Encrypted Backups

Percona XtraBackup has implemented support for encrypted backups. This feature was introduced in Percona XtraBackup 2.1. It can be used to encrypt/decrypt local or streaming backup with xbstream option (streaming tar backups are not supported) in order to add another layer of protection to the backups. Encryption is done with the libgcrypt library.

Note

Encryption related options are currently ignored by innobackupex when specified in my.cnf.

Creating Encrypted Backups

To make an encrypted backup following options need to be specified (options --encrypt-key and --encrypt-key-file are mutually exclusive, i.e. just one of them needs to be provided):

  • --encryption=ALGORITHM - currently supported algorithms are: AES128, AES192 and AES256
  • --encrypt-key=ENCRYPTION_KEY - proper length encryption key to use. It is not recommended to use this option where there is uncontrolled access to the machine as the command line and thus the key can be viewed as part of the process info.
  • --encrypt-key-file=KEYFILE - the name of a file where the raw key of the appropriate length can be read from. The file must be a simple binary (or text) file that contains exactly the key to be used.

Both --encrypt-key option and --encrypt-key-file option can be used to specify the encryption key. Encryption key can be generated with command like:

$ openssl enc -aes-256-cbc -pass pass:Password -P -md sha1

Output of that command should look like this:

salt=9464A264486EEC69
key=DDD3A1B6BC90B9A9B631913CF30E0336A2571BA854E2D65CF92A6D0BDBCBB251
iv =A1EDC73815467C083B0869508406637E

In this case we can use iv value as key.

Using the --encrypt-key option

Example of the innobackupex command using the --encrypt-key should look like this

$ innobackupex --encrypt=AES256 --encrypt-key="A1EDC73815467C083B0869508406637E" /data/backups

Using the --encrypt-key-file option

Example of the innobackupex command using the --encrypt-key-file should look like this

$ innobackupex --encrypt=AES256 --encrypt-key-file=/data/backups/keyfile /data/backups

Note

Depending on the text editor used for making the KEYFILE, text file in some cases can contain the CRLF and this will cause the key size to grow and thus making it invalid. Suggested way to do this would be to create the file with: echo -n "A1EDC73815467C083B0869508406637E" > /data/backups/keyfile

Both of these examples will create a timestamped directory in /data/backups containing the encrypted backup.

Note

You can use the innobackupex --no-timestamp option to override this behavior and the backup will be created in the given directory.

Optimizing the encryption process

Two new options have been introduced with the encrypted backups that can be used to speed up the encryption process. These are --encrypt-threads and --encrypt-chunk-size. By using the --encrypt-threads option multiple threads can be specified to be used for encryption in parallel. Option --encrypt-chunk-size can be used to specify the size (in bytes) of the working encryption buffer for each encryption thread (default is 64K).

Decrypting Encrypted Backups

Backups can be decrypted with The xbcrypt binary. Following one-liner can be used to encrypt the whole folder:

$ for i in `find . -iname "*\.xbcrypt"`; do xbcrypt -d --encrypt-key-file=/root/secret_key --encrypt-algo=AES256 < $i > $(dirname $i)/$(basename $i .xbcrypt) && rm $i; done

In Percona XtraBackup 2.1.4 new innobackupex --decrypt option has been implemented that can be used to decrypt the backups:

$ innobackupex --decrypt=AES256 --encrypt-key="A1EDC73815467C083B0869508406637E" /data/backups/2013-08-01_08-31-35/

Use of the innobackupex --decrypt will remove the original encrypted files and leave the results in the same location.

Note

innobackupex --parallel can be used with innobackupex --decrypt option to decrypt multiple files simultaneously.

When the files have been decrypted backup can be prepared.

Preparing Encrypted Backups

After the backups have been decrypted, they can be prepared the same way as the standard full backups with the --apply-logs option:

$ innobackupex --apply-log /data/backups/2013-08-01_08-31-35/

Restoring Encrypted Backups

innobackupex has a --copy-back option, which performs the restoration of a backup to the server’s datadir

$ innobackupex --copy-back /path/to/BACKUP-DIR

It will copy all the data-related files back to the server’s datadir, determined by the server’s my.cnf configuration file. You should check the last line of the output for a success message:

innobackupex: Finished copying back files.
130801 11:08:13  innobackupex: completed OK!
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