def transposition_index_generation(TBOX, j):
'''
Used for transposition of ciphered Bytes among N places
( N - size of secret file ) using TBOX
'''
TIndex = 0
for i in range(0, LT):
TIndex = TIndex << i
TIndex = int(binstr.b_or(bin(TIndex)[2:].zfill(8), TBOX[j][i]), 2)
return TIndex
