Tutorial by Examples

The hashlib module allows creating message digest generators via the new method. These generators will turn an arbitrary string into a fixed-length digest: import hashlib h = hashlib.new('sha256') h.update(b'Nobody expects the Spanish Inquisition.') h.digest() # ==> b'.\xdf\xda\xdaVR[\x12\...

hashlib.new requires the name of an algorithm when you call it to produce a generator. To find out what algorithms are available in the current Python interpreter, use hashlib.algorithms_available: import hashlib hashlib.algorithms_available # ==> {'sha256', 'DSA-SHA', 'SHA512', 'SHA224', 'dsa...

The PBKDF2 algorithm exposed by hashlib module can be used to perform secure password hashing. While this algorithm cannot prevent brute-force attacks in order to recover the original password from the stored hash, it makes such attacks very expensive. import hashlib import os salt = os.urandom...

A hash is a function that converts a variable length sequence of bytes to a fixed length sequence. Hashing files can be advantageous for many reasons. Hashes can be used to check if two files are identical or verify that the contents of a file haven't been corrupted or changed. You can use hashlib ...

Python's built-in crypto functionality is currently limited to hashing. Encryption requires a third-party module like pycrypto. For example, it provides the AES algorithm which is considered state of the art for symmetric encryption. The following code will encrypt a given message using a passphrase...

RSA can be used to create a message signature. A valid signature can only be generated with access to the private RSA key, validating on the other hand is possible with merely the corresponding public key. So as long as the other side knows your public key they can verify the message to be signed by...

Asymmetric encryption has the advantage that a message can be encrypted without exchanging a secret key with the recipient of the message. The sender merely needs to know the recipients public key, this allows encrypting the message in such a way that only the designated recipient (who has the corre...