Re: Simple encryption/decryption

Seems to work:

package fubar;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class Encryption {

     Cipher rc4;
     SecretKey rc4Key;

     public Encryption( String password )
             throws NoSuchAlgorithmException,
             NoSuchPaddingException,
             InvalidKeySpecException,
             InvalidKeyException
     {
         rc4 = Cipher.getInstance( "RC4" );
         rc4Key = new SecretKeySpec( password.getBytes(), "RC4" );
         rc4.init( Cipher.ENCRYPT_MODE, rc4Key );
     }

     public byte[] crypt( byte[] input )
             throws IllegalBlockSizeException,
             BadPaddingException
     {
         return rc4.doFinal( input );
     }

     public static void main ( String... args )
             throws Exception
     {
         // RC4 test vectors from Wikipedia
         // Only "Secret" is long enough to supply the required
         // 40 bits.

         String [][] testVectors = { { "Secret", "Attack at dawn"} };

         for( String[] s : testVectors ) {
             Encryption encryption = new Encryption( s[0] );
             System.out.println( hexBytes( encryption.crypt(
                     s[1].getBytes() ) ) );
         }
     }

     private static String hexBytes( byte[] bytes ) {
         StringBuilder sb = new StringBuilder( bytes.length *2 );
         for( int i = 0; i < bytes.length; i++ ) {
             sb.append( String.format( "%02X", bytes[i] ) );
         }
         return sb.toString();
     }

}