Advanced Encryption Standard

// Include stdio.h for standard input/output.
// Used for giving output to the screen.
#include<stdio.h>
 
// The number of columns comprising a state in AES. This is a constant in AES. Value=4
#define Nb 4
 
// The number of rounds in AES Cipher. It is simply initiated to zero. The actual value is recieved in the program.
int Nr=0;
 
// The number of 32 bit words in the key. It is simply initiated to zero. The actual value is recieved in the program.
int Nk=0;
 
// in - it is the array that holds the plain text to be encrypted.
// out - it is the array that holds the output CipherText after encryption.
// state - the array that holds the intermediate results during encryption.
unsigned char in[16], out[16], state[4][4];
 
// The array that stores the round keys.
unsigned char RoundKey[240];
 
// The Key input to the AES Program
unsigned char Key[32];
 
int getSBoxValue(int num)
{
    int sbox[256] =   {
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, //0
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, //1
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, //2
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, //3
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, //4
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, //5
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, //6
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, //7
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, //8
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, //9
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, //A
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, //B
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, //C
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, //D
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, //E
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; //F
    return sbox[num];
}
 
// The round constant word array, Rcon[i], contains the values given by 
// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(28)
// Note that i starts at 1, not 0).
int Rcon[255] = {
    0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 
    0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 
    0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 
    0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 
    0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 
    0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 
    0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 
    0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 
    0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 
    0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 
    0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 
    0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 
    0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 
    0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 
    0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 
    0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb  };
 
// This function produces Nb(Nr+1) round keys. The round keys are used in each round to encrypt the states. 
void KeyExpansion()
{
    int i,j;
    unsigned char temp[4],k;
 
    // The first round key is the key itself.
    for(i=0;i<Nk;i++)
    {
        RoundKey[i*4]=Key[i*4];
        RoundKey[i*4+1]=Key[i*4+1];
        RoundKey[i*4+2]=Key[i*4+2];
        RoundKey[i*4+3]=Key[i*4+3];
    }
 
    // All other round keys are found from the previous round keys.
    while (i < (Nb * (Nr+1)))
    {
        for(j=0;j<4;j++)
        {
            temp[j]=RoundKey[(i-1) * 4 + j];
        }
        if (i % Nk == 0)
        {
            // This function rotates the 4 bytes in a word to the left once.
            // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
 
            // Function RotWord()
            {
                k = temp[0];
                temp[0] = temp[1];
                temp[1] = temp[2];
                temp[2] = temp[3];
                temp[3] = k;
            }
 
            // SubWord() is a function that takes a four-byte input word and 
            // applies the S-box to each of the four bytes to produce an output word.
 
            // Function Subword()
            {
                temp[0]=getSBoxValue(temp[0]);
                temp[1]=getSBoxValue(temp[1]);
                temp[2]=getSBoxValue(temp[2]);
                temp[3]=getSBoxValue(temp[3]);
            }
 
            temp[0] =  temp[0] ^ Rcon[i/Nk];
        }
        else if (Nk > 6 && i % Nk == 4)
        {
            // Function Subword()
            {
                temp[0]=getSBoxValue(temp[0]);
                temp[1]=getSBoxValue(temp[1]);
                temp[2]=getSBoxValue(temp[2]);
                temp[3]=getSBoxValue(temp[3]);
            }
        }
        RoundKey[i*4+0] = RoundKey[(i-Nk)*4+0] ^ temp[0];
        RoundKey[i*4+1] = RoundKey[(i-Nk)*4+1] ^ temp[1];
        RoundKey[i*4+2] = RoundKey[(i-Nk)*4+2] ^ temp[2];
        RoundKey[i*4+3] = RoundKey[(i-Nk)*4+3] ^ temp[3];
        i++;
    }
}
 
// This function adds the round key to state.
// The round key is added to the state by an XOR function.
void AddRoundKey(int round) 
{
    int i,j;
    for(i=0;i<4;i++)
    {
        for(j=0;j<4;j++)
        {
            state[j][i] ^= RoundKey[round * Nb * 4 + i * Nb + j];
        }
    }
}
 
// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
void SubBytes()
{
    int i,j;
    for(i=0;i<4;i++)
    {
        for(j=0;j<4;j++)
        {
            state[i][j] = getSBoxValue(state[i][j]);
 
        }
    }
}
 
// The ShiftRows() function shifts the rows in the state to the left.
// Each row is shifted with different offset.
// Offset = Row number. So the first row is not shifted.
void ShiftRows()
{
    unsigned char temp;
 
    // Rotate first row 1 columns to left    
    temp=state[1][0];
    state[1][0]=state[1][1];
    state[1][1]=state[1][2];
    state[1][2]=state[1][3];
    state[1][3]=temp;
 
    // Rotate second row 2 columns to left    
    temp=state[2][0];
    state[2][0]=state[2][2];
    state[2][2]=temp;
 
    temp=state[2][1];
    state[2][1]=state[2][3];
    state[2][3]=temp;
 
    // Rotate third row 3 columns to left
    temp=state[3][0];
    state[3][0]=state[3][3];
    state[3][3]=state[3][2];
    state[3][2]=state[3][1];
    state[3][1]=temp;
}
 
