The cause of this is how the secret key is generated using SecureRandom. We currently set a seed, and while this worked with the sun.security.provider.Sun provider, it was just by chance. With that provider the key would be the same as long as the same seed was provided, but this is not guaranteed or something that should be counted on. We need to come up with a different solution that is also performant. I've got the following branch with a suggestion for an alternative solution.