Data at Rest Encryption¶

Prerequisites¶

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

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.

Checking¶

If there is a general tablespace which doesn’t include tables yet, sometimes user needs to find out whether it is encrypted or not (this task is easier for single tablespaces since you can check table info).

A flag field in the INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES has bit number 13 set if tablespace is encrypted. This bit can be ckecked with flag & 8192 expression in the following way:

>SELECT space, name, flag, (flag & 8192) != 0 AS encrypted FROM INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES WHERE name in ('foo', 'test/t2', 'bar', 'noencrypt');
+-------+-----------+-------+-----------+
| space | name      | flag  | encrypted |
+-------+-----------+-------+-----------+
|    29 | foo       | 10240 |      8192 |
|    30 | test/t2   |  8225 |      8192 |
|    31 | bar       | 10240 |      8192 |
|    32 | noencrypt |  2048 |         0 |
+-------+-----------+-------+-----------+
4 rows in set (0.01 sec)

System Variables¶

variable innodb_temp_tablespace_encrypt¶

Version Info:	5.7.21-21 – Implemented
Command Line:	--innodb-temp-tablespace-encrypt
Dynamic:	Yes
Scope:	Global
Variable Type:	Boolean
Default Value:	Off

When this option is turned on, server starts to encrypt temporary tablespace and temporary InnoDB file-per-table tablespaces. The option does not force encryption of temporary tables which are currently opened, and it doesn’t rebuild system temporary tablespace to encrypt data which are already written.

Since temporary tablespace is created fresh at each server startup, it will not contain unencrypted data if this option specified as server argument.

Turning this option off at runtime makes server to create all subsequent temporary file-per-table tablespaces unencrypted, but does not turn off encryption of system temporary tablespace.

variable innodb_encrypt_tables¶

Version Info:	5.7.21-21 – Implemented
Command Line:	--innodb-encrypt-tables
Dynamic:	Yes
Scope:	Global
Variable Type:	Text
Default Value:	OFF

This variable has 3 possible values. ON makes InnoDB tables encrypted by default. FORCE disables creation of unencrypted tables. OFF restores the like-before behavior.

System Variables¶

variable encrypt_binlog¶

Version Info:	5.7.20-19 – Implemented
Command Line:	--encrypt-binlog
Dynamic:	No
Scope:	Global
Variable Type:	Boolean
Default Value:	OFF

The variable turns on binary and relay logs encryption.

System Variables¶

variable encrypt-tmp-files¶

Version Info:	5.7.22-22 – Implemented
Command Line:	--encrypt-tmp-files
Dynamic:	No
Scope:	Global
Variable Type:	Boolean
Default Value:	OFF

The option turns on encryption of temporary files created by Percona 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.

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.

System Variables¶

variable keyring_vault_config¶

Version Info:	5.7.20-18 – Implemented
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:	5.7.21-20 – Implemented
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 to wait infinite amount of time by setting this variable to 0.

Other reading¶

• Vault Documentation
• General-Purpose Keyring Key-Management Functions