// xtime is a macro that finds the product of {02} and the argument to xtime modulo {1b}  
#define xtime(x)   ((x<<1) ^ (((x>>7) & 1) * 0x1b))
 
// MixColumns function mixes the columns of the state matrix
// The method used may look complicated, but it is easy if you know the underlying theory.
// Refer the documents specified above.
void MixColumns()
{
    int i;
    unsigned char Tmp,Tm,t;
    for(i=0;i<4;i++)
    {    
        t=state[0][i];
        Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ;
        Tm = state[0][i] ^ state[1][i] ; Tm = xtime(Tm); state[0][i] ^= Tm ^ Tmp ;
        Tm = state[1][i] ^ state[2][i] ; Tm = xtime(Tm); state[1][i] ^= Tm ^ Tmp ;
        Tm = state[2][i] ^ state[3][i] ; Tm = xtime(Tm); state[2][i] ^= Tm ^ Tmp ;
        Tm = state[3][i] ^ t ; Tm = xtime(Tm); state[3][i] ^= Tm ^ Tmp ;
    }
}
 
// Cipher is the main function that encrypts the PlainText.
void Cipher()
{
    int i,j,round=0;
 
    //Copy the input PlainText to state array.
    for(i=0;i<4;i++)
    {
        for(j=0;j<4;j++)
        {
            state[j][i] = in[i*4 + j];
        }
    }
 
    // Add the First round key to the state before starting the rounds.
    AddRoundKey(0); 
 
    // There will be Nr rounds.
    // The first Nr-1 rounds are identical.
    // These Nr-1 rounds are executed in the loop below.
    for(round=1;round<Nr;round++)
    {
        SubBytes();
        ShiftRows();
        MixColumns();
        AddRoundKey(round);
    }
 
    // The last round is given below.
    // The MixColumns function is not here in the last round.
    SubBytes();
    ShiftRows();
    AddRoundKey(Nr);
 
    // The encryption process is over.
    // Copy the state array to output array.
    for(i=0;i<4;i++)
    {
        for(j=0;j<4;j++)
        {
            out[i*4+j]=state[j][i];
        }
    }
}
void main()
{
    int i;
 
    // Receive the length of key here.
    while(Nr!=128 && Nr!=192 && Nr!=256)
    {
        printf("Enter the length of Key(128, 192 or 256 only): ");
        scanf("%d",&Nr);
    }
 
    // Calculate Nk and Nr from the received value.
    Nk = Nr / 32;
    Nr = Nk + 6;
 
 
 
// Part 1 is for demonstrative purpose. The key and plaintext are given in the program itself.
//     Part 1: ********************************************************
 
    // The array temp stores the key.
    // The array temp2 stores the plaintext.
    unsigned char temp[16] = {0x00  ,0x01  ,0x02  ,0x03  ,0x04  ,0x05  ,0x06  ,0x07  ,0x08  ,0x09  ,0x0a  ,0x0b  ,0x0c  ,0x0d  ,0x0e  ,0x0f};
    unsigned char temp2[16]= {0x00  ,0x11  ,0x22  ,0x33  ,0x44  ,0x55  ,0x66  ,0x77  ,0x88  ,0x99  ,0xaa  ,0xbb  ,0xcc  ,0xdd  ,0xee  ,0xff};
 
    // Copy the Key and PlainText
    for(i=0;i<Nk*4;i++)
    {
        Key[i]=temp[i];
        in[i]=temp2[i];
    }
 
//           *********************************************************
 
 
 
 
// Uncomment Part 2 if you need to read Key and PlainText from the keyboard.
//     Part 2: ********************************************************
/*
    //Clear the input buffer
    flushall();
 
    //Recieve the Key from the user
    printf("Enter the Key in hexadecimal: ");
    for(i=0;i<Nk*4;i++)
    {
        scanf("%x",&Key[i]);
    }
 
    printf("Enter the PlainText in hexadecimal: ");
    for(i=0;i<Nb*4;i++)
    {
        scanf("%x",&in[i]);
    }
*/
//             ********************************************************
 
 
    // The KeyExpansion routine must be called before encryption.
    KeyExpansion();
 
    // The next function call encrypts the PlainText with the Key using AES algorithm.
    Cipher();
 
    // Output the encrypted text.
    printf("\nText after encryption:\n");
    for(i=0;i<Nk*4;i++)
    {
        printf("%02x ",out[i]);
    }
    printf("\n\n");
}

