Add more comment on why `KeyUtil::getKeySize` could return -1. Add a new method `getNistCategory` to get the NIST security category.
------------- Commit messages: - the fix Changes: https://git.openjdk.org/jdk/pull/25642/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25642&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8358594 Stats: 112 lines in 2 files changed: 110 ins; 0 del; 2 mod Patch: https://git.openjdk.org/jdk/pull/25642.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/25642/head:pull/25642 PR: https://git.openjdk.org/jdk/pull/25642
