('+')
#mapping /
Base64Encoder.base64Encoding.append('/')
if len(data) == 0:
return ""
length=len(data)
bytes_to_append = -(length%3)+(3 if length%3 != 0 else 0)
#print(f"{bytes_to_append=}")
binary_list = []
for s in data:
ascii_value = s
binary = f"{ascii_value:08b}"
#binary = bin(ascii_value)[2:]
#print(s, binary, type(binary))
for bit in binary:
binary_list.append(bit)
length=len(binary_list)
bits_to_append = -(length%6) + (6 if length%6 != 0 else 0)
binary_list.extend([0]*bits_to_append)
#print(f"{binary_list=}")
base64 = []
value = 0
for index, bit in enumerate(reversed(binary_list)):
#print (f"{bit=}")
#converting block of 6 bits to integer value
value += ( 2**(index%6) if bit=='1' else 0)
#print(f"{value=}")
#print(bit, end = '')
if (index+1)%6 == 0:
base64.append(Base64Encoder.base64Encoding[value])
#print(' ', end="")
#resetting value
value = 0
pass
#print()
#padding if there is less bytes and returning the result
return ''.join(reversed(base64))+''.join(['=']*bytes_to_append)
testEncoder.py
#!/usr/bin/env python3.10
from encoder import Base64Encoder
if __name__ == "__main__":
print(Base64Encoder.encode("Hello"))
print(Base64Encoder.encode("1 2 10 13 -7"))
print(Base64Encoder.encode("A"))
with open("image.jpg", "rb") as file_data:
print(Base64Encoder.encode(file_data.read()))
Output:
$ ./testEncoder.py
SGVsbG8=
MSAyIDEwIDEzIC03
QQ==