#include "./aes.h"

#include <cstring>

namespace Crypto {

 Aes::byte Aes::sbox[16][16] = {
     { 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 }
 };

 Aes::byte Aes::inv_sbox[16][16] = {
     { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb },
     { 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb },
     { 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e },
     { 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25 },
     { 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92 },
     { 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84 },
     { 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06 },
     { 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b },
     { 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73 },
     { 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e },
     { 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b },
     { 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4 },
     { 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f },
     { 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef },
     { 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61 },
     { 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d }
 };

 Aes::word Aes::rcon[52] = {
     0x00000000, 0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000, 0x40000000,
     0x80000000, 0x1B000000, 0x36000000, 0x6C000000, 0xD8000000, 0xAB000000, 0x4D000000, 0x9A000000,
     0x2F000000, 0x5E000000, 0xBC000000, 0x63000000, 0xC6000000, 0x97000000, 0x35000000, 0x6A000000,
     0xD4000000, 0xB3000000, 0x7D000000, 0xFA000000, 0xEF000000, 0xC5000000, 0x91000000, 0x39000000,
     0x72000000, 0xE4000000, 0xD3000000, 0xBD000000, 0x61000000, 0xC2000000, 0x9F000000, 0x25000000,
     0x4A000000, 0x94000000, 0x33000000, 0x66000000, 0xCC000000, 0x83000000, 0x1D000000, 0x3A000000,
     0x74000000, 0xE8000000, 0xCB000000, 0x8D000000
 };

 Aes::Aes() :
     key_length(0),
     num_rounds(0),
     w(0)
 {
     memset(state, 0, 16);
 }

 Aes::~Aes()
 {
 }

 Aes::byte Aes::gmul(byte a, byte b)
 {
     unsigned char p = 0;
     unsigned char hi;

     for(byte i = 0; i < 8; ++i) {
         if((b & 1) == 1)
             p ^= a;
         hi = (a & 0x80);
         a <<= 1;
         if(hi == 0x80)
             a ^= 0x1b;
         b >>= 1;
     }
     return p;
 }

void Aes::rotWord(word *b)
 {
     byte tmp[4];
     memcpy(tmp, b, 4);

     byte tmpb = tmp[3];

     for(byte i = 3; i > 0; --i)
         tmp[i] = tmp[i - 1];

     tmp[0] = tmpb;

     memcpy(b, tmp, 4);
 }

void Aes::subWord( word *b )
 {
     byte tmp[ 4 ];
     memcpy( tmp, b, 4 );

     for( byte i = 0; i < 4; ++i )
         tmp[ i ] = sbox[ tmp[ i ] >> 4 ][ tmp[ i ] & 0x0f ];

     memcpy( b, tmp, 4 );
 }

void Aes::expandKey( byte *key )
 {
     if( w )
         delete [] w;

     w = new word[ 4 * ( num_rounds + 1 ) ];

     for( byte iw = 0, ib = 0; iw < key_length; ++iw, ib += 4 )
         w[ iw ] = ( key[ ib ] << 24 ) + ( key[ ib + 1 ] << 16 ) + ( key[ ib + 2 ] << 8 ) + key[ ib + 3 ];

     word tmp;

     for( byte i = key_length; i < ( 4 * ( num_rounds + 1 ) ); ++i ) {

         tmp = w[ i - 1 ];

         if( ( i % key_length ) == 0 ) {
             rotWord( &tmp );
             subWord( &tmp );
             tmp ^= rcon[ i / key_length ];
         } else if( ( key_length > 6 ) && ( ( i % key_length ) == 4 ) ) {
             subWord( &tmp );
         }

         w[ i ] = w[ i - key_length ] ^ tmp;
     }
 }

void Aes::addRoundKey( byte round )
 {
     for( byte col = 0; col < 4; ++col )
         for( byte row = 0; row < 4; ++row )
             state[ row ][ col ] ^= ( w[ round * 4 + col ] >> ( 24 - row * 8 ) ) & 0x000000ff;
 }

void Aes::shiftRows( void )
 {
     byte tmp = 0;
     tmp = state[ 1 ][ 0 ];
     state[ 1 ][ 0 ] = state[ 1 ][ 1 ];
     state[ 1 ][ 1 ] = state[ 1 ][ 2 ];
     state[ 1 ][ 2 ] = state[ 1 ][ 3 ];
     state[ 1 ][ 3 ] = tmp;

