# -*- coding: utf-8 -*-
# ------------------------------------------------------------
# pelisalacarta 4
# Copyright 2015 tvalacarta@gmail.com
# http://blog.tvalacarta.info/plugin-xbmc/pelisalacarta/
#
# Distributed under the terms of GNU General Public License v3 (GPLv3)
# http://www.gnu.org/licenses/gpl-3.0.html
# ------------------------------------------------------------
# This file is part of pelisalacarta 4.
#
# pelisalacarta 4 is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# pelisalacarta 4 is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with pelisalacarta 4.  If not, see <http://www.gnu.org/licenses/>.
# ------------------------------------------------------------
# AES para Mi tele by Truenon
#------------------------------------------------------------

import datetime
import math
import time


class AES:
    BIT_KEY_128 = 128
    BIT_KEY_192 = 192
    BIT_KEY_256 = 256

    # Sbox is pre-computed multiplicative inverse in GF(2^8) used in subBytes and keyExpansion [§5.1.1]
    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 is Round Constant used for the Key Expansion [1st col is 2^(r-1) in GF(2^8)] [§5.2]
    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 encrypt(self, plaintext, password, nBits):
        blockSize = 16;  # block size fixed at 16 bytes / 128 bits (Nb=4) for AES
        if (not(nBits == self.BIT_KEY_128 or nBits == self.BIT_KEY_192 or nBits == self.BIT_KEY_256)):
                # standard allows 128/192/256 bit keys
                raise Exception("Must be a key mode of either 128, 192, 256 bits")
        
        plaintext = plaintext.encode('utf-8');
        password = password.encode('utf-8');
        
        # use AES itself to encrypt password to get cipher key (using plain password as source for key 
        # expansion) - gives us well encrypted key
        nBytes = nBits / 8  # no bytes in key
        pwBytes = [];
        for i in range(nBytes):
            if((i+1)>len(password)):
                pwBytes.append(0)
            else:
                pwBytes.append(ord(password[i]))
        
        key = self.cipher(pwBytes, self.keyExpansion(pwBytes))  # gives us 16-byte key
        key = key + key[0 : nBytes - 16]  # expand key to 16/24/32 bytes long
        # initialise counter block (NIST SP800-38A §B.2): millisecond time-stamp for nonce in 1st 8 bytes,
        # block counter in 2nd 8 bytes
        counterBlock = [0] * blockSize
        now = datetime.datetime.now()
        nonce = time.mktime( now.timetuple() )*1000 + now.microsecond//1000
        nonceSec = int(nonce // 1000)
        nonceMs  = int(nonce % 1000)
        import random
        nonceRnd = int(random.random()*0xffff)
        
        # encode nonce with seconds in 1st 4 bytes, and (repeated) ms part filling 2nd 4 bytes
        for i in range(2): 
            counterBlock[i] = (self.urs(nonceMs, i*8) & 0xff)
        for i in range(2): 
            counterBlock[i+2] = (self.urs(nonceRnd, i*8) & 0xff)
        for i in range(4): 
            counterBlock[i+4] = (self.urs(nonceSec, i*8) & 0xff)
        # and convert it to a string to go on the front of the ciphertext
        ctrTxt = ''
        for i in range(8): 
            ctrTxt += chr(counterBlock[i])
        
        # generate key schedule - an expansion of the key into distinct Key Rounds for each round
        keySchedule = self.keyExpansion(key)
        blockCount = int(math.ceil(float(len(plaintext)) / float(blockSize)))
        ciphertxt = [0] * blockCount  # ciphertext as array of strings
        
        for b in range(blockCount): 
            # set counter (block #) in last 8 bytes of counter block (leaving nonce in 1st 8 bytes)
            # done in two stages for 32-bit ops: using two words allows us to go past 2^32 blocks (68GB)
            for c in range(4): 
                counterBlock[15 - c] = self.urs(b, c*8) & 0xff
                
            for c in range(4): 
                counterBlock[15 - c - 4] = self.urs(b/0x100000000, c*8)
            
            cipherCntr = self.cipher(counterBlock, keySchedule)  # -- encrypt counter block --
            
            # block size is reduced on final block
            blockLength = 0;
            if(b < blockCount - 1):
                blockLenght = blockSize
            else : 
                blockLenght = (len(plaintext) - 1) % blockSize + 1
                
            cipherChar = [0] * blockLenght
            cipherChar2 = [0] * blockLenght
                    
            for i in range(blockLenght): 
                # -- xor plaintext with ciphered counter char-by-char --
                cipherChar[i] = cipherCntr[i] ^ ord(plaintext[b * blockSize + i])
                cipherChar2[i] = cipherChar[i]
                cipherChar[i] = chr(cipherChar[i])
            ciphertxt[b] = ''.join(cipherChar)
        
                      
        # Array.join is more efficient than repeated string concatenation in IE
        ciphertext = ctrTxt + ''.join(ciphertxt)
        base = Base64() 
        ciphertext = base.encode(ciphertext)
          
