pyargon2

Simultaneously the simplest and most powerful implementation of Argon2 in Python.

Installation

pip install pyargon2

Compatibility

• pyargon2 now only supports Python 3.9 and beyond.

Basic Usage

The hash function supports basic password hashing using the Argon2id variant and mandates password and salt strings. The resulting hash returned is hex encoded.

from pyargon2 import hash

password = 'a strong password'
salt = 'a unique salt'
hex_encoded_hash = hash(password, salt)

The default parameters aim to generate hashes in around 0.5 seconds and are targeted at a machine housing a CPU with 4 cores and at least 4GB of RAM. If timing differs significantly on your machine, adjust the parameters using the advanced options below. Remember password hashing should be slow for security so don't optimise for speed!

Advanced Usage

Function Parameters

The hash function takes in the following parameters:

Positional

• password : A string representing a password.
• salt : A string representing a unique salt.

Keyword

• pepper : A secret string to fold into the hash of the password.
• hash_len : The length in bytes of the resulting hash.
• time_cost : The number of iterations to perform.
• memory_cost : The number of kibibytes in memory to utilise.
• parallelism : The number of independent computations chains (lanes) to run.
• flags : Flags to determine which fields are securely wiped.
• variant : Argon2 algorithm variant ('i', 'd', or 'id').
• version : Argon2 algorithm version number.
• encoding : Encoding for the returned hash type ('raw', 'hex' or 'b64').

For assistance with parameter selection refer to RFC 9106, in particular "Chapter 4: Parameter Choice".

Function Exceptions

Exceptions generated by the underlying Argon2 hashing function are raised under the Argon2Error class which can be imported as follows:

from pyargon2 import Argon2Error