BLTI-195 Add the unit tests of the encryption.


git-svn-id: https://source.sakaiproject.org/svn/basiclti/branches/BLTI-195@120395 66ffb92e-73f9-0310-93c1-f5514f145a0a
BLTI-195 Reduce key size to 128 bits as otherwise users have to install JCE policy.

128 is the maximum that can be used as AES key size without an unlimited strength policy file. To make installation easy dropping down to 128 bits is the simple solution.

git-svn-id: https://source.sakaiproject.org/svn/basiclti/branches/BLTI-195@120398 66ffb92e-73f9-0310-93c1-f5514f145a0a