#!/usr/bin/python
import sys

def matmult(a,b):
    zip_b = zip(*b)
    return [[sum(ele_a*ele_b for ele_a, ele_b in zip(row_a, col_b))# % 256
             for col_b in zip_b] for row_a in a]

ROWLEN = 3
KEYLEN = ROWLEN * ROWLEN

KEY_MATRIX = [[-0.0863521, -0.386043, -0.876948], [-0.32937, 0.158125, -0.12726], [0.583477, 0.423473, 0.941312]]

def transposeMatrix(m):
    return map(list,zip(*m))

def getMatrixMinor(m,i,j):
    return [row[:j] + row[j+1:] for row in (m[:i]+m[i+1:])]

def getMatrixDeternminant(m):
    #base case for 2x2 matrix
    if len(m) == 2:
        return m[0][0]*m[1][1]-m[0][1]*m[1][0]

    determinant = 0
    for c in range(len(m)):
        determinant += ((-1)**c)*m[0][c]*getMatrixDeternminant(getMatrixMinor(m,0,c))
    return determinant

def mtx_inv(m):
    determinant = getMatrixDeternminant(m)
    #special case for 2x2 matrix:
    if len(m) == 2:
        return [[m[1][1]/determinant, -1*m[0][1]/determinant],
                [-1*m[1][0]/determinant, m[0][0]/determinant]]

    #find matrix of cofactors
    cofactors = []
    for r in range(len(m)):
        cofactorRow = []
        for c in range(len(m)):
            minor = getMatrixMinor(m,r,c)
            cofactorRow.append(((-1)**(r+c)) * getMatrixDeternminant(minor))
        cofactors.append(cofactorRow)
    cofactors = transposeMatrix(cofactors)
    for r in range(len(cofactors)):
        for c in range(len(cofactors)):
            cofactors[r][c] = cofactors[r][c]/determinant
    return cofactors


def encrypt(f, f2, v):
    print "Plaintext: ", "".join(chr(x) for r in [[0x25, 0x50, 0x44], [0x46, 0x2d, 0x31], [0x2e, v]] for x in r)

    f = f.read()
    if len(f) % KEYLEN:
        f = f + '\x00' * (KEYLEN - len(f) % KEYLEN)

    f_len = len(f)
    plaintext = [[0x25 + 0., 0x50, 0x44], [0x46, 0x2d, 0x31], [0x2e, v, 0x0a]]
    cyphertext = [[0x70, 0xe1, 0xcf], [0x8e, 0x65, 0xc6], [0xc9, 0xd0, 0xe2]]
    X = matmult(mtx_inv(plaintext), cyphertext)
    KEY_MATRIX = mtx_inv(X)
    for i in range(f_len / KEYLEN):
        block = f[i*KEYLEN:(i+1)*KEYLEN]

        matrix = [[0 for j in range(ROWLEN)] for jj in range(ROWLEN)]
        for j in range(ROWLEN):
            for jj in range(ROWLEN):
                matrix[j][jj] = ord(block[j*ROWLEN+jj])
        y = matmult(matrix, KEY_MATRIX)
        if i == 0:
            print(y)
            print(''.join([chr(int(round(item)) % 256) for sublist in y for item in sublist]))
            sys.stdout.flush()
        f2.write(''.join([chr(int(round(item))) for sublist in y for item in sublist]))

if __name__ == "__main__":
    for ver in "1234567":
        f = open(sys.argv[1], "rb")
        f2 = open("try" + ver + ".pdf", "wb")
        encrypt(f, f2, ord(ver))