Develop Reference

Can I decrypt openssl encrypted data using any dependancy?

I have used openssl to encrypt data using below command:
openssl cms -encrypt -in test.data -inform PEM -recip certificate.pem -outform PEM -out test_encrypted_data.txt
Now I want to decrypt above encrypted data using python. I have tried below code, but it is not working and is throwing:
ValueError: Ciphertext with incorrect length.
Code:
from Crypto.Cipher import PKCS1_OAEP, AES
from Crypto.PublicKey import RSA
from OpenSSL import crypto
import base64
data = open("test_encrypted_data.txt").read()
data = data.replace("-----BEGIN CMS-----", "").replace("-----END CMS-----", "")
data = base64.b64decode(data)
private_key = RSA.import_key(open("private_key_no_pass.pem").read())
decryptor = PKCS1_OAEP.new(private_key)
decryptedtext = decryptor.decrypt(data)
print(f"Decrypted Text : {decryptedtext.decode()}")

Check if openssl des 'base64' encode.
Probably -base64 parameter is missing in openssl.
So the text is encrypted but not base64 coded by openssl, and then your code does base64 decode and decrypts it.

Thanks all I have used openssl commands to decrypt file in python
decrypted_data = subprocess.check_output(
f'echo "{encryptedtext}" | openssl cms -decrypt -inkey services/private_key_no_pass.pem -inform PEM ',
shell=True)

"Incorrect decryption" in decryption RSA python code

i have this code that suppose to decode base64 encoded RSA text (by its key) but it doesn't work.
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
import binascii
import base64
f = open('mykey.pem','r')
keyPair = RSA.import_key(f.read())
encoded = b'base64_encoded_text'
encrypted = base64.decodebytes(encoded)
decryptor = PKCS1_OAEP.new(keyPair)
decrypted = decryptor.decrypt(encrypted)
print('Decrypted:', decrypted)
The error is: "Incorrect decryption".
Does somebody know what could be the problem?

encrypt text message using rsa public key

I have been given a public key by my client, and I want to send him a text message which would be encrypted with his public key. The public key is with .pub extension.
I am trying to do this in bash via openssl command and via python using pycrypto module with no luck. I am a novice with no experience in cryptography.
How can I go about this.Thanks in advance
public_key

Suppositions:
The public key given by your client is in "key.pub" file
Taking the input from the user at run time for the string or text to be encrypted in a variable named, "msg".
Already installed Crypto.PublicKey library using command "sudo pip install Crypto.PublicKey"
Code:
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_v1_5 as Cipher_PKCS1_v1_5
with open("key.pub", 'r') as f1:
pubkey = f1.read()
msg = raw_input("Enter String to be encrypted: ")
print("raw string->", msg)
keyPub = RSA.importKey(pubkey) # import the public key
cipher = Cipher_PKCS1_v1_5.new(keyPub)
cipher_text = cipher.encrypt(msg.encode()) # now we have the cipher
print("cipher text->", cipher_text)
Format for the Key in the file:
The format of key in the file should be like this,
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAybVqRvfYvWbLsB98BqkD
lWd0/5y6SyhHt6/r6M0l7JXBweqMvxVt7XmI2yqPL56YxzcgQ8ycDkoqHJ+XozgP
iRnLNpYRlCzsiaOElbmQcnrI8iOb9Ahm6j0cbBB1S8VNvD+u9RQJt53zPxPj8/Dq
f1oNGFXOM8udNYWZaRCukLs/TumsAn0a+BF4639WtFiUvTWdVhlyvCQTs49ytRkH
rXH30RkB528RIvTGeW8xBTV4NaiTIzAEKCVSPagLr4Hzbb9b5+bODic/zkLGQazy
/NKOFgiB7kD2+WEMcuhTr5noeXau0PDAhgmrBhzzWOjUwwaO+ACvJLkPXZfjhy7P
+wIDAQAB
-----END PUBLIC KEY-----

Creating RSA signature using node.js and verifying using python

I'm trying to create a signature in node using this code:
var crypto = require('crypto');
var data = 'some data'
var signer = crypto.createSign('RSA-SHA256');
signer.write(data, 'base64');
signer.end();
var signature = signer.sign(privateKey, 'base64');
The signature and data are sent to python server.
Now I'm want to verify it using python code:
from base64 import b64decode, b64encode
from Crypto.Hash import SHA256
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5
rsakey = RSA.importKey(public_key)
signer = PKCS1_v1_5.new(rsakey)
digest = SHA256.new()
digest.update(data)
signer.verify(digest, b64decode(signature))
The verification fails.
When I use the same language for both sign and verify it works.
Any thoughts?

I had the same problem, and have found this to work:
import rsa
rsa.verify(message, signature, public_key)

Decrypt using an RSA public key with PyCrypto

As far as I understand, I should be able to use RSA to ensure authenticity or privacy, as I wish. In my case, I want to ensure authenticity so I encrypt the data with the private key and allow anyone to decrypt it with the public key. The data is not really secret but I need to guarantee that it was created by the owner of the public (and private) key.
When I try to decrypt using PyCrypto I get No private key error from PyCrypto. The code is this:
def _decrypt_rsa(decrypt_key_file, cipher_text):
from Crypto.PublicKey import RSA
from base64 import b64decode
key = open(decrypt_key_file, "r").read()
rsakey = RSA.importKey(key)
raw_cipher_data = b64decode(cipher_text)
decrypted = rsakey.decrypt(raw_cipher_data)
return decrypted
I'm calling it with the path to the public key file (in OpenSSH format.) The encrypted data isn't generated by me and it was not done with Python but PHP. In PHP there's a openssl_public_decrypt function that decrypts this data easily.
Is it possible at all to decrypt using the public key with PyCrypto?

That is totally insecure, because you are using raw RSA without padding.
Your application needs a signature, so you should not be dealing with encryptions and decryptions. For instance, PKCS#1 v1.5 is a good protocol, even though the signature is a piece of data that must be appended to what you want to prove the authenticity of.
To verify a PKCS#1 v1.5 signature in Python, you do:
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5
from Crypto.Hash import SHA
rsa_key = RSA.importKey(open(verification_key_file, "rb").read())
verifier = PKCS1_v1_5.new(rsa_key)
h = SHA.new(data_to_verify)
if verifier.verify(h, signature_received_with_the_data):
print "OK"
else:
print "Invalid"
I would strongly recommend to change the PHP code so that it creates such a signature.

Your function is correct. You just need to be giving it the path to your private key in order to decrypt instead of your public key. The public key is for encrypting, the private key is for decrypting.
def _decrypt_rsa(decrypt_key_file, cipher_text):
'''
Decrypt RSA encrypted package with private key
:param decrypt_key_file: Private key
:param cipher_text: Base64 encoded string to decrypt
:return: String decrypted
'''
from Crypto.PublicKey import RSA
from base64 import b64decode
key = open(decrypt_key_file, "r").read()
rsakey = RSA.importKey(key)
#optionally could use OAEP
#from Crypto.Cipher import PKCS1_OAEP
#rsakey = PKCS1_OAEP.new(rsakey)
raw_cipher_data = b64decode(cipher_text)
decrypted = rsakey.decrypt(raw_cipher_data)
return decrypted