SGSN: add preliminary support for GPRS encryption

It is already functional enough to allow testing with real
phones. However, note - there are several limitations in the current
implementation:

* only default value for IOV-UI is supported at the moment
* AUTN-based key material is not supported

Related: OS#1582
Change-Id: I8900b906693496e4e6b35be5a86937c58039ed9e
6 files changed
tree: 48b991298a745e79a59d04b7b1b522f91b885ced
  1. contrib/
  2. debian/
  3. openbsc/
  4. .gitignore
  5. .gitreview