crypto.py

import hashlib
import pyblake2
import axolotl_curve25519 as curve
import base58
import os
from math import log
from operator import xor
from copy import deepcopy
import functools


if bytes == str:  # python2
    str2bytes = lambda s: s
    bytes2str = lambda b: b
    str2list = lambda s: [ord(c) for c in s]
else:  # python3
    str2bytes = lambda s: s.encode('latin-1')
    bytes2str = lambda b: ''.join(map(chr, b))
    str2list = lambda s: [c for c in s]


RoundConstants = [
    0x0000000000000001, 0x0000000000008082, 0x800000000000808A, 0x8000000080008000,
    0x000000000000808B, 0x0000000080000001, 0x8000000080008081, 0x8000000000008009,
    0x000000000000008A, 0x0000000000000088, 0x0000000080008009, 0x000000008000000A,
    0x000000008000808B, 0x800000000000008B, 0x8000000000008089, 0x8000000000008003,
    0x8000000000008002, 0x8000000000000080, 0x000000000000800A, 0x800000008000000A,
    0x8000000080008081, 0x8000000000008080, 0x0000000080000001, 0x8000000080008008
]

RotationConstants = [
    [0, 1, 62, 28, 27, ],
    [36, 44, 6, 55, 20, ],
    [3, 10, 43, 25, 39, ],
    [41, 45, 15, 21, 8, ],
    [18, 2, 61, 56, 14, ]
]

Masks = [(1 << i) - 1 for i in range(65)]


def bits2bytes(x):
    return (int(x) + 7) / 8


def rol(value, left, bits):
    top = value >> (bits - left)
    bot = (value & Masks[bits - left]) << left
    return bot | top

def ror(value, right, bits):
    top = value >> right
    bot = (value & Masks[right]) << (bits - right)
    return bot | top

def multirate_padding(used_bytes, align_bytes):
    padlen = align_bytes - used_bytes
    if padlen == 0:
        padlen = align_bytes
    # note: padding done in 'internal bit ordering', wherein LSB is leftmost
    if padlen == 1:
        return [0x81]
    else:
        return [0x01] + ([0x00] * (int(padlen) - 2)) + [0x80]


def keccak_f(state):
    def round(A, RC):
        W, H = state.W, state.H
        rangeW, rangeH = state.rangeW, state.rangeH
        lanew = state.lanew
        zero = state.zero

        # theta
        C = [functools.reduce(xor, A[x]) for x in rangeW]
        D = [0] * W
        for x in rangeW:
            D[x] = C[(x - 1) % W] ^ rol(C[(x + 1) % W], 1, lanew)
            for y in rangeH:
                A[x][y] ^= D[x]

        # rho and pi
        B = zero()
        for x in rangeW:
            for y in rangeH:
                B[y % W][(2 * x + 3 * y) % H] = rol(A[x][y], RotationConstants[y][x], lanew)

        # chi
        for x in rangeW:
            for y in rangeH:
                A[x][y] = B[x][y] ^ ((~ B[(x + 1) % W][y]) & B[(x + 2) % W][y])

        # iota
        A[0][0] ^= RC

    l = int(log(state.lanew, 2))
    nr = 12 + 2 * l

    for ir in range(nr):
        round(state.s, RoundConstants[ir])


class KeccakState(object):
    W = 5
    H = 5

    rangeW = range(W)
    rangeH = range(H)

    @staticmethod
    def zero():
        return [[0] * KeccakState.W for x in KeccakState.rangeH]

    @staticmethod
    def format(st):
        rows = []

        def fmt(x):
            return '%016x' % x

        for y in KeccakState.rangeH:
            row = []
            for x in rangeW:
                row.append(fmt(st[x][y]))
            rows.append(' '.join(row))
        return '\n'.join(rows)

    @staticmethod
    def lane2bytes(s, w):
        o = []
        for b in range(0, w, 8):
            o.append((s >> b) & 0xff)
        return o

    @staticmethod
    def bytes2lane(bb):
        r = 0
        for b in reversed(bb):
            r = r << 8 | b
        return r

    def __init__(self, bitrate, b):
        self.bitrate = bitrate
        self.b = b

