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Encrypting mulitple files with hybrid encryptions, encountering error when decrypting

Basically, i am trying to encrypt 3 files in a folder with hybrid encryption, AES CBC. Successfully encrypted all the files, but having issues decrypting. The requirements for the task is:
2 seperate files, one for encrypting and one for decrypting
IV is 24 characters
IV can be hardcoded ,all files can use the same IV in or randomised (i randomised mine)
So far, only the last file is decrypted properly, the first 2 is giving me a ValueError error. However when i printed out the IV, it seems to be correct. Can someone advise me on this?
Encryption code
`#!/usr/bin/env python3
from base64 import b64encode
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad
from Crypto.Random import get_random_bytes
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
import glob
for item in glob.glob("*.txt"):
skey = get_random_bytes(16)
recipent_key = RSA.import_key(open("receiver.pem").read())
file_out = open("encrypted_key.bin", "wb")
cipher_rsa = PKCS1_OAEP.new(recipent_key)
enc_data = cipher_rsa.encrypt(skey)
file_out.write(enc_data)
file_out.close()
data_in = open(item, 'rb')
data = data_in.read()
data_in.close()
cipher = AES.new(skey, AES.MODE_CBC)
ct_bytes = cipher.encrypt(pad(data, AES.block_size))
iv = b64encode(cipher.iv).decode('utf-8')
ct = b64encode(ct_bytes).decode('utf-8')
skey = b64encode(skey).decode('utf-8')
print(iv, ct, skey)
datain = (iv, ct)
Fileout = open(item,'w')
Fileout.writelines(datain)
Fileout.close()
`
Decryption code
`#!/usr/bin/env python3
from base64 import b64decode
from Crypto.Cipher import AES
from Crypto.Util.Padding import unpad
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
import os
import glob
for item in glob.glob("*.txt"):
file_in = open("encrypted_key.bin", "rb")
private_key = RSA.import_key(open("private.pem").read())
enc_data = file_in.read(private_key.size_in_bytes())
cipher_rsa = PKCS1_OAEP.new(private_key)
skey = cipher_rsa.decrypt(enc_data)
file_in.close()
in_file = open(item, "r")
data = in_file.read()
in_file.close()
print(data[0:24])
try:
iv = b64decode(data[0:24])
ct = b64decode(data[24:])
cipher = AES.new(skey, AES.MODE_CBC, iv)
pt = unpad(cipher.decrypt(ct), AES.block_size)
output = str(pt, 'utf-8')
print("the message was: ", output)
Fileout = open(item,'w')
Fileout.writelines(output)
Fileout.close()
except ValueError:
print("Incorrect decryption")
except KeyError:
print("incorrect key")
`
please send help :"")
EDIT: i realised, every round my loop goes, my key also randomise. that's the problem, i solved it :")

Crypting in python using hashlib

I have this piece of code
import hashlib
from Cryptodome.Cipher import AES
decryption_key = hashlib.sha256(b"050746" + b"\x00\x00\x00\x03").digest()
iv = 16 * b '\x00'
aes = AES.new(decryption_key, AES.MODE_CBC, iv)
decrypted_nonce = aes.decrypt(encrypted_nonce)
I need help in understanding what this code is doing
I would be grateful for your help

Incorrect decryption RSA pycryptodome

I try to implement RSA in Python with pycryptodome, the encrypt Works fine but the decrypt function no, my code is the following:
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
from Crypto.Signature import pss
from Crypto.Hash import SHA256
class RSA_OBJECT:
def create_KeyPair(self):
self.key = RSA.generate(self.KEY_LENGTH)
def save_PrivateKey(self, file, password):
key_cifrada = self.key.export_key(passphrase=password, pkcs=8,protection="scryptAndAES128-CBC")
file_out = open(file, "wb")
file_out.write(key_cifrada)
file_out.close()
def load_PrivateKey(self, file, password):
key_cifrada = open(file, "rb").read()
self.private_key = RSA.import_key(key_cifrada, passphrase=password)
def save_PublicKey(self, file):
key_pub = self.key.publickey().export_key()
file_out = open(file, "wb")
file_out.write(key_pub)
file_out.close()
def load_PublicKey(self, file):
key_publica = open(file, "rb").read()
self.public_key = RSA.import_key(key_publica)
I don't know why, because I think that the code is correct, anyone can help me?

Your problem you generate two different keys;
self.public_key = RSA.generate(self.KEY_LENGTH)
self.private_key = RSA.generate(self.KEY_LENGTH)
you should;
key = RSA.generate(self.KEY_LENGTH)
and
private_key = key.export_key()
file_out = open("private.pem", "wb")
file_out.write(private_key)
public_key = key.publickey().export_key()
file_out = open("receiver.pem", "wb")
file_out.write(public_key)
See here in more details;
Note: note that key object has two functionality due to public keys encryption. You can write a private key into a file and public key into another. In this way, you can distribute the key. See RSAKey.

