Hide your hash function

Question

So you are tasked with creating an open source password authentication system but you want to reveal as little about the implementation of the hash function as possible. Can you write a function that takes in a password string and a salt string and outputs a salted hash string without revealing the hashing function?

End date: 6th of July

Popularity contest: So whoever is voted as hardest to figure out the hashing method.

Restriction: Must use an accepted as secure hashing function

Answer 1

Python 3

Uninspired solution - hide your hash function with hash-looking code

import base64

a = b'66726F6D20686173686C696220696D706F72742A3B7072696E74287368613235'
b = b'3628627974657328696E70757428292B696E70757428292C277574662D382729'
c = b'292E686578646967657374282929232048656C6C6F2074686572652021402324'

exec(base64.b16decode(a+b+c))

Answer 2

Ruby

Need a way to obfuscate your choice of hashing function? Why not use a hashing function?

require 'digest'

three_card_monte = %w[SHA1 MD5 RMD160]

part1, part2 = three_card_monte.repeated_permutation(2).find{|x,y|Digest(x).base64digest(y)[/tada!?/i]}

part2.send( ('mode'..$&).find{|x|Digest(part1).base64digest(x)[/\d\dSXQ/]}<<$&.to_i.chr)

puts Digest(part2).base64digest(gets+gets)

Answer 3

Python

This one is not a hashing function, takes no salt, and is completely insecure, but can you tell what it is?

def f(x):
    a,b=ord(x),ord(x)+13
    if not (97<=a<=122 or 65<=a<=90):return x
    if (65<=a<=90 and b>90) or b>122: b-=26
    return chr(b)
print(''.join(f(i) for i in input()))

It's rot13

Here is an actual hashing function.

import hashlib
salt = b'cHJpbnQoaGFzaGxpYi5zaGEyNTYoYnl0ZXMoaW5wdXQoKStpbnB1dCgpLCd1dGYtOCcpKS5oZXhkaWdlc3QoKSkKZXhpdCgp';import base64;exec(base64.b64decode(salt))
print(hashlib.md5(bytes(input(), 'utf-8') + salt).hexdigest())

Note that it is not md5 and it does not use a hard coded salt. Based on qwr's solution.