public class Rijndael{ 
 
 
/** 
 * The S box for Encryption and Encryption key generation 
 */ 
 
 
private final static byte[] S = { 
(byte) 0x63, (byte) 0x7c, (byte) 0x77, (byte) 0x7b, (byte) 0xf2, 
(byte) 0x6b, (byte) 0x6f, (byte) 0xc5, (byte) 0x30, (byte) 0x1, 
(byte) 0x67, (byte) 0x2b, (byte) 0xfe, (byte) 0xd7, (byte) 0xab, 
(byte) 0x76, (byte) 0xca, (byte) 0x82, (byte) 0xc9, (byte) 0x7d, 
(byte) 0xfa, (byte) 0x59, (byte) 0x47, (byte) 0xf0, (byte) 0xad, 
(byte) 0xd4, (byte) 0xa2, (byte) 0xaf, (byte) 0x9c, (byte) 0xa4, 
(byte) 0x72, (byte) 0xc0, (byte) 0xb7, (byte) 0xfd, (byte) 0x93, 
(byte) 0x26, (byte) 0x36, (byte) 0x3f, (byte) 0xf7, (byte) 0xcc, 
(byte) 0x34, (byte) 0xa5, (byte) 0xe5, (byte) 0xf1, (byte) 0x71, 
(byte) 0xd8, (byte) 0x31, (byte) 0x15, (byte) 0x4, (byte) 0xc7, 
(byte) 0x23, (byte) 0xc3, (byte) 0x18, (byte) 0x96, (byte) 0x5, 
(byte) 0x9a, (byte) 0x7, (byte) 0x12, (byte) 0x80, (byte) 0xe2, 
(byte) 0xeb, (byte) 0x27, (byte) 0xb2, (byte) 0x75, (byte) 0x9, 
(byte) 0x83, (byte) 0x2c, (byte) 0x1a, (byte) 0x1b, (byte) 0x6e, 
(byte) 0x5a, (byte) 0xa0, (byte) 0x52, (byte) 0x3b, (byte) 0xd6, 
(byte) 0xb3, (byte) 0x29, (byte) 0xe3, (byte) 0x2f, (byte) 0x84, 
(byte) 0x53, (byte) 0xd1, (byte) 0x0, (byte) 0xed, (byte) 0x20, 
(byte) 0xfc, (byte) 0xb1, (byte) 0x5b, (byte) 0x6a, (byte) 0xcb, 
(byte) 0xbe, (byte) 0x39, (byte) 0x4a, (byte) 0x4c, (byte) 0x58, 
(byte) 0xcf, (byte) 0xd0, (byte) 0xef, (byte) 0xaa, (byte) 0xfb, 
(byte) 0x43, (byte) 0x4d, (byte) 0x33, (byte) 0x85, (byte) 0x45, 
(byte) 0xf9, (byte) 0x2, (byte) 0x7f, (byte) 0x50, (byte) 0x3c, 
(byte) 0x9f, (byte) 0xa8, (byte) 0x51, (byte) 0xa3, (byte) 0x40, 
(byte) 0x8f, (byte) 0x92, (byte) 0x9d, (byte) 0x38, (byte) 0xf5, 
(byte) 0xbc, (byte) 0xb6, (byte) 0xda, (byte) 0x21, (byte) 0x10, 
(byte) 0xff, (byte) 0xf3, (byte) 0xd2, (byte) 0xcd, (byte) 0xc, 
(byte) 0x13, (byte) 0xec, (byte) 0x5f, (byte) 0x97, (byte) 0x44, 
(byte) 0x17, (byte) 0xc4, (byte) 0xa7, (byte) 0x7e, (byte) 0x3d, 
(byte) 0x64, (byte) 0x5d, (byte) 0x19, (byte) 0x73, (byte) 0x60, 
(byte) 0x81, (byte) 0x4f, (byte) 0xdc, (byte) 0x22, (byte) 0x2a, 
(byte) 0x90, (byte) 0x88, (byte) 0x46, (byte) 0xee, (byte) 0xb8, 
(byte) 0x14, (byte) 0xde, (byte) 0x5e, (byte) 0xb, (byte) 0xdb, 
(byte) 0xe0, (byte) 0x32, (byte) 0x3a, (byte) 0xa, (byte) 0x49, 
(byte) 0x6, (byte) 0x24, (byte) 0x5c, (byte) 0xc2, (byte) 0xd3, 
(byte) 0xac, (byte) 0x62, (byte) 0x91, (byte) 0x95, (byte) 0xe4, 
(byte) 0x79, (byte) 0xe7, (byte) 0xc8, (byte) 0x37, (byte) 0x6d, 
(byte) 0x8d, (byte) 0xd5, (byte) 0x4e, (byte) 0xa9, (byte) 0x6c, 
(byte) 0x56, (byte) 0xf4, (byte) 0xea, (byte) 0x65, (byte) 0x7a, 
(byte) 0xae, (byte) 0x8, (byte) 0xba, (byte) 0x78, (byte) 0x25, 
(byte) 0x2e, (byte) 0x1c, (byte) 0xa6, (byte) 0xb4, (byte) 0xc6, 
(byte) 0xe8, (byte) 0xdd, (byte) 0x74, (byte) 0x1f, (byte) 0x4b, 
(byte) 0xbd, (byte) 0x8b, (byte) 0x8a, (byte) 0x70, (byte) 0x3e, 
(byte) 0xb5, (byte) 0x66, (byte) 0x48, (byte) 0x3, (byte) 0xf6, 
(byte) 0xe, (byte) 0x61, (byte) 0x35, (byte) 0x57, (byte) 0xb9, 
(byte) 0x86, (byte) 0xc1, (byte) 0x1d, (byte) 0x9e, (byte) 0xe1, 
(byte) 0xf8, (byte) 0x98, (byte) 0x11, (byte) 0x69, (byte) 0xd9, 
(byte) 0x8e, (byte) 0x94, (byte) 0x9b, (byte) 0x1e, (byte) 0x87, 
(byte) 0xe9, (byte) 0xce, (byte) 0x55, (byte) 0x28, (byte) 0xdf, 
(byte) 0x8c, (byte) 0xa1, (byte) 0x89, (byte) 0xd, (byte) 0xbf, 
(byte) 0xe6, (byte) 0x42, (byte) 0x68, (byte) 0x41, (byte) 0x99, 
(byte) 0x2d, (byte) 0xf, (byte) 0xb0, (byte) 0x54, (byte) 0xbb, 
(byte) 0x16 }; 
 
