As of MySQL 5.6.6, MySQL provides an authentication plugin that implements SHA-256 hashing for user account passwords.

The following table shows the plugin names on the server and client sides.

The server-side sha256_password plugin is built into the server, need not be loaded explicitly, and cannot be disabled by unloading it. Similarly, clients need not specify the location of the client-side plugin.

To set up an account that uses SHA-256 password hashing, use the following procedure.

Alternatively, start the server with the default authentication plugin set to sha256_password. For example, put these lines in the server option file:

[mysqld]
default-authentication-plugin=sha256_password

That causes the sha256_password plugin to be used by default for new accounts. As a result, it is possible to create the account and set its password without naming the plugin explicitly using this CREATE USER syntax:

CREATE USER 'sha256user'@'localhost' IDENTIFIED BY 'Sh@256Pa33';

In this case, the server assigns the sha256_password plugin to the account and encrypts the password using SHA-256.

Accounts in the mysql.user table that use SHA-256 passwords can be identified as rows with 'sha256_password' in the plugin column and a SHA-256 password hash in the authentication_string column.

Another consequence of using sha256_password as the default authentication plugin is that to create an account that uses a different plugin, you must specify that plugin using an IDENTIFIED WITH clause in the CREATE USER statement, then set old_passwords appropriately for the plugin before using SET PASSWORD to set the account password. For example, to use the mysql_native_password plugin, do this:

CREATE USER 'nativeuser'@'localhost' IDENTIFIED WITH mysql_native_password;
SET old_passwords = 0;
SET PASSWORD FOR 'nativeuser'@'localhost' = PASSWORD('N@tivePa33');

To set or change the password for any account that authenticates using the sha256_password plugin, be sure that the value of old_passwords is 2 before using SET PASSWORD. If old_passwords has a value other than 2, an error occurs for attempts to set the password:

mysql> SET old_passwords = 0;
mysql> SET PASSWORD FOR 'sha256user'@'localhost' = PASSWORD('NewSh@256Pa33');
ERROR 1827 (HY000): The password hash doesn't have the expected format.
Check if the correct password algorithm is being used with the
PASSWORD() function.

For more information about old_passwords and PASSWORD(), see Section 5.1.5, “Server System Variables”, and Section 12.13, “Encryption and Compression Functions”.

MySQL can be compiled using either OpenSSL or yaSSL (see Section 6.4.1, “OpenSSL Versus yaSSL”). The sha256_password plugin works with distributions compiled using either package, but if MySQL is compiled using OpenSSL, RSA encryption is available and sha256_password implements the following additional capabilities. (To enable these capabilities, you must also follow the RSA configuration procedure given later in this section.)

For clients that use the sha256_password plugin, passwords are never exposed as cleartext when connecting to the server. How password transmission occurs depends on whether an SSL connection is used and whether RSA encryption is available:

As mentioned previously, RSA password encryption is available only if MySQL was compiled using OpenSSL. The implication for MySQL distributions compiled using yaSSL is that SHA-256 passwords can be used only when clients use SSL to access the server. See Section 6.4.4, “Configuring MySQL to Use Secure Connections”.

Assuming that MySQL has been compiled using OpenSSL, the following procedure describes how to enable RSA encryption of passwords during the client connection process:

After the server has been configured with the RSA key files, clients have the option of using them to connect to the server using accounts that authenticate with the sha256_password plugin. As mentioned previously, such accounts can use either an SSL connection (in which case RSA is not used) or an unencrypted connection that encrypts the password using RSA. Assume for the following discussion that SSL is not used. Connecting to the server involves no special preparation on the client side. For example:

shell> mysql --ssl-mode=DISABLED -u sha256user -p
Enter password: Sh@256Pa33

For connection attempts by sha256user, the server determines that sha256_password is the appropriate authentication plugin and invokes it. The plugin finds that the connection does not use SSL and thus requires the password to be transmitted using RSA encryption. In this case, the plugin sends the RSA public key to the client, which uses it to encrypt the password and returns the result to the server. The plugin uses the RSA key on the server side to decrypt the password and accepts or rejects the connection based on whether the password is correct.

The server sends the public key to the client as needed, but if a copy of the RSA public key is available on the client host, the client can use it to save a round trip in the client/server protocol:

shell> mysql --ssl-mode=DISABLED -u sha256user -p --server-public-key-path=file_name

The public key value in the file named by the --server-public-key-path option should be the same as the key value in the server-side file named by the sha256_password_public_key_path system variable. If the key file contains a valid public key value but the value is incorrect, an access-denied error occurs. If the key file does not contain a valid public key, the client program cannot use it. In this case, the sha256_password plugin sends the public key to the client as if no --server-public-key-path option had been specified.

Client users can get the RSA public key two ways: