...

Motivation

Master keyrotation required in case of it compromising  is required if it has beencompromisedor at the end of  the crypto period (key validity period). 

Design assumes that , an administrator will provide an ability to get a new master key by EncryptionSPI from underlying storage.

...

• MK – MasterKey. Encrypts group keys. Master key is stored in some key storage. Master keys are identified by name.

Prerequisites

New master key should must be available to EncryptionSPI for each server node. The cluster should must be active.

Process management

Users can control the master key rotation process key via  some kind of user interface(CLI, JMX, Java API). 

...

1. Prepare master key change.
2. Perform master key change.

Each phase is a distributed process.

Prepare master key change

The goal is to verify that all server nodes have the same master key. A The server node starts begins prepare phase with the MasterKeyChangeRequest that contains:

...

Each server node executes the following actions:

1. It obtains Obtains a digest of a new master key. If the digest is unavailable then , the process completes with the an error.

2. Compares it with the one in messagethe request.
3. If it differs then the process completes with an error checking the consistency of the master key digest consistency check error.
4. Store Stores locally master key name and digest.

The coordinator starts the perform phase when the prepare phase is completed without errors.

...

The coordinator node starts the prepare phase with the MasterKeyChangeRequest that contains:

...

Each server node executes the following actions:

1. It checks that the cluster is active (WAL should be available for a write must be writable to correctly log changes and survive cluster restarts). Otherwise, the process completes with the error.
2. Checks that master key name and digest is the same as it was taken from the prepare phase. Otherwice, log it and cancel the process.
3. Blocks creation of encrypted cache keygroupkeys.
4. Reencrypt Re-encrypts all cache group keys with new master key in a temporary datastructure. No changes in MetaStore.
5. Create Creates WAL logical record (ChangeMasterKeyRecord ) that consist of:
   1. New master key name.
      
   2. Reenctyped cache group keys.
6. Write Writes cache group keys to MetaStore .
7. Unblock Unblockscreation of encrypted cache keygroupkeys.

Distributed process

Distributed process is a cluster-wide process that accumulates single nodes results to finish itself.

...

1. The initial request starts the process. The InitMessage sent via discovery.
2. Each server node processes an the initial request and sends the single node result to the coordinator. The SingleNodeMessage sent via communication.
3. The coordinator accumulate all single nodes results and finish completes process. The FullMessage sent via discovery.

Several processes of one the same type can be started at the same time.

Guarantees:

• Survives on topology and coordinator change (the SingleNodeMessage with a result will be redirected to the new one).
• The exec and the finish actions will be called only ones.

Process completion

The process completes when the perform phase completed (all nodes was have been re-encrypts encrypted their keys).

Corner cases

Node was down during key rotation. MasterKeyChangeRecord

...

not found.

If some node was unavailable during master key rotation process it will unable to join to the cluster because it has old master key.

To update this node user should run ignite Ignite with system property (IGNITE_MASTER_KEY_NAME_TO_CHANGE_BEFORE_STARTUP=newMasterKeyName)

The node will re-encrypt cache keys with new MK and try to join to the cluster.

Node was down during key rotation. MasterKeyChangeRecord found.

A node should not try to join to the cluster before the process of ChangeMasterKeyRecord. Regardless of whether the key rotation was finished successfully or not, the recovery will will  be from the record.

1. If during node recovery with logical records we found ChangeMasterKeyRecord  in the process node recovery it was passed to EncryptionManager .
2. When MetaStore becomes available for writewritable, EncryptionManager  writes new cache group keys to it.

...

Reject node join. It may lead to inconsistent master keys in cluster.

...

Starting cache during key rotation process

Cache keys must not be created during the master key rotation process. So, a node will throw an exception if a user users will start cache during the key rotation process. Moreover, if group keys were generated before the master key was change, starting the cache start will be rejected (case of client node starts the cache).

...

Node couldn’t complete the perform phase

...

The node Node will process the critical failure error failure. Failure handler must stop the node to prevent inconsistent keys in the cluster.

...

• setMasterKeyName(String masterKeyName)  // Sets "current" master key name
• String getMasterKeyName()  // Gets "current" master key name

Follow The following methods will work with master key that setted was set by previous method:

• byte[] masterKeyDigest() 
• byte[] encryptKey(Serializable key) 
• Serializable decryptKey(byte[] key) 

This is necessary so that ignite Ignite can decrypt cache keys with the old master key and encrypt with the new one.

...

Meta Storage

Meta storage will store name of master key name. Key name from meta storage has a higher priority to key name from EncryptionSpi .

Node attribute

Currently, the joining node send sends hash MK for validation in attributes. Attributes can't be modified at runtime. So the joining node will send hash MK in JoiningNodeDiscoveryData .

...