 
/** 
 * The inverse S box for Decryption and Decryption key generation 
 */ 
 
 
private final static byte[] Si = { 
(byte) 0x52, (byte) 0x9, (byte) 0x6a, (byte) 0xd5, (byte) 0x30, 
(byte) 0x36, (byte) 0xa5, (byte) 0x38, (byte) 0xbf, (byte) 0x40, 
(byte) 0xa3, (byte) 0x9e, (byte) 0x81, (byte) 0xf3, (byte) 0xd7, 
(byte) 0xfb, (byte) 0x7c, (byte) 0xe3, (byte) 0x39, (byte) 0x82, 
(byte) 0x9b, (byte) 0x2f, (byte) 0xff, (byte) 0x87, (byte) 0x34, 
(byte) 0x8e, (byte) 0x43, (byte) 0x44, (byte) 0xc4, (byte) 0xde, 
(byte) 0xe9, (byte) 0xcb, (byte) 0x54, (byte) 0x7b, (byte) 0x94, 
(byte) 0x32, (byte) 0xa6, (byte) 0xc2, (byte) 0x23, (byte) 0x3d, 
(byte) 0xee, (byte) 0x4c, (byte) 0x95, (byte) 0xb, (byte) 0x42, 
(byte) 0xfa, (byte) 0xc3, (byte) 0x4e, (byte) 0x8, (byte) 0x2e, 
(byte) 0xa1, (byte) 0x66, (byte) 0x28, (byte) 0xd9, (byte) 0x24, 
(byte) 0xb2, (byte) 0x76, (byte) 0x5b, (byte) 0xa2, (byte) 0x49, 
(byte) 0x6d, (byte) 0x8b, (byte) 0xd1, (byte) 0x25, (byte) 0x72, 
(byte) 0xf8, (byte) 0xf6, (byte) 0x64, (byte) 0x86, (byte) 0x68, 
(byte) 0x98, (byte) 0x16, (byte) 0xd4, (byte) 0xa4, (byte) 0x5c, 
(byte) 0xcc, (byte) 0x5d, (byte) 0x65, (byte) 0xb6, (byte) 0x92, 
(byte) 0x6c, (byte) 0x70, (byte) 0x48, (byte) 0x50, (byte) 0xfd, 
(byte) 0xed, (byte) 0xb9, (byte) 0xda, (byte) 0x5e, (byte) 0x15, 
(byte) 0x46, (byte) 0x57, (byte) 0xa7, (byte) 0x8d, (byte) 0x9d, 
(byte) 0x84, (byte) 0x90, (byte) 0xd8, (byte) 0xab, (byte) 0x0, 
(byte) 0x8c, (byte) 0xbc, (byte) 0xd3, (byte) 0xa, (byte) 0xf7, 
(byte) 0xe4, (byte) 0x58, (byte) 0x5, (byte) 0xb8, (byte) 0xb3, 
(byte) 0x45, (byte) 0x6, (byte) 0xd0, (byte) 0x2c, (byte) 0x1e, 
(byte) 0x8f, (byte) 0xca, (byte) 0x3f, (byte) 0xf, (byte) 0x2, 
(byte) 0xc1, (byte) 0xaf, (byte) 0xbd, (byte) 0x3, (byte) 0x1, 
(byte) 0x13, (byte) 0x8a, (byte) 0x6b, (byte) 0x3a, (byte) 0x91, 
(byte) 0x11, (byte) 0x41, (byte) 0x4f, (byte) 0x67, (byte) 0xdc, 
(byte) 0xea, (byte) 0x97, (byte) 0xf2, (byte) 0xcf, (byte) 0xce, 
(byte) 0xf0, (byte) 0xb4, (byte) 0xe6, (byte) 0x73, (byte) 0x96, 
(byte) 0xac, (byte) 0x74, (byte) 0x22, (byte) 0xe7, (byte) 0xad, 
(byte) 0x35, (byte) 0x85, (byte) 0xe2, (byte) 0xf9, (byte) 0x37, 
(byte) 0xe8, (byte) 0x1c, (byte) 0x75, (byte) 0xdf, (byte) 0x6e, 
(byte) 0x47, (byte) 0xf1, (byte) 0x1a, (byte) 0x71, (byte) 0x1d, 
(byte) 0x29, (byte) 0xc5, (byte) 0x89, (byte) 0x6f, (byte) 0xb7, 
(byte) 0x62, (byte) 0xe, (byte) 0xaa, (byte) 0x18, (byte) 0xbe, 
(byte) 0x1b, (byte) 0xfc, (byte) 0x56, (byte) 0x3e, (byte) 0x4b, 
(byte) 0xc6, (byte) 0xd2, (byte) 0x79, (byte) 0x20, (byte) 0x9a, 
(byte) 0xdb, (byte) 0xc0, (byte) 0xfe, (byte) 0x78, (byte) 0xcd, 
(byte) 0x5a, (byte) 0xf4, (byte) 0x1f, (byte) 0xdd, (byte) 0xa8, 
(byte) 0x33, (byte) 0x88, (byte) 0x7, (byte) 0xc7, (byte) 0x31, 
(byte) 0xb1, (byte) 0x12, (byte) 0x10, (byte) 0x59, (byte) 0x27, 
(byte) 0x80, (byte) 0xec, (byte) 0x5f, (byte) 0x60, (byte) 0x51, 
(byte) 0x7f, (byte) 0xa9, (byte) 0x19, (byte) 0xb5, (byte) 0x4a, 
(byte) 0xd, (byte) 0x2d, (byte) 0xe5, (byte) 0x7a, (byte) 0x9f, 
(byte) 0x93, (byte) 0xc9, (byte) 0x9c, (byte) 0xef, (byte) 0xa0, 
(byte) 0xe0, (byte) 0x3b, (byte) 0x4d, (byte) 0xae, (byte) 0x2a, 
(byte) 0xf5, (byte) 0xb0, (byte) 0xc8, (byte) 0xeb, (byte) 0xbb, 
(byte) 0x3c, (byte) 0x83, (byte) 0x53, (byte) 0x99, (byte) 0x61, 
(byte) 0x17, (byte) 0x2b, (byte) 0x4, (byte) 0x7e, (byte) 0xba, 
(byte) 0x77, (byte) 0xd6, (byte) 0x26, (byte) 0xe1, (byte) 0x69, 
(byte) 0x14, (byte) 0x63, (byte) 0x55, (byte) 0x21, (byte) 0xc, 
(byte) 0x7d }; 
 