     tmp = state[ 2 ][ 0 ];
     state[ 2 ][ 0 ] = state[ 2 ][ 2 ];
     state[ 2 ][ 2 ] = tmp;
     tmp = state[ 2 ][ 1 ];
     state[ 2 ][ 1 ] = state[ 2 ][ 3 ];
     state[ 2 ][ 3 ] = tmp;

     tmp = state[ 3 ][ 3 ];
     state[ 3 ][ 3 ] = state[ 3 ][ 2 ];
     state[ 3 ][ 2 ] = state[ 3 ][ 1 ];
     state[ 3 ][ 1 ] = state[ 3 ][ 0 ];
     state[ 3 ][ 0 ] = tmp;
 }

void Aes::invShiftRows( void )
 {
     byte tmp = 0;
     tmp = state[ 3 ][ 0 ];
     state[ 3 ][ 0 ] = state[ 3 ][ 1 ];
     state[ 3 ][ 1 ] = state[ 3 ][ 2 ];
     state[ 3 ][ 2 ] = state[ 3 ][ 3 ];
     state[ 3 ][ 3 ] = tmp;

     tmp = state[ 2 ][ 0 ];
     state[ 2 ][ 0 ] = state[ 2 ][ 2 ];
     state[ 2 ][ 2 ] = tmp;
     tmp = state[ 2 ][ 1 ];
     state[ 2 ][ 1 ] = state[ 2 ][ 3 ];
     state[ 2 ][ 3 ] = tmp;

     tmp = state[ 1 ][ 3 ];
     state[ 1 ][ 3 ] = state[ 1 ][ 2 ];
     state[ 1 ][ 2 ] = state[ 1 ][ 1 ];
     state[ 1 ][ 1 ] = state[ 1 ][ 0 ];
     state[ 1 ][ 0 ] = tmp;
 }

void Aes::mixColumns( void )
 {
     unsigned char a[4];
     unsigned char b[4];
     unsigned char h = 0;

     for( byte col = 0; col < 4; ++col ) {

         for( byte row = 0; row < 4; ++row ) {

             a[ row ]    = state[ row ][ col ];
             h            = state[ row ][ col ] & 0x80;
             b[ row ]    = state[ row ][ col ] << 1;

             if( h == 0x80 )
                 b[ row ] ^= 0x1b;
         }

         state[ 0 ][ col ] = b[ 0 ] ^ a[ 3 ] ^ a[ 2 ] ^ b[ 1 ] ^ a[ 1 ];
         state[ 1 ][ col ] = b[ 1 ] ^ a[ 0 ] ^ a[ 3 ] ^ b[ 2 ] ^ a[ 2 ];
         state[ 2 ][ col ] = b[ 2 ] ^ a[ 1 ] ^ a[ 0 ] ^ b[ 3 ] ^ a[ 3 ];
         state[ 3 ][ col ] = b[ 3 ] ^ a[ 2 ] ^ a[ 1 ] ^ b[ 0 ] ^ a[ 0 ];
     }
 }

void Aes::invMixColumns( void )
 {
     unsigned char a[4];

     for( byte col = 0; col < 4; ++col ) {

         for( byte row = 0; row < 4; ++ row )
             a[ row ] = state[ row ][ col ];

         state[ 0 ][ col ] = gmul( a[ 0 ], 14 ) ^ gmul( a[ 3 ], 9 ) ^ gmul( a[ 2 ], 13 ) ^ gmul( a[ 1 ], 11 );
         state[ 1 ][ col ] = gmul( a[ 1 ], 14 ) ^ gmul( a[ 0 ], 9 ) ^ gmul( a[ 3 ], 13 ) ^ gmul( a[ 2 ], 11 );
         state[ 2 ][ col ] = gmul( a[ 2 ], 14 ) ^ gmul( a[ 1 ], 9 ) ^ gmul( a[ 0 ], 13 ) ^ gmul( a[ 3 ], 11 );
         state[ 3 ][ col ] = gmul( a[ 3 ], 14 ) ^ gmul( a[ 2 ], 9 ) ^ gmul( a[ 1 ], 13 ) ^ gmul( a[ 0 ], 11 );
     }

