密码块链接/密文窃取java

Question

为了更好地理解CBC和CTS，我试图改造我自己的类，它可以加密和解密而不使用java的内置CTS模式。我使用AES包装类作为底层算法，但使用CTS作为操作模式。到目前为止，我一直在研究加密方法，但不知道从那里去哪里。我不确定如何在CTS模式结束时实现块的交换。

以下是我目前为我的加密方法编写的代码（并且不用担心它可以100％运行的AES类）：

    static byte[] encrypt(byte[] ptBytes, javax.crypto.SecretKey key, byte[] IV){

    byte [] ct; 
    byte [] pt;
    byte [] ptBlock, ctBlock;

    //pad the array to proper length
    pt = Arrays.copyOf(ptBytes, (int) (Math.ceil( ( ptBytes.length )/16)*16) );

    //ctBlock = one block of cipher text
    ctBlock = new byte [16];

    //make ct the length of the padded pt 
    ct = new byte [pt.length];

    //do the encryption
    //i is for the current block of plain / cipher text we are on
    for( int i = 1; i < (int) ((Math.ceil( ( ptBytes.length )/16)+1)); i++){
        if( i == 1 ){

            //make ptBlock the first block of the entire plain text
            ptBlock = Arrays.copyOfRange(pt, 0, (i*16)-1);

            //since i = 1 do the XOR to get new plain text with IV
            for (int j = 0; j < ptBlock.length - 1; j++){
                ptBlock[j] = (byte)(ptBlock[j] ^ IV[j]);
            }

            //now time to do the encryption between the current block of plain text and the key
            try {
                ctBlock = AES.encrypt(ptBlock, key);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            //now put the cipher text block we just got into the final cipher text array
            for( int k = 0; k < ctBlock.length; k++){
                ct[k] = ctBlock[k];
            }

        }
        else{
            //make ptBlock the current number block of entire plain text
            ptBlock = Arrays.copyOfRange(pt, (i-1)*16, (i*16)-1);

            //now XOR the plain text block with the prior cipher text block
            for(int j = 0; j < ptBlock.length - 1; j++){
                ptBlock[i] = (byte) (ptBlock[j] ^ ctBlock[j]);
            }

            //now time to do the encryption between the current block of plain text and the key
            try {
                ctBlock = AES.encrypt(ptBlock, key);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            //now put the cipher text block we just got into the final cipher text array
            for( int k = (i-1)*16; k < (i*16)-1; k++){
                ct[k] = ctBlock[k-16];
            }
        }
    }






    return ct;
}

如果有人能够对如何完成这种方法有所了解，那将是很好的，因为我仍在学习CBC / CTS的来龙去脉

谢谢！