def Encrypt(k, S, SE, SBOX, TBOX, IndexArray, SrtB):
E = ['' for i in range(4)]
for i in range(0, LT - 1):
for j in range(0, LT):
E[j] = binstr.b_xor(W[j], S[j])
for j in range(0, LT):
if (EvenParity(E[j]) == True):
Rotate_Right(j, SBOX)
else:
Rotate_Left(j, SBOX)
SBOX[2][j] = binstr.b_xor(SBOX[2][j], bin(SrtB[j])[2:].zfill(8))
Transpose(SBOX)
E = [str(x) for x in numpy.roll(E, 1)]
for i in range(0, LT):
TIndex = transposition_index_generation(TBOX, i)
#if k==0:
# print "E:",TIndex
while (IndexArray[TIndex % N] != 0):
TIndex = TIndex + 1
TIndex = TIndex % N
#if k==0:
# print TIndex
# print "E[i] {}".format(int(E[i],2))
#write E[i] in encrypted file SE in position of TIndex
SE[TIndex] = int(E[i], 2)
IndexArray[TIndex] = 1
SrtB[i] = int(S[i], 2)
SBOX, TBOX = TBOX, SBOX
#if k==0:
# print " E \n SBOX {}\n TBOX {}".format(SBOX,TBOX)
return SE, SBOX, TBOX
def encryption_key_gen(EKy, Ky, D):
'''
Generates 32 Bytes EKy from user input Ky ( >= 16 Bytes )
and D ( MD5 hash of Ky = 16 Bytes )
'''
p1 = p2 = p3 = 0
L1 = len(Ky)
for i in range(0, 32):
if(i % 2 == 0):
Eky[i] = D[p1]
p1 += 1
else:
p4 = p2 + 1
Eky[i] = binstr.b_xor(binstr.b_xor(D[p2], D[p4]), Ky[(p3) % L1])
p3 += 1
return Eky
def WORD_generation(SBOX, W):
'''
Generates of 1 x LT WORD array by column wise XORing of SBOX
( used for encryption )
'''
for i in range(0, LT):
for j in range(0, LT):
W[i] = binstr.b_xor(W[i], SBOX[j][i])
def Decrypt(SE_N, front_index, SE, SD, SBOX, TBOX, IndexArray, SrtB):
E = ['' for i in range(4)]
S = ['' for i in range(4)]
for i in range(0, LT):
TIndex = transposition_index_generation(TBOX, i)
while(IndexArray[TIndex % N] != 0):
TIndex = TIndex + 1
TIndex = TIndex % N
#print i, TIndex, len(SE)
#write E[i] in encrypted file SE in position of TIndex
E[i] = SE_N[TIndex]
#print "E[i] {}".format(E[i])
IndexArray[TIndex] = 1
E = [str(x) for x in numpy.roll(E, -1)]
for i in range(0, LT - 1):
for j in range(0, LT):
S[j] = binstr.b_xor(W[j],E[j])
# print "S[j] {} W[j] {} E[j] {}".format(S[j],W[j],E[j])
for j in range(0, LT):
if(EvenParity(E[j]) == True):
Rotate_Right(j, SBOX)
else:
Rotate_Left(j, SBOX)
SBOX[2][j] = binstr.b_xor(SBOX[2][j], bin(SrtB[j])[2:].zfill(8))
Transpose(SBOX)
for i in range(LT):
# print i,S[i]
SD[front_index+i] = int(S[i],2)
SrtB[i] = int(S[i],2)
SBOX, TBOX = TBOX, SBOX
# print "D \n SBOX {}\n TBOX {}".format(SBOX,TBOX)
return SD, SBOX, TBOX