Can't use a data obj with timeit.Time module in python

I'm trying to measure how long it takes read then encrypt some data (independently). But I can't seem to access the a pre-created data obj within timeit (as it runs in its own virtual environment)
This works fine (timing file read operation):
t = timeit.Timer("""
openFile = open('mytestfile.bmp', "rb")
fileData = openFile.readlines()
openFile.close()""")
readResult = t.repeat(1,1)
print ("\Finished reading in file")
The the below doesn't work because I can't access 'fileData' obj. I can't create it again from inside the timeit function, otherwise it will increase the overall execution time.
timing encrypt operation:
tt = timeit.Timer("""
from Crypto.Cipher import AES
import os
newFile = []
key = os.urandom(32)
cipher = AES.new(key, AES.MODE_CFB)
for lines in fileData:
newFile = cipher.encrypt(lines)""")
encryptResult = tt.repeat(1,1)

timeit takes a setup argument that only runs once
from the docs:
setup: statement to be executed once
initially (default 'pass')
for example:
setup = """
from Crypto.Cipher import AES
import os
newFile = []
fileData = open('filename').read()
"""
stmt = """
key = os.urandom(32)
cipher = AES.new(key, AES.MODE_CFB)
for lines in fileData:
newFile = cipher.encrypt(lines)"""
tt = timeit.Timer(stmt, setup)
tt.repeat()

you can use the setup parameter of the timeit.Timer class like so:
tt = timeit.Timer("""
from Crypto.Cipher import AES
import os
newFile = []
key = os.urandom(32)
cipher = AES.new(key, AES.MODE_CFB)
for lines in fileData:
newFile = cipher.encrypt(lines)""",
setup = "fileData = open('mytestfile.bmp', 'rb').readlines()")
encryptResult = tt.repeat(1,1)
The setup code is only run once.

M2Crypto Encrypt/Decrypt using AES256

Can someone provide me code to encrypt / decrypt using m2crypto aes256 CBC using Python

M2Crypto's documentation is terrible. Sometimes the OpenSSL documentation (m2crypto wraps OpenSSL) can help. Your best bet is to look at the M2Crypto unit tests -- https://gitlab.com/m2crypto/m2crypto/blob/master/tests/test_evp.py -- look for the test_AES() method.

Take a look at m2secret:
Small utility and module for
encrypting and decrypting data using
symmetric-key algorithms. By default
uses 256-bit AES (Rijndael) using CBC,
but some options are configurable.
PBKDF2 algorithm used to derive key
from password.

I use following wrapper around M2Crypto (borrowed from cryptography.io):
import os
import base64
import M2Crypto
class SymmetricEncryption(object):
#staticmethod
def generate_key():
return base64.b64encode(os.urandom(48))
def __init__(self, key):
key = base64.b64decode(key)
self.iv = key[:16]
self.key = key[16:]
def encrypt(self, plaintext):
ENCRYPT = 1
cipher = M2Crypto.EVP.Cipher(alg='aes_256_cbc', key=self.key, iv=self.iv, op=ENCRYPT)
ciphertext = cipher.update(plaintext) + cipher.final()
return base64.b64encode(ciphertext)
def decrypt(self, cyphertext):
DECRYPT = 0
cipher = M2Crypto.EVP.Cipher(alg='aes_256_cbc', key=self.key, iv=self.iv, op=DECRYPT)
plaintext = cipher.update(base64.b64decode(cyphertext)) + cipher.final()
return plaintext

def encrypt_file(key, in_filename, out_filename,iv):
cipher=M2Crypto.EVP.Cipher('aes_256_cfb',key,iv, op=1)
with open(in_filename, 'rb') as infile:
with open(out_filename, 'wb') as outfile:
outfile.write(b)
while True:
buf = infile.read(1024)
if not buf:
break
outfile.write(cipher.update(buf))
outfile.write( cipher.final() )
outfile.close()
infile.close()
def decrypt_file(key, in_filename, out_filename,iv):
cipher = M2Crypto.EVP.Cipher("aes_256_cfb",key , iv, op = 0)
with open(in_filename, 'rb') as infile:
with open(out_filename, 'wb') as outfile:
while True:
buf = infile.read(1024)
if not buf:
break
try:
outfile.write(cipher.update(buf))
except:
print "here"
outfile.write( cipher.final() )
outfile.close()
infile.close()

When it comes to security nothing beats reading the documentation.
http://chandlerproject.org/bin/view/Projects/MeTooCrypto
Even if I took the time to understand and make the perfect code for you to copy and paste, you would have no idea if I did a good job or not. Not very helpful I know, but I wish you luck and secure data.