aes.java

Advanced Encrypt Algorithm (AES) is a symetric method to crypt message or document

package aes;

public class AES {

    
    
    private static byte[] RC = {(byte)1,(byte)2,(byte)4,(byte)8,(byte)16,(byte)32,(byte)64,(byte)128,(byte)27,
		                    (byte)54,(byte)108,(byte)216,(byte)171,(byte)77,(byte)154,(byte)47,(byte)94,
				    (byte)188,(byte)99,(byte)198,(byte)151,(byte)53,(byte)106,(byte)212,(byte)179,
				    (byte)125};
    private static byte Nb=4;
    private static byte Nk=4;
    private static byte Nr=10;
    public static byte Nb4=(byte)(Nb<<2);
    private static byte Nk4=(byte)(Nk<<2);
    private static byte[] key =new byte [Nb4*(Nr+1)];
    public AES(String cle) {
            byte[] cipherkey=new byte[Nk4];
            for(int i=0;i<Nk4;i++)cipherkey[i]=(byte)Integer.parseInt(cle.substring((i<<1),((i+1)<<1)), 16);
            for(int i=0;i<256;i++)invsbox[sbox[i] & 0xFF]=(byte)i;
	    GenerateKey (cipherkey, Nk, Nr);
    }

    private static byte[] sbox ={     
        (byte)0x63, (byte)0x7c, (byte)0x77, (byte)0x7b, (byte)0xf2, (byte)0x6b, (byte)0x6f, (byte)0xc5, 
        (byte)0x30, (byte)0x01, (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)0x04, (byte)0xc7, (byte)0x23, (byte)0xc3, (byte)0x18, (byte)0x96, (byte)0x05, (byte)0x9a, 
        (byte)0x07, (byte)0x12, (byte)0x80, (byte)0xe2, (byte)0xeb, (byte)0x27, (byte)0xb2, (byte)0x75,
        (byte)0x09, (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)0x00, (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)0x02, (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)0x0c, (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)0x0b, (byte)0xdb,
        (byte)0xe0, (byte)0x32, (byte)0x3a, (byte)0x0a, (byte)0x49, (byte)0x06, (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)0x08,
        (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)0x03, (byte)0xf6, (byte)0x0e, 
        (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)0x0d, (byte)0xbf, (byte)0xe6, (byte)0x42, (byte)0x68, 
        (byte)0x41, (byte)0x99, (byte)0x2d, (byte)0x0f, (byte)0xb0, (byte)0x54, (byte)0xbb, (byte)0x16
    };

    public static byte[] invsbox =new byte[256];
    
    private static void ByteSub (byte[] state)
    {	
            for (byte i = 0; i<Nb4; i++)state[i] = sbox[state[i] & 0xFF];
    }

    private static byte ByteSub (byte inputbyte) 		
    {    
           return sbox[inputbyte & 0xFF];
    }

    public static void InvByteSub (byte[] state)
    {
            for (byte i = 0; i<Nb4; i++)state[i] = invsbox[state[i] & 0xFF];
    }

    private static void ShiftRow(byte[] state)	
    {
            byte[] temp = new byte [2];
            temp[0] = state[1];
            for(byte i = 1; i<10; i+=4)
            {
                    state[i] = state[i+4];
            }
            state[13] = temp[0];
            temp[0] = state[2];
            temp[1] = state[6];
            for(byte j = 2; j<7; j+=4)
            {
                    state[j] = state[j+8];
            }
            state[10] = temp[0];
            state[14] = temp[1];
            temp[0] = state[15];
            for(byte k = 15; k>6; k-=4)
            {
                    state[k] = state[k-4];
            }
            state[3] = temp[0];
    }

    private static void InvShiftRow (byte[] state)
    {
            byte[] temp = new byte[2];
            temp[0] = state[13];
            for(byte i=13; i>4; i-=4)
            {
                    state[i]=state[i-4];
            }
            state[1] = temp[0];
            temp[0] = state[2];
            temp[1] = state[6];
            for(byte j=2; j<7; j+=4)
            {
                    state[j] = state[j+8];
            }
            state[10]=temp[0];
            state[14]=temp[1];
            temp[0] = state[3];
            for(byte k=3; k<12; k+=4)
            {
                    state[k] = state[k+4];
            }
            state[15] = temp[0];
    }

    private static void MixColumn (byte[] state)
    {
            byte[] temp = new byte[Nb4];
            for(byte i = 0; i<Nb4; i++)temp[i] = state[i];
            for(byte k=0; k<Nb4; k+=4)
            {
                    state[0+k] = (byte) ( XTime(temp[0+k]) ^ temp[3+k] ^ temp[2+k] ^ Time3(temp[1+k])    );
                    state[1+k] = (byte) ( XTime(temp[1+k]) ^ temp[0+k] ^ temp[3+k] ^ Time3(temp[2+k])   );
                    state[2+k] = (byte) ( XTime(temp[2+k]) ^ temp[1+k] ^ temp[0+k] ^ Time3(temp[3+k]) );
                    state[3+k] = (byte) ( XTime(temp[3+k]) ^ temp[2+k] ^ temp[1+k] ^ Time3(temp[0+k]) );
            }
    }

