However, there are malicious uses of encryption, such as building ransomware we have a tutorial on how to build such a tool. In fact, if you're reading this, then your browser is securely connected to this website (i.e., encryption). There are many encryption uses in the real world. The library we gonna use is built on top of the AES algorithm. There are a lot of encryption algorithms out there. We will use symmetric encryption, which means the same key we used to encrypt data is also usable for decryption. In this tutorial, you will learn how to use Python to encrypt files or any byte object (also string objects) using the cryptography library. It is critically important because it allows you to securely protect data that you don't want anyone to see or access. So when I convert it to a string for writing to file, I'll need to convert it back to type 'tuple' when I'm decrypting.Disclosure: This post may contain affiliate links, meaning when you click the links and make a purchase, we receive a commission.Įncryption is the process of encoding a piece of information so that only authorized parties can access it.

RSAkey.encrypt(key, '') returns type 'tuple', so I figure RSA.decrypt() expects this type as well, but I can't write that type to a textfile.

The code is as follows: RSAkey = custom_readfile_function('private_key.txt', 'r')Įnc_key = custom_readfile_function('enc_key.txt', 'r')Ĭustom_writefile_function('key.txt', str(aes_key), 'w') Return (self, ciphertext)įile '/usr/lib/python2.7/dist-packages/Crypto/PublicKey/pubkey.py', line 93, in decryptįile '/usr/lib/python2.7/dist-packages/Crypto/PublicKey/RSA.py', line 237, in _decrypt crypt(str(RSAkey.encrypt(key, '')))įile '/usr/lib/python2.7/dist-packages/Crypto/PublicKey/RSA.py', line 174, in decrypt The problem however, is that in another script, meant for decrypting enc_key to get the original AES key used to encrypt the files, trying to decrypt the enc_key which has been converted to a string produces an error: I am converting the enc_key to a string so that I can write it to a text file, otherwise enc_key.txt will contain rubbish. RSAkey = '-BEGIN PUBLIC KEY- Some RSA Key here -END PUBLIC KEY-'Ĭustom_writefile_function('enc_key.txt', enc_key)

The code is as follows: from Crypto.PublicKey import RSA The encrypted AES key will be shared with authorized persons in possession of the private key to decrypt it. I am trying to implement a script that will encrypt a file using a randomly generated AES key then encrypt said AES key with an RSA public key.

Python ciphertext file and decrypt rsa