 }

bool Aes::setKey( char *key )
 {

     size_t key_len = strlen( key );

     byte *w_key            = 0;
     byte des_key_len    = 0;

     if( key_len <= 16 ) {

         key_length = 4;
         num_rounds = 10;
         des_key_len = 16;

     } else if( key_len <= 24 ) {

         key_length = 6;
         num_rounds = 12;
         des_key_len = 24;

     } else if( key_len <= 32 ) {

         key_length = 8;
         num_rounds = 14;
         des_key_len = 32;

     }

     w_key = new byte[ des_key_len ];

     for( byte i = 0, t = 0; t < des_key_len; ++i, ++t ) {
         if( i == key_len )
             i = 0;
         *( w_key + t ) = *( key + i );
     }

     expandKey( w_key );

     delete [] w_key;

     return true;
 }

void Aes::cipher( void )
 {
     addRoundKey( 0 );

     for( byte round = 1; round < num_rounds; ++round ) {

         for( byte row = 0; row < 4; ++row )
             for( byte col = 0; col < 4; ++col )
                 state[ row ][ col ] = sbox[ state[ row ][ col ] >> 4 ][ state[ row ][ col ] & 0x0f ];

         shiftRows( );
         mixColumns( );
         addRoundKey( round );
     }

     for( byte row = 0; row < 4; ++row )
         for( byte col = 0; col < 4; ++col )
             state[ row ][ col ] = sbox[ state[ row ][ col ] >> 4 ][ state[ row ][ col ] & 0x0f ];

     shiftRows( );
     addRoundKey( num_rounds );
 }

void Aes::invCipher( void )
 {
     addRoundKey( num_rounds );

     for( byte round = ( num_rounds - 1 ); round > 0; --round ) {

         invShiftRows( );

         for( byte row = 0; row < 4; ++row )
             for( byte col = 0; col < 4; ++col )
                 state[ row ][ col ] = inv_sbox[ state[ row ][ col ] >> 4 ][ state[ row ][ col ] & 0x0f ];

         addRoundKey( round );
         invMixColumns( );
     }

     invShiftRows( );

     for( byte row = 0; row < 4; ++row )
         for( byte col = 0; col < 4; ++col )
             state[ row ][ col ] = inv_sbox[ state[ row ][ col ] >> 4 ][ state[ row ][ col ] & 0x0f ];

     addRoundKey( 0 );
 }

 size_t Aes::encrypt( char **data, size_t length, char *key )
 {
     if( length == 0 )
         return 0;

     if( !setKey( key ) )
         return 0;

     size_t old_length = length;
     while( length % 16 )
         ++length;

     char *buffer = new char[ length ];
     memset( buffer, 0, length );
     memcpy( buffer, *data, old_length );

     delete [] *data;
     *data = buffer;

     size_t cur_block = 0;

     do {

         for( byte col = 0; col < 4; ++col )
             for( byte row = 0; row < 4; ++row )
                 state[ row ][ col ] = static_cast< byte >( ( *data )[ cur_block * 16 + row + 4 * col ] );

         cipher( );

         for( byte col = 0; col < 4; ++col )
             for( byte row = 0; row < 4; ++row )
                 ( *data )[ cur_block * 16 + row + 4 * col ] = static_cast< char >( state[ row ][ col ] );

         ++cur_block;

     } while( cur_block * 16 != length );

     return cur_block;
 }

 size_t Aes::decrypt( char **data, size_t length, char *key )
 {
     if( length == 0 )
         return 0;

     if( !setKey( key ) )
         return 0;

     size_t old_length = length;
     while( length % 16 )
         ++length;

     char *buffer = new char[ length ];
     memset( buffer, 0, length );
     memcpy( buffer, *data, old_length );

     delete [] *data;
     *data = buffer;

     size_t cur_block = 0;

     do {

         for( byte col = 0; col < 4; ++col )
             for( byte row = 0; row < 4; ++row )
                 state[ row ][ col ] = static_cast< byte >( ( *data )[ cur_block * 16 + row + 4 * col ] );

         invCipher( );

         for( byte col = 0; col < 4; ++col )
             for( byte row = 0; row < 4; ++row )
                 ( *data )[ cur_block * 16 + row + 4 * col ] = static_cast< char >( state[ row ][ col ] );

         ++cur_block;

     } while( cur_block * 16 != length );

     --length;

     while( ! ( ( *buffer ) + length ) )
         --length;

     ++length;

     return length;
 }

}