size = ( size % 2 == 0 ) ? size / 2 : size / 2 + 1;
        for( int i = 0, j = 0; i < size; i++ ) {
            c[j++] = HEX_DIGITS[(src[i] >> 4 ) & 0x0F];
            if( j == c.length ) {
                break;
            }
            c[j++] = HEX_DIGITS[src[i] & 0x0F];
        }
        return new String( c );
    }

/** 

     * @param src
     * @param srcIndex
     * @param size
     * @return hex string
     */
    public static String toHexString ( byte[] src, int srcIndex, int size ) {
        char[] c = new char[2 * size];
        for ( int i = 0, j = 0; i < size; i++ ) {
            c[ j++ ] = HEX_DIGITS[ ( src[ srcIndex + i ] >> 4 ) & 0x0F ];
            c[ j++ ] = HEX_DIGITS[ src[ srcIndex + i ] & 0x0F ];
        }
        return new String(c);