OAISIM Security Algorithms v0.1

Dependencies:
- nettle >= 2.5
- openssl >= 1.0.1

Compilation:

When compiling oaisim, add SECU=1 to enable security features. The makefile will
check for required dependencies and disable this feature if not all dependencies
are met.

OSA is based on 3GPP TS 33.401.
Note that only EEA2 and EIA2 algorithms are supported, SNOW-3G is not implemented.

Currently the kenb used to derive kRRCint, kRRCenc and kUPenc is composed of the
UE_id. In the future this parameter can be either obtained by deriving KASME received
from core epc (in the S1AP initial context setup request)
or configurable via command line or XML file.
