RFR: 8308118: Avoid multiarray allocations in AESCrypt.makeSessionKey [v2]

[Aleksey Shipilev]

On Tue, 16 May 2023 08:29:52 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> src/java.base/share/classes/com/sun/crypto/provider/AESCrypt.java line 1369:
>> 
>>> 1367:         int BC = 4;
>>> 1368:         int[][] Ke = new int[ROUNDS + 1][]; // encryption round keys
>>> 1369:         int[][] Kd = new int[ROUNDS + 1][]; // decryption round keys
>> 
>> This is more a question of curiosity and likely beyond the scope of this PR/bug ID -- would it be beneficial to refactor this to allocate and operate over just two arrays, one for Ke and one for Kd, effectively removing the need for allocation in `expandToSubKey` as well?
>> 
>> 
>> int[] Ke = new int[4 * (ROUNDS + 1)];
>> int[] Kd = new int[4 * (ROUNDS + 1)];
>
> True, let me try that!

New commit implements this, with even more performance benefits.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13996#discussion_r1194883146