keystore: Add flag for blobs to be unencrypted

In order to let apps use keystore more productively, make the blob
encryption optional. As more hardware-assisted keystores (i.e., hardware
that has a Keymaster HAL) come around, encrypting blobs start to make
less sense since the thing it's encrypting is usually a token and not
any raw key material.

(cherry picked from commit 0c540aad5915e6aa34345049be96f28b64d0e84c)

Bug: 8122243
Change-Id: Ie97f6df1ba141b1ed8007413ec1a834b0486cc2a
5 files changed
tree: 238553fe6db81c5aaabd11f05e9a999cf3db03dc
  1. keystore/
  2. keystore-engine/
  3. softkeymaster/