    private static void InvMixColumn (byte[] state)
    {
            byte[] temp = new byte[Nb4];
            for(byte i = 0; i<Nb4; i++)temp[i] = state[i];
            for(byte k=0; k<Nb4; k+=4)
            {
                    state[0+k] = (byte) ( TimeE(temp[0+k]) ^ Time9(temp[3+k])  ^ TimeD(temp[2+k]) ^ TimeB(temp[1+k])  );
                    state[1+k] = (byte) ( TimeE(temp[1+k]) ^ Time9(temp[0+k]) ^ TimeD(temp[3+k]) ^   TimeB(temp[2+k])   );
                    state[2+k] = (byte) ( TimeE(temp[2+k]) ^ Time9(temp[1+k]) ^ TimeD(temp[0+k]) ^   TimeB(temp[3+k]) );
                    state[3+k] = (byte) ( TimeE(temp[3+k]) ^ Time9(temp[2+k]) ^ TimeD(temp[1+k]) ^   TimeB(temp[0+k])     );
            }



    }

    private static byte XTime (byte Tm)
    {
            byte temp = Tm;
            temp &= (byte)0x80;
            Tm <<= 1;
            if (temp == (byte)0x80)
            {
                    Tm ^= (byte)(0x1b);
            }
            return Tm;
    }
    
    private static byte Time3 (byte Tm){
        byte a=Tm;
        Tm=(byte)(Tm^XTime(a));
        return Tm;
        
    }
    
    private static byte Time9 (byte Tm){
        byte a=Tm;
        Tm=(byte)(Tm^XTime(XTime(XTime(a))));
        return Tm;
        
    }
    
    private static byte TimeE (byte Tm){
        
        byte a=XTime(Tm);
        Tm=a;
        a=XTime(a);
        Tm^=a;
        Tm^=XTime(a);
        
        return Tm;
        
    }
    
    private static byte TimeD (byte Tm){
        byte a=Tm;
        a=XTime(XTime(a));
        Tm^=a;
        Tm^=XTime(a);
        return Tm;
        
    }
    
    private static byte TimeB (byte Tm){
        byte a=Tm;
        a=XTime(a);
        Tm^=a;
        Tm^=XTime(XTime(a));
        return Tm;
        
    }
   
    private static void AddRoundKey (byte[] state,byte current_round)
    {
            short count = (short) (current_round<<4);
            for(byte i = 0; i<16; i++)
            {
                    state[i] ^= key[count++];
            }
    }

    private static void GenerateKey (byte[] cipherkey, byte Nk, byte Nr)
    {
            short i;
            for( i = (short)(0); i < (short)( Nk<<2 ); i++)
            {
                    key[i] = cipherkey[i];
            }

            byte[] temp = new byte[4];
            byte temp2;			
            byte count = (byte)0;
            for ( i = (short)((Nk*4) - 4) ; i < (short)(4*Nk * (Nr + 1) - 4) ; i += 4 )	
            {
                    for (byte j = 0; j<4; j++)
                    {
                            temp[j] = key[i++];
                    }
                    if ( ( (i/4) % Nk ) == 0 )
                    {
                            temp2 = temp[0];
                            for (byte k = 0; k<3; k++)
                            {
                                    temp[k] = temp [ (k+1)%4 ];
                            }
                            temp[3] = temp2;
                            for (byte ctr = 0; ctr<4; ctr++)
                            {
                                    temp[ctr] = ByteSub(temp[ctr]);
                            }
                            temp[0] ^= RC[count++];
                    }

                    else if ( ( Nk >6 ) && ( ( (i/4) % Nk ) == 4) )
                    {
                            for (byte ctr2 = 0; ctr2 < 4; ctr2++)
                            {
                                    temp[ctr2] = ByteSub(temp[ctr2]);
                            }
                    }
                    for (byte ctr3 = 0; ctr3 < 4; ctr3++)
                    {
                        key[i] = (byte) ( key[ i - (Nk*4) ] ^ temp[ctr3] );
                        i++;
                    }
                    i-=8;
            }
    }

    public  void chiffre (byte[] state)
    {
           AddRoundKey(state, (byte)0);
            for(byte rnd=1; rnd<Nr; rnd++)
            {
                    ByteSub(state);
                    ShiftRow(state);
                    MixColumn(state);
                    AddRoundKey(state, rnd);
            }
            ByteSub(state);
            ShiftRow(state);
            AddRoundKey(state,Nr);
    }

    public void dechiffre(byte[] state)
    {
            AddRoundKey(state,Nr);
            for(byte rnd=(byte)(Nr-1); rnd>0; rnd--)
            {
                    InvShiftRow(state);
                    InvByteSub(state);
                    AddRoundKey(state,rnd);
                    InvMixColumn(state);
            }
            InvShiftRow(state);
            InvByteSub(state);
            AddRoundKey(state, (byte)0);
    }
}