On Wed, 5 Jun 2024 12:54:45 GMT, Francisco Ferrari Bihurriet
<fferr...@openjdk.org> wrote:
>> I have no personal preference, but would suggest that if we change it to cut
>> the pad, we keep the decryption case aligned.
>
> What I like about this suggestion is that it allows unifying the repeated
> logic: the two blocks inside `if (encrypt)` and the corresponding `else`
> would become almost identical, allowing an additional abstraction. How about
> the following?
>
>
> private void convertCTSVariant(ByteBuffer ciphertextBuf,
> byte[] ciphertextArr, int end) {
> // [...]
> // [...] omitted code
> // [...]
> if (ciphertextBuf != null) {
> pad = pad == 0 ? blockSize : pad;
> if (encrypt) {
> // .... pp[pp] ffff -> .... ffff pp[pp]
> swapLastTwoBlocks(ciphertextBuf, end, pad, blockSize);
> } else {
> // .... ffff pp[pp] -> .... pp[pp] ffff
> swapLastTwoBlocks(ciphertextBuf, end, blockSize, pad);
> }
> }
> }
>
> private static void swapLastTwoBlocks(ByteBuffer buffer, int end,
> int prevBlockLen, int lastBlockLen) {
> // .... prevBlock lastBlock -> .... lastBlock prevBlock
> int prevBlockStart = end - prevBlockLen - lastBlockLen;
> byte[] prevBlockBackup = new byte[prevBlockLen];
> buffer.get(prevBlockStart, prevBlockBackup);
> buffer.put(prevBlockStart, buffer, end - lastBlockLen, lastBlockLen);
> buffer.put(end - prevBlockLen, prevBlockBackup);
> }
Looks good to me.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/18898#discussion_r1627887918
