I have used Cisco's Software Advisor to look for differences in the crypto and non-crypto images. For several releases the Advisor does not list any differences. I did find a release 12.1EA1 where it did list differences. As far as authentication services there were no differences listed. It did list support for SSH in the crypto image which is not in the non-crypto image. So depending on how broad your definition of services is there may be a difference that you might care about.
HTH
Rick
HTH
Rick