# -*- coding: utf-8 -*-
from imports import *
import base64

Sbox = [
	0x63,0x7c,0x77,0x7b,0xf2,0x6b,0x6f,0xc5,0x30,0x01,0x67,0x2b,0xfe,0xd7,0xab,0x76,
	0xca,0x82,0xc9,0x7d,0xfa,0x59,0x47,0xf0,0xad,0xd4,0xa2,0xaf,0x9c,0xa4,0x72,0xc0,
	0xb7,0xfd,0x93,0x26,0x36,0x3f,0xf7,0xcc,0x34,0xa5,0xe5,0xf1,0x71,0xd8,0x31,0x15,
	0x04,0xc7,0x23,0xc3,0x18,0x96,0x05,0x9a,0x07,0x12,0x80,0xe2,0xeb,0x27,0xb2,0x75,
	0x09,0x83,0x2c,0x1a,0x1b,0x6e,0x5a,0xa0,0x52,0x3b,0xd6,0xb3,0x29,0xe3,0x2f,0x84,
	0x53,0xd1,0x00,0xed,0x20,0xfc,0xb1,0x5b,0x6a,0xcb,0xbe,0x39,0x4a,0x4c,0x58,0xcf,
	0xd0,0xef,0xaa,0xfb,0x43,0x4d,0x33,0x85,0x45,0xf9,0x02,0x7f,0x50,0x3c,0x9f,0xa8,
	0x51,0xa3,0x40,0x8f,0x92,0x9d,0x38,0xf5,0xbc,0xb6,0xda,0x21,0x10,0xff,0xf3,0xd2,
	0xcd,0x0c,0x13,0xec,0x5f,0x97,0x44,0x17,0xc4,0xa7,0x7e,0x3d,0x64,0x5d,0x19,0x73,
	0x60,0x81,0x4f,0xdc,0x22,0x2a,0x90,0x88,0x46,0xee,0xb8,0x14,0xde,0x5e,0x0b,0xdb,
	0xe0,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,0xc2,0xd3,0xac,0x62,0x91,0x95,0xe4,0x79,
	0xe7,0xc8,0x37,0x6d,0x8d,0xd5,0x4e,0xa9,0x6c,0x56,0xf4,0xea,0x65,0x7a,0xae,0x08,
	0xba,0x78,0x25,0x2e,0x1c,0xa6,0xb4,0xc6,0xe8,0xdd,0x74,0x1f,0x4b,0xbd,0x8b,0x8a,
	0x70,0x3e,0xb5,0x66,0x48,0x03,0xf6,0x0e,0x61,0x35,0x57,0xb9,0x86,0xc1,0x1d,0x9e,
	0xe1,0xf8,0x98,0x11,0x69,0xd9,0x8e,0x94,0x9b,0x1e,0x87,0xe9,0xce,0x55,0x28,0xdf,
	0x8c,0xa1,0x89,0x0d,0xbf,0xe6,0x42,0x68,0x41,0x99,0x2d,0x0f,0xb0,0x54,0xbb,0x16
]

Rcon = [
	[0x00, 0x00, 0x00, 0x00],
	[0x01, 0x00, 0x00, 0x00],
	[0x02, 0x00, 0x00, 0x00],
	[0x04, 0x00, 0x00, 0x00],
	[0x08, 0x00, 0x00, 0x00],
	[0x10, 0x00, 0x00, 0x00],
	[0x20, 0x00, 0x00, 0x00],
	[0x40, 0x00, 0x00, 0x00],
	[0x80, 0x00, 0x00, 0x00],
	[0x1b, 0x00, 0x00, 0x00],
	[0x36, 0x00, 0x00, 0x00]
]

def Cipher(input, w):
	Nb = 4
	Nr = len(w)/Nb - 1

	state = [ [0] * Nb, [0] * Nb, [0] * Nb, [0] * Nb ]
	for i in range(0, 4*Nb): state[i%4][i//4] = input[i]

	state = AddRoundKey(state, w, 0, Nb)

	for round in range(1, Nr):
		state = SubBytes(state, Nb)
		state = ShiftRows(state, Nb)
		state = MixColumns(state, Nb)
		state = AddRoundKey(state, w, round, Nb)

	state = SubBytes(state, Nb)
	state = ShiftRows(state, Nb)
	state = AddRoundKey(state, w, Nr, Nb)

	output = [0] * 4*Nb
	for i in range(4*Nb): output[i] = state[i%4][i//4]
	return output

def SubBytes(s, Nb):
	for r in range(4):
		for c in range(Nb):
			s[r][c] = Sbox[s[r][c]]
	return s

def ShiftRows(s, Nb):
	t = [0] * 4
	for r in range (1,4):
		for c in range(4): t[c] = s[r][(c+r)%Nb]
		for c in range(4): s[r][c] = t[c]
	return s

def MixColumns(s, Nb):
	for c in range(4):
		a = [0] * 4
		b = [0] * 4
		for i in range(4):
			a[i] = s[i][c]
			b[i] = s[i][c]<<1 ^ 0x011b if s[i][c]&0x80 else s[i][c]<<1
		s[0][c] = b[0] ^ a[1] ^ b[1] ^ a[2] ^ a[3]
		s[1][c] = a[0] ^ b[1] ^ a[2] ^ b[2] ^ a[3]
		s[2][c] = a[0] ^ a[1] ^ b[2] ^ a[3] ^ b[3]
		s[3][c] = a[0] ^ b[0] ^ a[1] ^ a[2] ^ b[3]
	return s

