Alex Klyubin 4ab8ea4498 Add HmacSHA256 backed by AndroidKeyStore.
This also adds the MAC length constraint on imported HMAC keys. HMAC
doesn't work without this constraint at the moment.

Bug: 18088752
Change-Id: I8613f58f5d2a84df00bcf6179d13e30619440330
2015-03-30 12:53:23 -07:00
..