You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 26 Next »

Motivation

Cache encryption key rotation required in case of it compromising or at the end of crypto period (key validity period). in addition, such feature is required to provide support for encrypt and descrypt existing caches in the future.

Security requirement

Payment card industry data security standard (PCI DSS) requires that key-management procedures include a defined cryptoperiod for each key type in use and define a process for key changes at the end of the defined cryptoperiod(s). An expired key should not be used to encrypt new data, but it can be used for archived data, such keys should be strongly protected (section 3.5 - 3.6) [1].
The maximum recommended key lifetime is 2 years [2], and on average it is supposed to be changed every few months [3].

Key rotation in other systems

MS SQL Server provide rotation of database encryption key with background re-encryption of existing data [4]. Oracle and MySQL, out of the box, do not provide an automatic procedure for rotating tablespace keys, master key rotation is supported [5][6], Currently, TDE is being developed for PostgreSQL, but support for tablespace key rotation is not planned [7].

Overview

Local partition re-encryption strategy is similar to partition snapshotting - create partition snapshot encrypted with the new key and then replace the original partition file with the new one.

Cluster-wide process consists of the following steps:

  • Prepare changing the encryption key - send new key and start re-encryption task on each affinity node.
  • Finish changing the encryption key - swap partitions and replace cache encryption key in the metastore.

Prepare changing the encryption key

  1. The node initiator generates new encryption key(s) for cache group(s) and begins new distributed process to start a new cache encryption key change operation by sending an initial discovery message with the list of re-encrypted cache groups and encrypted keys.
  2. The distributed process configured action initiates a new local re-encryption task on each node.

Local re-encryption task

  1. Start copying of each partition file (including index) to the target directory with the re-encryption. These files will have dirty data due to concurrent checkpoint thread writes.
  2. Collect all dirty pages related to ongoing checkpoint process and corresponding partition files and apply them (with re-encryption) to the copied file right after the copy process ends.
  3. When local re-encryption of all required cache groups completes - send message that this phase is finished on this node (in other words, distributed process "prepare" is finished on local node).
  4. Continue to collect and apply dirty pages encrypted with the new key to copied partition until "finish" phase is started.

Finish changing the encryption key

After completion of the key change preparation process, a new distributed process is initiated to complete the key change.

The discovery event from the distributed process pushes a new exchange task to the exchange worker to start PME free switch (it is required to prevent reordering of WAL records when key will be changed and to simplify initial design, this could be changed in the future)

While updates are blocked each node:

  1. Forces the checkpoint (required for WAL consistency?)
  2. Swap all partition files:
    1. Backup original file.
    2. Move re-encrypted file to the place of the original one.
  3. Change encryption key(s) in metastore (update encryption keys history - add new key and set current WAL pointer to previous key).
  4. Remove partition backups (2a).

WAL

After changing the encryption key, new WAL records will be encrypted with the new key. However, it must be possible to read older WAL records (at least to support historical rebalance).

reference documentsFor each cache, instead of a key, it is necessary to keep a history of keys in the form WALPointer -> key
(stored the maximum pointer for which the associated key is applicable).

When removing a WAL segment to which WALPointer(s) refers - key(s) should be also removed.
When the WAL is cleared, respectively, the key history must also be cleared (except the last one).

Recovery

The re-encryption procedure does not start if there are LOST partitions in the cache group or any baseline node is missing (this is a limitation of the initial design and should be improved in the future).
The cache stop operation is rejected, for cache groups in which re-encryption is performed.

By canceling the re-encryption procedure is meant clearing all temporary data.

If a node crashes during the replacement of the partitions, the original backup copies of the partitions are restored when the node starts.
If major topology changes during key rotation - cancelling whole procedure.
Minor topology changes should not affect re-encryption procedure.
If the partition is scheduled for eviction during re-encryption, cancel the re-encryption of this partition.

Process management

TBD

Public API changes

TBD

Monitoring

Re-encryption process state. 

  • Input: cache id. 
  • Output: 
    • List of Tuples6 
      • Node ID 
      • Reencryption process state. 
      • Count of partition to process. 
      • Current partition index. 
      • Current partition id. 
      • Count of processed page in current partition. 

Reference Links

  1. PCI DSS Requirements and Security Assessment Procedures
    https://www.pcisecuritystandards.org/documents/PCI_DSS_v3-2-1.pdf
  2. How Often Do I Need to Rotate Encryption Keys on My SQL Server?
    https://info.townsendsecurity.com/bid/49019/How-Often-Do-I-Need-to-Rotate-Encryption-Keys-on-My-SQL-Server
  3. PCI DSS and key rotations simplified
    https://www.crypteron.com/blog/pci-dss-key-rotations-simplified/
  4. Transparent Data Encryption in MS SQL Server
    https://docs.microsoft.com/en-us/sql/relational-databases/security/encryption/transparent-data-encryption?view=sql-server-ver15
  5. Oracle Transparent Data Encryption FAQ
    https://www.oracle.com/database/technologies/faq-tde.html
  6. InnoDB Data-at-Rest Encryption
    https://dev.mysql.com/doc/refman/8.0/en/innodb-data-encryption.html
  7. Transparent data encryption feature proposed in pgsql-hackers.
    https://wiki.postgresql.org/wiki/Transparent_Data_Encryption#Key_Rotation

Tickets

Unable to render Jira issues macro, execution error.

  • No labels

Apache Ignite