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Data at Rest Encryption

This feature is considered BETA quality.

InnoDB general tablespace encryption

In Percona Server 5.7.20-18 existing tablespace encryption support has been extended to handle general tablespaces. A general tablespace is either fully encrypted, covering all the tables inside, either not encrypted at all. It is not possible to have only some of the tables in the general tablespace encrypted.

This feature extends the CREATE TABLESPACE statement to accept the ENCRYPTION='Y/N' option.

Prerequisites

This feature requires a keyring plugin, for example keyring_file or Keyring Vault plugin to be loaded before it can be used.

Warning

Only one keyring plugin should be enabled at a time. Enabling multiple keyring plugins is unsupported and may result in data loss.

Usage

General tablespace encryption is enabled by the following syntax extension:

mysql> CREATE TABLESPACE tablespace_name ... ENCRYPTION='Y'

Attempts to create or to move tables, including partitioned ones, to a general tablespace with an incompatible encryption setting are diagnosed and aborted.

As you cannot move tables between encrypted and unencrypted tablespaces, you will need to create another table, add it to a specific tablespace and run INSERT INTO SELECT from the table you want to move from, and then you will get encrypted or decrypted table with your desired content.

Example

To create an encrypted tablespace run:

mysql> CREATE TABLESPACE foo ADD DATAFILE 'foo.ibd' ENCRYPTION='Y';

To add an encrypted table to that table space run:

mysql> CREATE TABLE t1 (a INT, b TEXT) TABLESPACE foo ENCRYPTION="Y";

Trying to add unencrypted table to this table space will result in an error:

mysql> CREATE TABLE t3 (a INT, b TEXT) TABLESPACE foo ENCRYPTION="N";
ERROR 1478 (HY000): InnoDB: Tablespace `foo` can contain only an ENCRYPTED tables.

Note

Percona XtraBackup currently doesn’t support backup of encrypted general tablespaces.

Binary log encryption

A new option, implemented since Percona Server 5.7.20-19, is encryption of binary and relay logs, triggered by the encrypt_binlog variable.

Besides turning encrypt_binlog ON, this feature requires both master_verify_checksum and binlog_checksum variables to be turned ON.

While replicating, master sends the stream of decrypted binary log events to a slave (SSL connections can be set up to encrypt them in transport). That said, masters and slaves use separate keyring storages and are free to use differing keyring plugins.

Dumping of encrypted binary logs involves decryption, and can be done using mysqlbinlog with --read-from-remote-server option.

Note

Taking into account that --read-from-remote-server option is only relevant to binary logs, encrypted relay logs can not be dumped/decrypted in this way.

System Variables

variable encrypt_binlog
Version Info:
Command Line:

--encrypt-binlog

Dynamic:

No

Scope:

Global

Variable Type:

Boolean

Default Value:

OFF

The variable turns on binary and relay logs encryption.

Keyring Vault plugin

In Percona Server 5.7.20-18 a keyring_vault plugin has been implemented that can be used to store the encryption keys inside the Hashicorp Vault server.

Installation

The safest way to load the plugin is to do it on the server startup by using –early-plugin-load variable option:

--early-plugin-load="keyring_vault=keyring_vault.so" \
--loose-keyring_vault_config="/home/mysql/keyring_vault.conf"

It should be loaded this way to be able to facilitate recovery for encrypted tables.

Warning

If server should be started with several plugins loaded early, --early-plugin-load should contain their list separated by semicolons. Also it’s a good practice to put this list in double quotes so that semicolons do not create problems when executed in a script.

Apart from installing plugin you also need to set the keyring_vault_config variable. This variable should point to the keyring_vault configuration file, whose contents are discussed below.

This plugin supports the SQL interface for keyring key management described in General-Purpose Keyring Key-Management Functions manual.

To enable the functions you’ll need to install the keyring_udf plugin:

mysql> INSTALL PLUGIN keyring_udf SONAME 'keyring_udf.so';

Usage

On plugin initialization keyring_vault connects to the Vault server using credentials stored in the credentials file. Location of this file is specified in by keyring_vault_config. On successful initialization it retrieves keys signatures and stores them inside an in-memory hash map.

Configuration file should contain the following information:

  • vault_url - the address of the server where Vault is running. It can be a named address, like one in the following example, or just an IP address. The important part is that it should begin with https://.
  • secret_mount_point - the name of the mount point where keyring_vault will store keys.
  • token - a token generated by the Vault server, which keyring_vault will further use when connecting to the Vault. At minimum, this token should be allowed to store new keys in a secret mount point (when keyring_vault is used only for transparent data encryption, and not for keyring_udf plugin). If keyring_udf plugin is combined with keyring_vault, this token should be also allowed to remove keys from the Vault (for the keyring_key_remove operation supported by the keyring_udf plugin).
  • vault_ca [optional] - this variable needs to be specified only when the Vault’s CA certificate is not trusted by the machine that is going to connect to the Vault server. In this case this variable should point to CA certificate that was used to sign Vault’s certificates.

An example of the configuration file looks like this:

vault_url = https://vault.public.com:8202
secret_mount_point = secret
token = 58a20c08-8001-fd5f-5192-7498a48eaf20
vault_ca = /data/keyring_vault_confs/vault_ca.crt

When a key is fetched from a keyring for the first time the keyring_vault communicates with the Vault server, and retrieves the key type and data. Next it queries the Vault server for the key type and data and caches it locally.

Key deletion will permanently delete key from the in-memory hash map and the Vault server.

Note

Percona XtraBackup currently doesn’t support backup of tables encrypted with Keyring Vault plugin.

System Variables

variable keyring_vault_config
Version Info:
Command Line:

--keyring-vault-config

Dynamic:

Yes

Scope:

Global

Variable Type:

Text

Default Value:

This variable is used to define the location of the Keyring Vault plugin configuration file.

variable keyring_vault_timeout
Version Info:
Command Line:

--keyring-vault-timeout

Dynamic:

Yes

Scope:

Global

Variable Type:

Numeric

Default Value:

15

This variable allows to set the duration in seconds for the Vault server connection timeout. Default value is 15. Allowed range is from 1 second to 86400 seconds (24 hours). The timeout can be also completely disabled by setting this variable to 0.

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