        #alert((new Date()) - t);
        return ciphertext
    
    def expires(self):
        future = datetime.datetime.now() + datetime.timedelta(minutes=5)
        return time.mktime(future.timetuple())

    def cipher(self, input, w):    
        # main cipher function [§5.1]
        Nb = 4               #block size (in words): no of columns in state (fixed at 4 for AES)
        Nr = len(w) / Nb - 1 # no of rounds: 10/12/14 for 128/192/256-bit keys
        
        state = [];  # initialise 4xNb byte-array 'state' with input [§3.4]
        i=0
        while i < 4 * Nb :
            y = []
            if(i>3):            
                y = state [i%4]
            y.append(input[i])
            if(i<4):
                state.append(y)    
            #state[i % 4][int(math.floor(i / 4))].append(input[i])
            i = i + 1
             
        state = self.addRoundKey(state, w, 0, Nb)
        
        round = 1
        while round < Nr:
            state = self.subBytes(state, Nb)
            state = self.shiftRows(state, Nb)
            state = self.mixColumns(state)
            state = self.addRoundKey(state, w, round, Nb)
            round = round + 1
        
        state = self.subBytes(state, Nb)
        state = self.shiftRows(state, Nb)
        state = self.addRoundKey(state, w, Nr, Nb)
        
        output = []  # convert state to 1-d array before returning [§3.4]
        for i in range(4 * Nb):
            output.append(state[i % 4][int(math.floor(i / 4))])
        
        return output



    def keyExpansion(self, key): 
        # generate Key Schedule (byte-array Nr+1 x Nb) from Key [§5.2]
        Nb = 4            # block size (in words): no of columns in state (fixed at 4 for AES)
        Nk = len(key) / 4  # key length (in words): 4/6/8 for 128/192/256-bit keys
        Nr = Nk + 6       # no of rounds: 10/12/14 for 128/192/256-bit keys
        
        w = []
        
        for i in range(Nk):
            r = [key[4 * i], key[4 * i + 1], key[4 * i + 2], key[4 * i + 3]]
            w.append(r)
        
        
        i = Nk
        while i < (Nb * (Nr + 1)): 
            temp = []
            for t in range(4):
                temp.append(w[i - 1][t])
            
            
            if (i % Nk == 0):
                temp = self.subWord(self.rotWord(temp))
                for t in range(4):
                    temp[t] ^= self.RCON[i / Nk][t];
            else:
                if (Nk > 6 and i % Nk == 4) :
                        temp = self.subWord(temp)
            
            temp2 = []
            for t in range(4):
                temp2.append(w[i - Nk][t] ^ temp[t]) 
                
            w.append(temp2)
        
            i = i + 1
        
        return w
    


    def subBytes(self, s, Nb):   
        # apply SBox to state S [§5.1.1]
        for r in range(4):
            for c in range(Nb): 
                s[r][c] = self.SBOX[s[r][c]]
        return s
       
    def shiftRows(self,s, Nb):   
        # shift row r of state S left by r bytes [§5.1.2]
        t = [0] * 4
        r=1
        while r<4 :       
            for c in range(4): 
                t[c] = s[r][(c + r) % Nb]  # shift into temp copy            
            for c in range(4): 
                s[r][c] = t[c]         # and copy back
            r = r + 1 # note that this will work for Nb=4,5,6, but not 7,8 (always 4 for AES):
    
        return s;  # see asmaes.sourceforge.net/rijndael/rijndaelImplementation.pdf

    def mixColumns(self,s):  
        # combine bytes of each col of state S [§5.1.3]
        for c in range(4):
            a = []  # 'a' is a copy of the current column from 's'
            b = []  # 'b' is a·{02} in GF(2^8)
            for i in range(4):
                a.append(s[i][c])
                if(s[i][c] & 0x80):
                    b.append(s[i][c] << 1 ^ 0x011b)
                else:
                    b.append(s[i][c] << 1)
            
            # a[n] ^ b[n] is a·{03} in GF(2^8)
            s[0][c] = b[0] ^ a[1] ^ b[1] ^ a[2] ^ a[3] # 2*a0 + 3*a1 + a2 + a3
            s[1][c] = a[0] ^ b[1] ^ a[2] ^ b[2] ^ a[3] # a0 * 2*a1 + 3*a2 + a3
            s[2][c] = a[0] ^ a[1] ^ b[2] ^ a[3] ^ b[3] # a0 + a1 + 2*a2 + 3*a3
            s[3][c] = a[0] ^ b[0] ^ a[1] ^ a[2] ^ b[3] # 3*a0 + a1 + a2 + 2*a3
        return s

    def addRoundKey(self,state, w, rnd, Nb): 
        # xor Round Key into state S [§5.1.4]
        for r in range(4): 
            for c in range(Nb):
                state[r][c] ^= w[rnd * 4 + c][r]       
        return state    
    
    def subWord(self, w):   
        # apply SBox to 4-byte word w
        for i in range(4): 
            w[i] = self.SBOX[w[i]]    
        return w
                
    
    def rotWord(self, w):   
        # rotate 4-byte word w left by one byte
        tmp = w[0]
        for i in range(3): 
            w[i] = w[i + 1]
        w[3] = tmp    
        return w
    def urs(self, 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

class Base64:
    CODE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    
    def encode (self, str) :  # http://tools.ietf.org/html/rfc4648       
                   
        b64 = self.CODE
        plain = str
        pad = ''
        c = len(plain) % 3;  # pad string to length of multiple of 3
        if (c > 0):
            while (c < 3) :
                pad += '=' 
                plain += '\0' 
                c = c + 1
                
        # note: doing padding here saves us doing special-case packing for trailing 1 or 2 chars
        c=0
        e = [0] * int(math.ceil(float(len(plain)) / float(3)))
        while(c<len(plain)): # pack three octets into four hexets
            o1 = ord(plain[c])
            o2 = ord(plain[c+1])
            o3 = ord(plain[c+2])
            bits = o1<<16 | o2<<8 | o3
          
            h1 = bits>>18 & 0x3f
            h2 = bits>>12 & 0x3f
            h3 = bits>>6 & 0x3f
            h4 = bits & 0x3f
        
            # use hextets to index into code string
            e[c/3] = b64[h1] + b64[h2] + b64[h3] + b64[h4]
            
            c = c+3
            
        coded =  ''.join(e)  #join() is far faster than repeated string concatenation in IE
      
        # replace 'A's from padded nulls with '='s
        coded = coded[0 : len(coded)-len(pad)] + pad
       
        return coded
