Алгоритм ГОСТ Р 34.12-2015 «МАГМА»

#!/usr/bin/python2.7
from bitarray import bitarray
from tools import *
import sys
 
def main(msg, key, mode = False):
    bits = read(msg, 64); outbits = bitarray()
    keys = read(key, 32)
    for subbits in bits: outbits.extend(coding(subbits, keys, mode))
    writeBits(outbits)
 
def coding (bits, keys, mode):
    leftBits, rightBits = bits[:32], bits[32:]
    if mode == False:
        for i in range(3):
            for j in range(8):
                rightBits = rightBits ^ keys[j]
                rightBits = replaceS(rightBits)
                rightBits = cycleShift11(rightBits)
                result = leftBits ^ rightBits
                rightBits = leftBits
                leftBits = result
        for j in range(7, -1, -1):
            rightBits = rightBits ^ keys[j]
            rightBits = replaceS(rightBits)
            rightBits = cycleShift11(rightBits)
            result = leftBits ^ rightBits
            if (j != 0):
                rightBits = leftBits
                leftBits = result
            if (j == 0):  rightBits = result
 
    if mode == True:
        for j in range(7, -1, -1):
            rightBits = rightBits ^ keys[j]
            rightBits = replaceS(rightBits)
            rightBits = cycleShift11(rightBits)
            result = leftBits ^ rightBits
            rightBits = leftBits
            leftBits = result
        for i in range(3):
            for j in range(8):
                rightBits = rightBits ^ keys[j]
                rightBits = replaceS(rightBits)
                rightBits = cycleShift11(rightBits)
                result = leftBits ^ rightBits
                if ((i + 2) * (j + 1)) != 32:
                    rightBits = leftBits
                    leftBits = result
                if ((i + 2) * (j + 1)) == 32:
                    rightBits = result
    leftBits.extend(rightBits)
    return leftBits
msg = sys.argv[1]
if sys.argv[2] == '0': mode = False
else: mode = True
main(msg, "key", mode)

from bitarray import bitarray
from math import pow
SBlocks = [[12, 4, 6, 2, 10, 5, 11, 9, 14, 8, 13, 7, 0, 3, 15, 1],
       [6, 8, 2, 3, 9, 10, 5, 12, 1, 14, 4, 7, 11, 13, 0, 15],
       [11, 3, 5, 8, 2, 15, 10, 13, 14, 1, 7, 4, 12, 9, 6, 0],
           [12, 8, 2, 1, 13, 4, 15, 6, 7, 0, 10, 5, 3, 14, 9, 11],
           [7, 15, 5, 10, 8, 1, 6, 13, 0, 9, 3, 14, 11, 4, 2, 12],
       [5, 13, 15, 6, 9, 2, 12, 10, 11, 7, 8, 1, 4, 3, 14, 0],
       [8, 14, 2, 5, 6, 9, 1, 12, 15, 4, 11, 0, 13, 10, 3, 7],
       [1, 7, 14, 13, 0, 5, 8, 3, 4, 15, 10, 6, 9, 12, 11, 2]]
def writeBits(bits):
    bytes = bits.tobytes()
    f = open("newfile", "w")
    f.seek(0); f.write(bytes)
def cycleShift11(bits):
    l = bits[: 11]; r = bits[11: ]
    result = bitarray()
    result.extend(r); result.extend(l)
    return result
def toQuart(bits):
        '''процедура, которая приводит некоторые значения 4-битовых фрагментов в надлежащий вид. Например 0b1 -> 0b0001'''
    pattern = '0000'[len(bits): ]
    result = bitarray(pattern)
    result.extend(bits)
    return result
def replaceS(bits):
    indexes = []
    for i in range(0, len(bits) + 4, 4):
        if i != 0: indexes.append(bit2int(bits[abs(4 - i): i]))
    result, s = bitarray(), bitarray(); k = 0
    for indx in indexes: 
        value = SBlocks[k][indx]
        s = int2bit(value)
        if len(s) < 4: s = toQuart(s)
        result.extend(s)
        k += 1
    return result
def read(path, n):
    '''read for n bits from file'''
    f = open(path); filebits = bitarray(); filebits.fromfile(f)
    bits = []; begin, end = 0, 0
    if len(filebits) == n: bits = [filebits]
    if (len(filebits) % n == 0) and (len(filebits) > n):
        for i in range(0, len(filebits), n):
            begin = i; end = i + n
            bits.append(filebits[begin: end])
    return bits
def int2bit(n):
    sbits = bin(n)[2:]; bits = bitarray()
    for bit in sbits:
        if bit == '1': bits.append(True)
        else: bits.append(False)
    return bits 
def bit2int(bits): return int(bits.to01(), 2)