 
/** 
 * The logarithm table for multiplication 
 */ 
 
 
private final static int[] log = { 
 0x0, 0x0, 0x19, 0x1, 0x32, 0x2, 
 0x1a, 0xc6, 0x4b, 0xc7, 0x1b, 0x68, 
 0x33, 0xee, 0xdf, 0x3, 0x64, 0x4, 
 0xe0, 0xe, 0x34, 0x8d, 0x81, 0xef, 
 0x4c, 0x71, 0x8, 0xc8, 0xf8, 0x69, 
 0x1c, 0xc1, 0x7d, 0xc2, 0x1d, 0xb5, 
 0xf9, 0xb9, 0x27, 0x6a, 0x4d, 0xe4, 
 0xa6, 0x72, 0x9a, 0xc9, 0x9, 0x78, 
 0x65, 0x2f, 0x8a, 0x5, 0x21, 0xf, 
 0xe1, 0x24, 0x12, 0xf0, 0x82, 0x45, 
 0x35, 0x93, 0xda, 0x8e, 0x96, 0x8f, 
 0xdb, 0xbd, 0x36, 0xd0, 0xce, 0x94, 
 0x13, 0x5c, 0xd2, 0xf1, 0x40, 0x46, 
 0x83, 0x38, 0x66, 0xdd, 0xfd, 0x30, 
 0xbf, 0x6, 0x8b, 0x62, 0xb3, 0x25, 
 0xe2, 0x98, 0x22, 0x88, 0x91, 0x10, 
 0x7e, 0x6e, 0x48, 0xc3, 0xa3, 0xb6, 
 0x1e, 0x42, 0x3a, 0x6b, 0x28, 0x54, 
 0xfa, 0x85, 0x3d, 0xba, 0x2b, 0x79, 
 0xa, 0x15, 0x9b, 0x9f, 0x5e, 0xca, 
 0x4e, 0xd4, 0xac, 0xe5, 0xf3, 0x73, 
 0xa7, 0x57, 0xaf, 0x58, 0xa8, 0x50, 
 0xf4, 0xea, 0xd6, 0x74, 0x4f, 0xae, 
 0xe9, 0xd5, 0xe7, 0xe6, 0xad, 0xe8, 
 0x2c, 0xd7, 0x75, 0x7a, 0xeb, 0x16, 
 0xb, 0xf5, 0x59, 0xcb, 0x5f, 0xb0, 
 0x9c, 0xa9, 0x51, 0xa0, 0x7f, 0xc, 
 0xf6, 0x6f, 0x17, 0xc4, 0x49, 0xec, 
 0xd8, 0x43, 0x1f, 0x2d, 0xa4, 0x76, 
 0x7b, 0xb7, 0xcc, 0xbb, 0x3e, 0x5a, 
 0xfb, 0x60, 0xb1, 0x86, 0x3b, 0x52, 
 0xa1, 0x6c, 0xaa, 0x55, 0x29, 0x9d, 
 0x97, 0xb2, 0x87, 0x90, 0x61, 0xbe, 
 0xdc, 0xfc, 0xbc, 0x95, 0xcf, 0xcd, 
 0x37, 0x3f, 0x5b, 0xd1, 0x53, 0x39, 
 0x84, 0x3c, 0x41, 0xa2, 0x6d, 0x47, 
 0x14, 0x2a, 0x9e, 0x5d, 0x56, 0xf2, 
 0xd3, 0xab, 0x44, 0x11, 0x92, 0xd9, 
 0x23, 0x20, 0x2e, 0x89, 0xb4, 0x7c, 
 0xb8, 0x26, 0x77, 0x99, 0xe3, 0xa5, 
 0x67, 0x4a, 0xed, 0xde, 0xc5, 0x31, 
 0xfe, 0x18, 0xd, 0x63, 0x8c, 0x80, 
 0xc0, 0xf7, 0x70, 0x7 }; 
 
