* Introduce BlobCipher interface and cipher caching interface
diff-3: Update the code to avoid deriving encryption key periodically.
Implement EncyrptBuf interface to limit memcpys.
Improve both unit test and simulation to better code coverage.
diff-2: Add specific error code for OpenSSL AES call failures
diff-1: Update encryption scheme to AES-256-CTR. Minor
updates to Header to capture more information.
Major changes proposed are:
1. Introduce encyrption header format.
2. Introduce a BlobCipher cipher key representation encoding
following information: baseCipher details, derived encryption cipher
details, creationTime and random salt.
3. Introduce interface to support block cipher encrytion and decrytion
operations. Encyrption populates encryption header allowing client to
persist them on-disk, this header is then read allowing decryption
on reads.
4. Introduce interface to allow in-memory caching of cipher keys. The
cache allowing mapping of "encryption domain" -> "base cipher id" ->
"derived cipher keys" (3D hash map). This cache interface will be used
by FDB processes participating in encryption to cache recently used
ciphers (performance optimization).
Testing:
1. Unit test to validate caching interface.
2. Update EncryptionOps simulation test to validate block cipher
operations.
Description
Major changes proposed are:
1. Rename ServerKnob->ENABLE_ENCRYPT_KEY_PROXY to
ServerKnob->ENABLE_ENCRYPTION. Approach simplifies enabling
controlling encyrption code change using a single knob (desirable)
2. Implement EncyrptKeyVaultProxy simulated interface to assist
validating encyrption workflows in simulation runs. The interface
is leveraged to satisfy "encryption keys" lookup which otherwise
gets satisfied by integrating organization preferred Encryption
Key Management solution.
Testing
Unit test to validate the newly added code
Major changes includes:
1. Add a new FDB role responsible- EncyrptKeyProxy. The role is
responsible to expose APIs to fetch encyrption keys interacting
with external Encryption KeyManager interface.
2. The process is a FDB singleton process following similar recruitment
rules as other singleton processes in the system.
3. Code to recruit the worker process; given the encryption keys are
needed during recovery (decode TLog records), for now the process
is co-located in same datacenter as ClusterController.
4. Skeleton process actor code; more functionality will be added in
subsequent PRs.
NOTE: The code is protected under a SERVER_KNOB with the default
value as 'false' for now.
In this PR, the blob manager now recruits blob workers
(via communication with the cluster controller). Blob workers
are onboarded as blob worker processes enter the cluster.