sha512.py

import struct
from typing import List
import binascii

from .sha256 import SHA_256
from ..constants import BITS_PER_BYTE, MAX_64_BIT_VALUE


class SHA_512(SHA_256):

    h0 = 0x6a09e667f3bcc908
    h1 = 0xbb67ae8584caa73b
    h2 = 0x3c6ef372fe94f82b
    h3 = 0xa54ff53a5f1d36f1
    h4 = 0x510e527fade682d1
    h5 = 0x9b05688c2b3e6c1f
    h6 = 0x1f83d9abfb41bd6b
    h7 = 0x5be0cd19137e2179

    k = [0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc, 0x3956c25bf348b538,
         0x59f111f1b605d019, 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242, 0x12835b0145706fbe,
         0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
         0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3, 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
         0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, 0x983e5152ee66dfab,
         0xa831c66d2db43210, 0xb00327c898fb213f, 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
         0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed,
         0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6, 0x92722c851482353b,
         0xa2bfe8a14cf10364, 0xa81a664bbc423001, 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
         0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
         0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373,
         0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
         0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915, 0xc67178f2e372532b, 0xca273eceea26619c,
         0xd186b8c721c0c207, 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba, 0x0a637dc5a2c898a6,
         0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
         0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817]

    block_size = 128

    rounds = 80

    @staticmethod
    def right_rotate(n: int, b: int) -> int:
        return ((n >> b) | (n << 64 - b)) & MAX_64_BIT_VALUE

    def cal_padding_length(self, length: int):
        # length + 1 + k congruence 896 mod 1024 adapted to bytes
        return ((112 - (length + 1)) % 128) + BITS_PER_BYTE

    def pad(self, message: bytes) -> bytes:
        length = len(message)
        padding_length = self.cal_padding_length(length)
        padding = b"\x80" + b"\x00" * padding_length
        padded_message = message + padding + struct.pack(">Q", 8 * length)
        return padded_message

    def expand_block(self, block: bytes) -> List[int]:
        w = list(struct.unpack(">16Q", block)) + [0] * (self.rounds - 16)
        for i in range(16, self.rounds):
            s0 = self.right_rotate(
                w[i-15], 1) ^ self.right_rotate(w[i-15], 8) ^ (w[i-15] >> 7)
            s1 = self.right_rotate(
                w[i - 2], 19) ^ self.right_rotate(w[i - 2], 61) ^ (w[i - 2] >> 6)
            w[i] = (w[i-16] + s0 + w[i-7] + s1) & MAX_64_BIT_VALUE
        return w

    def digest(self, message: bytes):
        padded_data = self.pad(message)
        blocks = self.split_into_blocks(padded_data)
        for block in blocks:
            w = self.expand_block(block)
            a, b, c, d, e, f, g, h = self.h0, self.h1, self.h2, self.h3, self.h4, self.h5, self.h6, self.h7
            for i in range(self.rounds):
                S1 = self.right_rotate(e, 14) ^ self.right_rotate(
                    e, 18) ^ self.right_rotate(e, 41)
                ch = (e & f) ^ ((~e) & g)
                temp1 = h + S1 + ch + self.k[i] + w[i]
                S0 = self.right_rotate(a, 28) ^ self.right_rotate(
                    a, 34) ^ self.right_rotate(a, 39)
                maj = (a & b) ^ (a & c) ^ (b & c)
                temp2 = S0 + maj

                h = g
                g = f
                f = e
                e = (d + temp1) & MAX_64_BIT_VALUE
                d = c
                c = b
                b = a
                a = (temp1 + temp2) & MAX_64_BIT_VALUE

            self.h0 = self.h0 + a & MAX_64_BIT_VALUE
            self.h1 = self.h1 + b & MAX_64_BIT_VALUE
            self.h2 = self.h2 + c & MAX_64_BIT_VALUE
            self.h3 = self.h3 + d & MAX_64_BIT_VALUE
            self.h4 = self.h4 + e & MAX_64_BIT_VALUE
            self.h5 = self.h5 + f & MAX_64_BIT_VALUE
            self.h6 = self.h6 + g & MAX_64_BIT_VALUE
            self.h7 = self.h7 + h & MAX_64_BIT_VALUE
        h = (self.h0, self.h1, self.h2, self.h3,
             self.h4, self.h5, self.h6, self.h7)
        return binascii.hexlify(
            b''.join(struct.pack('!Q', e) for e in h),
        ).decode('utf-8')


# TEST USING TEST VECTORS(https://www.di-mgt.com.au/sha_testvectors.html)
if __name__ == "__main__":
    messages = [
        bytes("abc", "utf-8"),
        bytes("", "utf-8"),
        bytes("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", "utf-8"),
        bytes(
            "abcdefghbcdefghicdefghijdefghijkefghijklfghijklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu",
            "utf-8"),
        bytes("a" * 1_000_000, "utf-8"),
    ]
    digests = [
        "ddaf35a193617abacc417349ae20413112e6fa4e89a97ea20a9eeee64b55d39a2192992a274fc1a836ba3c23a3feebbd454d4423643ce80e2a9ac94fa54ca49f",
        "cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e",
        "204a8fc6dda82f0a0ced7beb8e08a41657c16ef468b228a8279be331a703c33596fd15c13b1b07f9aa1d3bea57789ca031ad85c7a71dd70354ec631238ca3445",
        "8e959b75dae313da8cf4f72814fc143f8f7779c6eb9f7fa17299aeadb6889018501d289e4900f7e4331b99dec4b5433ac7d329eeb6dd26545e96e55b874be909",
        "e718483d0ce769644e2e42c7bc15b4638e1f98b13b2044285632a803afa973ebde0ff244877ea60a4cb0432ce577c31beb009c5c2c49aa2e4eadb217ad8cc09b",
    ]
    for m, d in zip(messages, digests):
        sha2_512 = SHA_512()
        digest = sha2_512.digest(m)
        assert (digest == d)