 
/** 
 * The anti logarithm table for multiplication 
 */ 
private final static int[] alog = { 
 0x1, 0x3, 0x5, 0xf, 0x11, 0x33, 
 0x55, 0xff, 0x1a, 0x2e, 0x72, 0x96, 
 0xa1, 0xf8, 0x13, 0x35, 0x5f, 0xe1, 
 0x38, 0x48, 0xd8, 0x73, 0x95, 0xa4, 
 0xf7, 0x2, 0x6, 0xa, 0x1e, 0x22, 
 0x66, 0xaa, 0xe5, 0x34, 0x5c, 0xe4, 
 0x37, 0x59, 0xeb, 0x26, 0x6a, 0xbe, 
 0xd9, 0x70, 0x90, 0xab, 0xe6, 0x31, 
 0x53, 0xf5, 0x4, 0xc, 0x14, 0x3c, 
 0x44, 0xcc, 0x4f, 0xd1, 0x68, 0xb8, 
 0xd3, 0x6e, 0xb2, 0xcd, 0x4c, 0xd4, 
 0x67, 0xa9, 0xe0, 0x3b, 0x4d, 0xd7, 
 0x62, 0xa6, 0xf1, 0x8, 0x18, 0x28, 
 0x78, 0x88, 0x83, 0x9e, 0xb9, 0xd0, 
 0x6b, 0xbd, 0xdc, 0x7f, 0x81, 0x98, 
 0xb3, 0xce, 0x49, 0xdb, 0x76, 0x9a, 
 0xb5, 0xc4, 0x57, 0xf9, 0x10, 0x30, 
 0x50, 0xf0, 0xb, 0x1d, 0x27, 0x69, 
 0xbb, 0xd6, 0x61, 0xa3, 0xfe, 0x19, 
 0x2b, 0x7d, 0x87, 0x92, 0xad, 0xec, 
 0x2f, 0x71, 0x93, 0xae, 0xe9, 0x20, 
 0x60, 0xa0, 0xfb, 0x16, 0x3a, 0x4e, 
 0xd2, 0x6d, 0xb7, 0xc2, 0x5d, 0xe7, 
 0x32, 0x56, 0xfa, 0x15, 0x3f, 0x41, 
 0xc3, 0x5e, 0xe2, 0x3d, 0x47, 0xc9, 
 0x40, 0xc0, 0x5b, 0xed, 0x2c, 0x74, 
 0x9c, 0xbf, 0xda, 0x75, 0x9f, 0xba, 
 0xd5, 0x64, 0xac, 0xef, 0x2a, 0x7e, 
 0x82, 0x9d, 0xbc, 0xdf, 0x7a, 0x8e, 
 0x89, 0x80, 0x9b, 0xb6, 0xc1, 0x58, 
 0xe8, 0x23, 0x65, 0xaf, 0xea, 0x25, 
 0x6f, 0xb1, 0xc8, 0x43, 0xc5, 0x54, 
 0xfc, 0x1f, 0x21, 0x63, 0xa5, 0xf4, 
 0x7, 0x9, 0x1b, 0x2d, 0x77, 0x99, 
 0xb0, 0xcb, 0x46, 0xca, 0x45, 0xcf, 
 0x4a, 0xde, 0x79, 0x8b, 0x86, 0x91, 
 0xa8, 0xe3, 0x3e, 0x42, 0xc6, 0x51, 
 0xf3, 0xe, 0x12, 0x36, 0x5a, 0xee, 
 0x29, 0x7b, 0x8d, 0x8c, 0x8f, 0x8a, 
 0x85, 0x94, 0xa7, 0xf2, 0xd, 0x17, 
 0x39, 0x4b, 0xdd, 0x7c, 0x84, 0x97, 
 0xa2, 0xfd, 0x1c, 0x24, 0x6c, 0xb4, 
 0xc7, 0x52, 0xf6, 0x1 }; 
 
 
/** 
 * The constants table for key generation 
 */ 
private final static byte[] rcon = { 
(byte) 0x1, (byte) 0x2, (byte) 0x4, (byte) 0x8, (byte) 
0x10, (byte) 0x20, 
(byte) 0x40, (byte) 0x80, (byte) 0x1b, (byte) 0x36, (byte) 
0x6c, (byte) 0xd8, 
(byte) 0xab, (byte) 0x4d, (byte) 0x9a, (byte) 0x2f, (byte) 
0x5e, (byte) 0xbc, 
(byte) 0x63, (byte) 0xc6, (byte) 0x97, (byte) 0x35, (byte) 
0x6a, (byte) 0xd4, 
(byte) 0xb3, (byte) 0x7d, (byte) 0xfa, (byte) 0xef, (byte) 
0xc5, (byte) 0x91 }; 
 
