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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].
At the moment, encryption occurs at the pagememory level, when a page is written to the pagestore or WAL.
This strategy is similar to partition partition snapshotting - create partition snapshot encrypted with the new key and then replace the original partition file with the new one.
Sequentially read all the pages from the datastore and mark as dirty, log them into WAL. Checkpointer writes the pages encrypted with the new key.
This strategy requires changing the format of the encryption page to store the identifier (number) of the encryption key (for recovery). Each encrypted page has a space reserved for a page crc (4 bytes) that has an encryption block size (minimum 8 bytes).
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Performance(rough estimate)
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Implementation complexity (rough estimate)
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The
The overall process consists of the following steps
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To support multiple keys for reading encrypted data it is required to store a key identifier on each encrypted page and on each encrypted WAL record (see more details). The key identifier is a sequential counter , and should be the same on all nodes.
After the FINISH phase is complete, a new encryption key for writing is set on all nodes, i.e. the key change process is formally completed.
Background re-encryption of existing data will be completed sometime in the future, the new "reencryptionFinished" cache group metric can be used to track re-encryption progress.
Process The process applies only for OWNING/MOVING partitions that are not currently clearedall existing partitions including index.
Every time the cache group key changes, we store the current page count of the partition in the meta page (this value is used as the total page count to re-encrypt).
Scan all pages from specified range (metapageid metaPageId + [offset -> total])
Re-encryption progress is stored into metapage (int offset, int total), it updates during the checkpoint.
The process aborts for partition that only when a partition is destroyed.
At node startup, during partition initialization, if the total number of pages for re-encryption is greater than zero - this cache group is scheduled for evicting/clearing during re-encryption.
Old cache group encryption key will be removed when
If GROUP_KEY_CHANGE_PREPARE has not been successfully completed on all nodes, the process is interrupted and must be restarted.
When the process restarts, a new key identifier is generated (an unused key will be removed on finish-phase, when we set the new key for writing).
It is possible that the node will fail after adding a new key, but before setting it for writing (as an *active* key).
This node doesn't know whether the PREPARE phase was successful or not, therefore, it does not know which key is currently being used for writing.
By default, it will try to rejoin with the old key, if the join is rejected, then it should be possible to manually set the correct key identifier using the system property or command line tools.
// TBD
// TBD
Cluster-wide process consists of the following steps:
After completion of the key change preparation process, a new distributed process is initiated to complete the key change.
The distributed process configured action initiates partition swapping on each node (this action may require suspension of local or global operations if WAL records can be reordered during key change).
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).
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.
TBD
TBD
Re-encryption process state.
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Reencryption status requires an additional 8 bytes on the meta page of each partition.
Index partition uses PageMetaIO to read/write meta information (page type T_META).
Each other partition uses PagePartitionMetaIO to read/write meta information (page type T_PART_META).
Partition meta starts just after the end of the page meta.
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To support binary compatibility and keep code clean we creating a new successor of PageMetaIO - PageMetaIOV2 with the same type T_META.
We converting all existing T_META pages into a new version.
We storing additional 8 bytes at the end of each T_META and T_PART_META memory pages.
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WAL delta records have also been modified to store re-encryption status.
Each encrypted page has reserved free space to store CRC of encrypted data.
The size of this free space depends on the size of the encryption block, but cannot be less than 8 bytes (Ignite default encryption implementation (KeystoreEncryptionSpi) uses AES with 16 bytes block size).
Added 1 byte for encryption key ID on each encrypted page (after CRC).
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Node join is rejected during the key rotation, but this limitation may be revised in the future.
When a node joins the cluster (before/after key rotation), it receives the current encryption keys for the cache groups used for writing. If the encryption key is a new key, then the node sets it for writing and starts the background re-encryption process (in other words, the node automatically "rotates" the encryption key. when joining a cluster, if necessary).
Therefore, a node may leave the cluster during a key change, or a node may be absent and rejoin later (it does not matter if the baseline changes or not), it will receive a new key and schedule re-encryption, if necessary.
If the node stops/fails during re-encryption, after restarting it continue re-encryption from the stored offset:
New method will be introduced
public IgniteFuture<Void> changeCacheGroupKey(Collection<String> cacheOrGroupNames)
Re-encryption process state in CacheGroupMetrics
The following commands should be added to the control.sh utility:
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control.(sh|bat) --encryption change_cache_key cacheGroupName --yes |
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The encryption key has been changed for cache group "default". |
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control.(sh|bat) --encryption cache_key_ids cacheGroupName |
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Encryption key identifiers for cache: default
Node 6085d500-2736-4c1f-b47c-444cf0a00000:
1 (active)
0
Node d98654c0-6dfb-4996-993e-387156300001:
1 (active)
0 |
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control.(sh|bat) --encryption reencryption_status cacheGroupName |
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Node 4ed26231-f92d-4b1c-86ba-7a117c200001:
1552 KB of data left for re-encryption
Node 89a456e5-59c5-4f13-a75b-39ab25000000:
1552 KB of data left for re-encryption |
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control.(sh|bat) --encryption suspend_reencryption cacheGroupName |
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Node ad1328e7-11e0-4ecb-8ef2-066519e00001:
re-encryption of the cache group "default" has been suspended.
Node 2a9e291f-e2d1-46e3-9954-18deb0e00000:
re-encryption of the cache group "default" has been suspended. |
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control.(sh|bat) --encryption resume_reencryption cacheGroupName |
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Node 2ed43509-caab-48dc-a27d-3be65d800000:
re-encryption of the cache group "default" has been resumed.
Node b52d6451-a948-48d5-b79a-411956700001:
re-encryption of the cache group "default" has been resumed. |
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control.(sh|bat) --encryption reencryption_rate [limit]
Parameters:
limit - decimal value to change rate limit (MB/s) |
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Node 15cb8485-0c09-4361-b267-107d38400000:
re-encryption rate has been limited to 0.01 MB/s.
Node 909ed414-22e6-477b-b2ca-d1934cd00001:
re-encryption rate has been limited to 0.01 MB/s. |
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Jira server ASF JIRA columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution maximumIssues 20 jqlQuery project = Ignite AND labels in (tde-phase-3) ORDER BY status serverId 5aa69414-a9e9-3523-82ec-879b028fb15b key IGNITE-12843