RFR: 8299817: [s390] AES-CTR mode intrinsic fails with multiple short update() calls

[Lutz Schmidt]

On Thu, 12 Jan 2023 14:29:34 GMT, Lutz Schmidt <lucy at openjdk.org> wrote:

> This PR addresses an issue in the AES-CTR mode intrinsic on s390. When a message is ciphered in multiple, small (< 16 bytes) segments, the result is incorrect.
> 
> This is not just a band-aid fix. The issue was taken as a chance to restructure the code. though still complicated, It is now easier to read and (hopefully) understand.
> 
> Except for the new jetreg test, the changes are purely s390. There are no side effects on other platforms. Issue-specific tests pass. Other tests are in progress. I will update this PR once they are complete. 
> 
> **Reviews and comments are very much appreciated.**
> 
> @backwaterred could you please run some "official" s390 tests? Thanks.

Thank you for testing, Amit. 
In addition to that, an identical version of the code runs in our internal tests for our commercial product. Everything is fine there as well.

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PR: https://git.openjdk.org/jdk/pull/11967