 
/** 
* Returns the product of two binary numbers a and b mod 255 
* <p> 
* 
* @param a operand for multiply. 
* @param b operand for multiply. 
* @return the result of (a * b) % 255. 
*/ 
int mul(int a, int b) { 
        return (a != 0 && b != 0) 
       ? alog[(log[a & 0xFF] + log[b & 0xFF]) % 255] 
        :0; 
          } 
/** 
* implements subBytes transform of Rijndael 
* <p> 
* Substituites for bytes from input array from S-box 
* <p> 
* 
* @param txt the two dimensional byte array in which the bytes need 
to be substituited 
* after the application of this function, txt has new set of values 
*/ 
private void subBytes(byte[][] txt){ 
        for(int i=0;i<4;i++) 
                for(int j =0; j<4;j++) 
                        txt[i][j] = S[txt[i][j] & 0xFF]; 
        }// end subBytes 
 
 
/** 
* implements inverse of subBytes transform of Rijndael, 
* <p> 
* Substituites for bytes from input array from inverse S-box 
* <p> 
* 
* @param txt the two dimensional byte array in which the bytes need 
to be substituited 
* after the application of this function, txt has new set of values 
*/ 
private void invSubBytes(byte[][] txt){ 
        for(int i=0;i<4;i++) 
                for(int j =0; j<4;j++) 
                        txt[i][j] = Si[txt[i][j] & 0xFF]; 
        } 
 
 
/** 
* implements shiftRows transform of Rijndael, 
* <p> 
* Shifts the second, third and fourth rows by one two and three places 
respectively 
* <p> 
* 
* @param txt the two dimensional byte array in which the bytes need 
to be substituited 
* after the application of this function, txt has second, third and 
fourth rows rotated 
*/ 
private void shiftRows(byte[][] txt){ 
        byte[][] tmp = new byte[4][4]; 
        for(int i=0;i<4;i++) 
                for(int j=0;j<4;j++) 
                        tmp[i][j] = txt[i][j]; 
        for(int i=0;i<4;i++) 
                for(int j=0;j<4;j++) 
                        txt[i][j] = tmp[i][(i+j)%4]; 
        } // end shiftRows 
 
 
/** 
* implements inverse shiftRows transform of Rijndael, 
* <p> 
* undoes the shifts in the rows caused by the shiftRows function 
* <p> 
* 
* @param txt the two dimensional byte array in which the bytes need 
to be substituited 
* after the application of this function, txt has second, third and 
fourth rows rotated 
* to obtain original txt array, i.e., was before the application of 
shiftRows tranform 
*/ 
 
 
private void invShiftRows(byte[][] txt){ 
        byte[][] tmp = new byte[4][4]; 
        for(int i=0;i<4;i++) 
                for(int j=0;j<4;j++) 
                        tmp[i][j] = txt[i][j]; 
        for(int i=0;i<4;i++) 
                for(int j=0;j<4;j++) 
                txt[i][(i+j)%4] = tmp[i][j]; 
        } 
 
 
/** 
* implements mixColumns transform of Rijndael 
* <p> 
* xor's columns of txt[][] array with appropriate scheduled keys 
* <p> 
* 
* @param txt the two dimensional byte array in which the rows need 
xor'ed 
* after the application of this function, rows of txt are throroughly 
mixed with 
* appropriate round keys 
*/ 
private void mixColumns(byte[][] txt){ 
        byte[][] tmp = new byte[4][4]; 
        for(int i=0;i<4;i++) 
                for(int j =0; j<4;j++) 
                        tmp[i][j] = txt[i][j]; 
        for(int i =0;i<4;i++){ 
                txt[0][i] = (byte) (mul(2,tmp[0][i]) ^ mul(3,tmp[1][i]) ^ tmp[2][i] 
^ tmp[3][i]); 
                txt[1][i] = (byte) (mul(2,tmp[1][i]) ^ mul(3,tmp[2][i]) ^ tmp[0][i] 
^ tmp[3][i]); 
                txt[2][i] = (byte) (mul(2,tmp[2][i]) ^ mul(3,tmp[3][i]) ^ tmp[1][i] 
^ tmp[0][i]); 
                txt[3][i] = (byte) (mul(2,tmp[3][i]) ^ mul(3,tmp[0][i]) ^ tmp[2][i] 
^ tmp[1][i]); 
                } 
        } 
 
