[SHIRO-736] default to PaddingScheme.NONE when using GCM

[bmarwell]

Issue: https://issues.apache.org/jira/browse/SHIRO-736

AES/GCM/PKCS5Padding is an alias for AES/GCM/NoPadding on most JVMs. Some JVMs do not have this alias defined, which results in an Exception with the default configuration.

org.apache.shiro.crypto.CryptoException: Unable to acquire a Java JCA Cipher instance using javax.crypto.Cipher.getInstance( "AES/GCM/PKCS5Padding" ). AES under this configuration is required for the org.apache.shiro.crypto.AesCipherService instance to function.
Caused by: java.security.NoSuchAlgorithmException: Cannot find any provider supporting AES/GCM/PKCS5Padding
  at javax.crypto.Cipher.getInstance(Unknown Source)
  at org.apache.shiro.crypto.JcaCipherService.newCipherInstance(JcaCipherService.java:408)

[bmarwell]

Before merging, maybe get approval of the apache sercurity team?

[bdemers]

@bmhm which JVM are you using?
NM, I found your answer on the dev list:

older (Adopt Open / IBM) J9 JVMs

[bmarwell]

You can download it from wadev central along with liberty profile.

The open source variant is eclipse openj9, which you can get from adoptopenjdk.net.