The crypt.py script will generate bcrypt, md5-crypt, sha256-crypt, sha512-crypt hashes. This is using vanilla python, so it will work on Windows as well. Also, I like Python 2 so it works in both Python2 and Python3.
Todo: Thinking about adding yescrypt, since my Debian boxes use that by default.
These are a native Python implementation of blowfish and bcrypt. Obviously blowfish will run slower in pure Python than in C, but I wanted to do it. Currently only supports the "$2b$" hash-type, but I might work on implementing "$2a$" as well.
To learn! Sometimes in discussion, the concept of "salting" a password comes up. In a similar vein, sometimes the question of "why dont linux password hashes look like a md5/sha hash digest?" also rises. I knew conceptually how to answer these questions: salting "adds" to a password to help prevent precomputed attacks like rainbow tables, and the linux crypt hashes are actually base64'd.
My simple explanation was:
hash = sha512(salt+password)
for _ in range(5000):
hash = sha512(hash)
base64(hash)
But! I had never looked at the codebase to understand EXACTLY how sha512-crypt worked. Thus this little project was born.
I found the source code of sha512-crypt here: https://elixir.bootlin.com/glibc/latest/source/crypt
From that start, I analyzed it and converted it over to Python. After finishing the sha512-crypt portion, I took a peek at sha256-crypt. I found that the code was mostly identical, so I included it! In the C portion of the code, I removed most of the codebase since the only thing I am interested in is producing sha512-crypt hashes, like on a linux machine.
Most of the edits to the source are just printf to output "Hey this is what the hash output looks like".
You can use the python code like a library, but since I included a if __name__ == "__main__" you can also use it on the commandline:
Usage: ./crypt.py <password> <hash> <rounds>
# Note: rounds is optional, it defaults to 5000 (or hardcoded to 1000 for md5)
The C code only supports sha512-crypt. I just needed something to test with since I didn't want to do complete static analysis. I included the source here in case anyone else wants to go down that path.
make
./sha512crypt <password> <salt> <rounds>
./sha512crypt password saltines 0
This does let you do 0 rounds, I wanted this for testing purposes. You can also have any length salt.