 
/** 
* implements inverse mixColumns transform of Rijndael 
* <p> 
* xor's columns of txt[][] array with appropriate scheduled keys 
* <p> 
* 
* @param txt the two dimensional byte array in which the rows need 
xor'ed 
* after the application of this function, rows of txt are throroughly 
mixed with 
* appropriate round keys 
*/ 
private void invMixColumns(byte[][] txt){ 
        byte[][] tmp = new byte[4][4]; 
        for(int i=0;i<4;i++) 
                for(int j =0; j<4;j++) 
                        tmp[i][j] = txt[i][j]; 
        for(int i =0;i<4;i++){ 
                txt[0][i] = (byte) (mul(0x0E,tmp[0][i]) ^ mul(0x0B,tmp[1][i]) ^ 
mul(0x0D,tmp[2][i]) ^ mul(0x09,tmp[3][i])); 
                txt[1][i] = (byte) (mul(0x09,tmp[0][i]) ^ mul(0x0E,tmp[1][i]) ^ 
mul(0x0B,tmp[2][i]) ^ mul(0x0D,tmp[3][i])); 
                txt[2][i] = (byte) (mul(0x0D,tmp[0][i]) ^ mul(0x09,tmp[1][i]) ^ 
mul(0x0E,tmp[2][i]) ^ mul(0x0B,tmp[3][i])); 
                txt[3][i] = (byte) (mul(0x0B,tmp[0][i]) ^ mul(0x0D,tmp[1][i]) ^ 
mul(0x09,tmp[2][i]) ^ mul(0x0E,tmp[3][i])); 
                } 
        } 
 
 
/** 
* implements Encryption\Decryption key generation algorithm of 
Rijndael 
* <p> 
* generates round keys of each round from an user's input 
* <p> 
* 
* @param key the two integer array supplied by the user 
* after the application of this function, a two dimensional array of 
size 44/4 is generated. 
* @exception java.lang.Exception is thrown when the user supplied 
array has a length other than 16 
*/ 
private byte[][] keySchedule(byte[] key) throws Exception{ 
        if(key.length!=16) throw new Exception("invalid key"); 
        byte[][] w = new byte[44][4]; 
        int i=0; 
        for(i=0;i<4;i++) 
                for(int j=0;j<4;j++) 
                        w[i][j] = key[4*i+j]; 
        byte[] temp = null; 
        for(i = 4;i<44;i++){ 
 
 
        temp = new byte[w[i-1].length]; 
        for(int i2=0;i2<temp.length;i2++) 
                temp[i2] = w[i-1][i2]; 
        // test 
        // System.out.println(printHex(temp)+" : "+i); 
        // end test 
        if (i%4==0){ 
                rotWord(temp); 
        // test 
        //System.out.println(printHex(temp)+" :after rotword "); 
        // end test 
                subWord(temp); 
        // test 
        // System.out.println(printHex(temp)+" :after subword "); 
        // end test 
                temp[0] ^= rcon[(i/4)-1]; 
        // test 
        // if (i%4==0) 
        // System.out.println(printHex(temp)+" : after xor with 
rcon "+rcon[(i/4)-1]); 
        // end test 
                } 
        // test 
        // System.out.println(printHex(w[i-4])+" : w[i-4] w["+(i-4)+"]"); 
        // end test 
                for(int k=0;k<w[i].length;k++) 
                        w[i][k] = (byte) (w[i-4][k] ^ temp[k]); 
        // test 
        // System.out.println(printHex(w[i])+" : w[i]after second 
xor w["+i+"]"); 
        // end test 
                } 
 
 
        return w; 
        } 
 
 
private void addRoundKey(byte[][] txt, byte[][] w, int round){ 
        for(int i=0;i<4;i++) 
                for(int j=0;j<4;j++) 
                        txt[i][j] ^= w[(round*4+j)][i]; 
        } 
 
 
/** 
 * A convenience method for key generation 
 */ 
private void rotWord(byte[] w) throws Exception{ 
        if (w.length!=4) throw new Exception("rotation requires a byte array 
of length 4"); 
        byte temp = w[0]; 
        w[0] = w[1]; 
        w[1] = w[2]; 
        w[2] = w[3]; 
        w[3] = temp; 
        } 
 
 
/** 
 * A convenience method for key generation 
 */ 
private void subWord(byte[] w){ 
        for(int i =0;i<w.length;i++) 
                w[i] = S[w[i] & 0xFF]; 
        } 
 
 
/** 
 * This method encrypts 128 bits (16 bytes) of data and outputs 
corresponding cipher text 
 * @param txt is a 16 byte array given bye user as input, contains 
plain text to be encrypted 
 * @param cpr is a 16 byte array that stores the cipher text output 
 * @param key is a two dimensional byte array, an output of 
keySchedule routine 
 */ 
public void blockEncrypt(byte[] txt, byte[] cpr, byte[][] key){ 
        byte[][] state = new byte[4][4]; 
        for(int i =0;i<4;i++) 
                for(int j=0;j<4;j++) 
                        state[i][j] = txt[i+4*j]; 
        addRoundKey(state,key,0); 
// System.out.println(printHex(txt)); 
// System.out.println(printHex(state)+" : round 0"); 
        for(int i=1;i<=9;i++){ 
                subBytes(state); 
// System.out.println(printHex(state)+" : round "+i+" : after 
subBytes"); 
                shiftRows(state); 
// System.out.println(printHex(state)+" : round "+i+" : after 
shiftRows"); 
                mixColumns(state); 
// System.out.println(printHex(state)+" : round "+i+" : after 
mixColumns"); 
                addRoundKey(state,key,i); 
                } 
        subBytes(state); 
        shiftRows(state); 
        addRoundKey(state,key,10); 
        for(int j=0;j<4;j++) 
                for(int l=0;