        # only byte-aligned
        assert self.bitrate % 8 == 0
        self.bitrate_bytes = bits2bytes(self.bitrate)

        assert self.b % 25 == 0
        self.lanew = self.b // 25

        self.s = KeccakState.zero()

    def __str__(self):
        return KeccakState.format(self.s)

    def absorb(self, bb):
        assert len(bb) == self.bitrate_bytes

        bb += [0] * int(bits2bytes(self.b - self.bitrate))
        i = 0

        for y in self.rangeH:
            for x in self.rangeW:
                self.s[x][y] ^= KeccakState.bytes2lane(bb[i:i + 8])
                i += 8

    def squeeze(self):
        return self.get_bytes()[:self.bitrate_bytes]

    def get_bytes(self):
        out = [0] * int(bits2bytes(self.b))
        i = 0
        for y in self.rangeH:
            for x in self.rangeW:
                v = KeccakState.lane2bytes(self.s[x][y], self.lanew)
                out[i:i + 8] = v
                i += 8
        return out

    def set_bytes(self, bb):
        i = 0
        for y in self.rangeH:
            for x in self.rangeW:
                self.s[x][y] = KeccakState.bytes2lane(bb[i:i + 8])
                i += 8


class KeccakSponge(object):
    def __init__(self, bitrate, width, padfn, permfn):
        self.state = KeccakState(bitrate, width)
        self.padfn = padfn
        self.permfn = permfn
        self.buffer = []

    def copy(self):
        return deepcopy(self)

    def absorb_block(self, bb):
        self.state.bitrate_bytes = int(self.state.bitrate_bytes)
        assert len(bb) == self.state.bitrate_bytes
        self.state.absorb(bb)
        self.permfn(self.state)

    def absorb(self, s):
        self.buffer = str2list(s)

        while len(self.buffer) >= self.state.bitrate_bytes:
            self.absorb_block(self.buffer[:self.state.bitrate_bytes])
            self.buffer = self.buffer[self.state.bitrate_bytes:]

    def absorb_final(self):
        padded = self.buffer + self.padfn(len(self.buffer), self.state.bitrate_bytes)
        self.absorb_block(padded)
        self.buffer = []

    def squeeze_once(self):
        rc = self.state.squeeze()
        self.permfn(self.state)
        return rc

    def squeeze(self, l):
        Z = self.squeeze_once()
        while len(Z) < l:
            Z += self.squeeze_once()
        return Z[:int(l)]


class KeccakHash(object):
    def __init__(self):
        bitrate_bits = 1088
        capacity_bits = 512
        output_bits = 256
        self.sponge = KeccakSponge(bitrate_bits, bitrate_bits + capacity_bits,
                                   multirate_padding,
                                   keccak_f)
        self.digest_size = bits2bytes(output_bits)
        self.block_size = bits2bytes(bitrate_bits)

    def __repr__(self):
        inf = (self.sponge.state.bitrate,
               self.sponge.state.b - self.sponge.state.bitrate,
               self.digest_size * 8)
        return '<KeccakHash with r=%d, c=%d, image=%d>' % inf

    def digest(self, s):
        self.sponge.absorb(s)
        finalised = self.sponge.copy()
        finalised.absorb_final()
        digest = finalised.squeeze(self.digest_size)
        return ''.join(map(chr, digest))


keccak256 = KeccakHash()

def sha256(s):
    return hashlib.sha256(str2bytes(s)).digest()

def hashChain(s):
    a=pyblake2.blake2b(s, digest_size=32).digest()
    b=keccak256.digest(a)
    return b

def sign(privateKey, message):
    random64 = os.urandom(64)

    return base58.b58encode(curve.calculateSignature(random64, base58.b58decode(privateKey), message))

def id(message):
    return base58.b58encode(hashlib.sha256(message).digest())

def verify_signature(pub_key, message, signature):
    """ all of the arguments are expected in a string format """
    return curve.verifySignature(base58.b58decode(pub_key), message.encode(), base58.b58decode(signature)) == 0