SOLR-16613: CryptoKeys should handle RSA padding for OpenJ9

[risdenk]

https://issues.apache.org/jira/browse/SOLR-16613

Tested with:

# With Temurin 17
./gradlew test --tests TestRSAKeyPair
./gradlew test --tests TestPKIAuthenticationPlugin

# With OpenJ9 17
RUNTIME_JAVA_HOME=/Library/Java/JavaVirtualMachines/ibm-semeru-open-17.jdk/Contents/Home ./gradlew test --tests TestRSAKeyPair
RUNTIME_JAVA_HOME=/Library/Java/JavaVirtualMachines/ibm-semeru-open-17.jdk/Contents/Home ./gradlew test --tests TestPKIAuthenticationPlugin

[risdenk]

random().nextBytes() would end up with null bytes and that would cause issues. I switched this to generate a regular string with no null bytes.

[uschindler]

Thanks for inviting me to review, but this is far away from my knowledge. I try to avoid crypto apis in Java.

[madrob]

Should we switch the algorithm from no padding to something with padding?

[risdenk]

Should we switch the algorithm from no padding to something with padding?

probably at some point. I don't really want to tackle that with this. This at least cleans up the build failures.

Let me add one more thing related to this - as far as I can tell the whole "RSA Encryption" stuff in question here - is really just a signature and shouldn't be done this way. This is encrypting with private key and verifying with public key. There are signatures for that instead. Not sure why its done this way, but it MIGHT be that the whole NoPadding stuff is really just working around using the right cryptography approach of a signature.