chaCha20.py

import random
import binascii

def plus(x, y):
    return (x + y) & 0xffffffff
    #return (x + y) % 2^32

def lrotate(x, n):
    l = (x << n) & 0xffffffff
    r = (x >> (32-n)) & 0xffffffff
    return l + r

def QuarterRound(a, b, c, d):
    a = plus(a, b); d ^= a; d = lrotate(d, 16)
    c = plus(c, d); b ^= c; b = lrotate(b, 12)
    a = plus(a, b); d ^= a; d = lrotate(d, 8)
    c = plus(c, d); b ^= c; b = lrotate(b, 7)
    return a, b, c, d

def chacha20(text, key, nonce, cnt=0):

    ## initialize ##
    const = [0x64787061, 0x6e642033, 0x322d6279, 0x7465206b,]
    count = [0 + cnt]
    state = const + key + count + nonce

    for _ in range(10):
        # Columns
        state[0], state[4], state[8], state[12] = QuarterRound(state[0], state[4], state[8], state[12])
        state[1], state[5], state[9], state[13] = QuarterRound(state[1], state[5], state[9], state[13])
        state[2], state[6], state[10], state[14] = QuarterRound(state[2], state[6], state[10], state[14])
        state[3], state[7], state[11], state[15] = QuarterRound(state[3], state[7], state[11], state[15])

        # Diagonal
        state[0], state[5], state[10], state[15] = QuarterRound(state[0], state[5], state[10], state[15])
        state[1], state[6], state[11], state[12] = QuarterRound(state[1], state[6], state[11], state[12])
        state[2], state[7], state[8], state[13] = QuarterRound(state[2], state[7], state[8], state[13])
        state[3], state[4], state[9], state[14] = QuarterRound(state[3], state[4], state[9], state[14])

    results = [0]*16
    for i in range(16):
        results[i] = text[i] ^ state[i]

    return results, state

def make_key():
    chrs = "abcdef1234567890"
    key = [0]*8
    for i in range(8):
        k = ""
        for _ in range(8):
            k += chrs[random.randint(0, len(chrs)-1)]
        key[i] = int(k, 16)
    return key


## Test ##
text = [random.randint(114,514)  for _ in range(16)]
print(text)

key = make_key()
nonce = [0, 0, 0]

## Confirmation ##
enc, _ = chacha20(text, nonce, key)
print(enc)

dec, _ = chacha20(enc, nonce, key)
print(dec)
print(text == dec)

poly1305.py

import binascii

bytes_to_int = lambda x:int(binascii.hexlify(x), 16)
str_to_int = lambda x:int(binascii.hexlify(x.encode()), 16)

def make_array(s):
    return [ s[16*i:16*(i+1)] for i in range((len(s)+15)//16) ]

def make_coef(array):
    r = []
    for s in array:
        s = (s << 8) + 1
        len_s = len(bin(s)[2:])
        if len_s < 136:
            s <<= (136-len_s)
        r.append(s)
    return r

def f(coefs, r, s):
    MOD = 2**130 - 5
    x = 0
    for i, Ci in enumerate(coefs[::-1]):
        x += (Ci % MOD)*pow(r, i+1, MOD) % MOD

    return (x + s) & 0xffffffffffffffffffffffffffffffff


text = b"Surely Everyone is someone's HERO"
dt = make_array(text)
dt1 = map(bytes_to_int, dt)

coefs = make_coef(dt1)
r = 114514
s = 364364

x = f(coefs, r, s)
print(x)