Hi @rnapier. Sorry for being AWOL. I wasn't receiving any emails about RNCryptor so it was out of sight out of mind.
I have migrated the project to use hash_equals() along with the polyfill library. I also took the opportunity to fix up our TravisCI configs. Since PHP 5.4 is at EOL, I have moved the minimum supported PHP version to 5.5. I also added support for testing in PHP7.