def AddRoundKey(state, w, rnd, Nb):
	for r in range(4):
		for c in range(Nb):
			state[r][c] ^= w[rnd*4+c][r]
	return state

def KeyExpansion(key):
	Nb = 4
	Nk = len(key)/4
	Nr = Nk + 6

	w = [0] * Nb*(Nr+1)
	temp = [0] * 4

	for i in range(Nk):
		r = [key[4*i], key[4*i+1], key[4*i+2], key[4*i+3]]
		w[i] = r

	for i in range(Nk, Nb*(Nr+1)):
		w[i] = [0] * 4
		for t in range(4): temp[t] = w[i-1][t]
		if i%Nk == 0:
			temp = SubWord(RotWord(temp))
			for t in range(4): temp[t] ^= Rcon[i/Nk][t]
		elif Nk>6 and i%Nk == 4:
			temp = SubWord(temp)
		for t in range(4): w[i][t] = w[i-Nk][t] ^ temp[t]
	return w

def SubWord(w):
	for i in range(4): w[i] = Sbox[w[i]]
	return w

def RotWord(w):
	tmp = w[0]
	for i in range(3): w[i] = w[i+1]
	w[3] = tmp
	return w

def encrypt(plaintext, password, nBits):
	blockSize = 16
	if not nBits in (128, 192, 256): return ""
	nBytes = nBits//8
	pwBytes = [0] * nBytes
	for i in range(nBytes): pwBytes[i] = 0 if i>=len(password) else ord(password[i])
	key = Cipher(pwBytes, KeyExpansion(pwBytes))
	key += key[:nBytes-16]

	counterBlock = [0] * blockSize
	now = datetime.datetime.now()
	nonce = mktime( now.timetuple() )*1000 + now.microsecond//1000
	nonceSec = int(nonce // 1000)
	nonceMs  = int(nonce % 1000)

	for i in range(4): counterBlock[i] = urs(nonceSec, i*8) & 0xff
	for i in range(4): counterBlock[i+4] = nonceMs & 0xff

	ctrTxt = ""
	for i in range(8): ctrTxt += chr(counterBlock[i])

	keySchedule = KeyExpansion(key)

	blockCount = int(math.ceil(float(len(plaintext))/float(blockSize)))
	ciphertxt = [0] * blockCount

	for b in range(blockCount):
		for c in range(4): counterBlock[15-c] = urs(b, c*8) & 0xff
		for c in range(4): counterBlock[15-c-4] = urs(b/0x100000000, c*8)

		cipherCntr = Cipher(counterBlock, keySchedule)

		blockLength = blockSize if b<blockCount-1 else (len(plaintext)-1)%blockSize+1
		cipherChar = [0] * blockLength

		for i in range(blockLength):
			cipherChar[i] = cipherCntr[i] ^ ord(plaintext[b*blockSize+i])
			cipherChar[i] = chr( cipherChar[i] )
		ciphertxt[b] = ''.join(cipherChar)

	ciphertext = ctrTxt + ''.join(ciphertxt)
	ciphertext = base64.b64encode(ciphertext)

	return ciphertext

def decrypt(ciphertext, password, nBits):
	blockSize = 16
	if not nBits in (128, 192, 256): return ""
	ciphertext = base64.b64decode(ciphertext)

	nBytes = nBits//8
	pwBytes = [0] * nBytes
	for i in range(nBytes): pwBytes[i] = 0 if i>=len(password) else ord(password[i])
	key = Cipher(pwBytes, KeyExpansion(pwBytes))
	key += key[:nBytes-16]

	counterBlock = [0] * blockSize
	ctrTxt = ciphertext[:8]
	for i in range(8): counterBlock[i] = ord(ctrTxt[i])

	keySchedule = KeyExpansion(key)

	nBlocks = int( math.ceil( float(len(ciphertext)-8) / float(blockSize) ) )
	ct = [0] * nBlocks
	for b in range(nBlocks):
		ct[b] = ciphertext[8+b*blockSize : 8+b*blockSize+blockSize]
	ciphertext = ct

	plaintxt = [0] * len(ciphertext)

	for b in range(nBlocks):
		for c in range(4): counterBlock[15-c] = urs(b, c*8) & 0xff
		for c in range(4): counterBlock[15-c-4] = urs( int( float(b+1)/0x100000000-1 ), c*8) & 0xff

		cipherCntr = Cipher(counterBlock, keySchedule)

		plaintxtByte = [0] * len(ciphertext[b])
		for i in range(len(ciphertext[b])):
			plaintxtByte[i] = cipherCntr[i] ^ ord(ciphertext[b][i])
			plaintxtByte[i] = chr(plaintxtByte[i])
		plaintxt[b] = "".join(plaintxtByte)

	plaintext = "".join(plaintxt)
	return plaintext

def urs(a, b):
	a &= 0xffffffff
	b &= 0x1f
	if a&0x80000000 and b>0:
		a = (a>>1) & 0x7fffffff
		a = a >> (b-1)
	else:
		a = (a >> b)
	return a