As of MySQL 5.6.6, MySQL provides an authentication plugin that implements SHA-256 hashing for user account passwords.
To connect to the server using an account that authenticates
sha256_password plugin, you must
use either an SSL connection or an unencrypted connection that
encrypts the password using RSA, as described later in this
section. Either way, use of the
sha256_password plugin requires that MySQL
be built with SSL capabilities. See
Section 6.3.10, “Using SSL for Secure Connections”.
The following table shows the plugin names on the server and client sides.
Table 6.10 MySQL SHA-256 Authentication Plugin
|Server-side plugin name|
|Client-side plugin name|
|Library object file name||None (plugins are built in)|
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.
Create the account and specify that it authenticates using
CREATE USER 'sha256user'@'localhost' IDENTIFIED WITH sha256_password;
SET old_passwords = 2; SET PASSWORD FOR 'sha256user'@'localhost' = PASSWORD('Sh@256Pa33');
Alternatively, start the server with the default authentication
plugin set to
sha256_password. For example,
put these lines in the server option file:
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 '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
Another consequence of using
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
PASSWORD to set the account password. For example, to
mysql_native_password plugin, do
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
sha256_password plugin, be sure
that the value of
is 2 before using
old_passwords has a value
other than 2, an error occurs for attempts to set the password:
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
Section 5.1.4, “Server System Variables”, and
Section 12.13, “Encryption and Compression Functions”.
MySQL can be compiled using either OpenSSL or yaSSL (see
Section 22.214.171.124, “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
It is possible for the client to transmit passwords to the server using RSA encryption during the client connection process, as described later.
The server exposes two additional system variables,
It is intended that the database administrator will set
these to the names of the RSA private and public key-pair
files at server startup if the key files have names that
differ from the system variable default values.
The server exposes a status variable,
displays the RSA public key value.
The mysql and
mysqltest client programs support a
option for specifying an RSA public key file explicitly.
(This option was added in MySQL 5.6.6 under the name
--server-public-key and renamed in 5.6.7 to
For clients that use the
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
If an SSL connection is used, the password is sent as cleartext but cannot be snooped because the connection is encrypted using SSL.
If an SSL connection is not used but RSA encryption is available, the password is sent within an unencrypted connection, but the password is RSA-encrypted to prevent snooping. When the server receives the password, it decrypts it. A scramble is used in the encryption to prevent repeat attacks.
If an SSL connection is not used and RSA encryption is not
causes the connection attempt to fail because the password
cannot be sent without being exposed as cleartext.
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 126.96.36.199, “Configuring MySQL to Use SSL 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:
Create the RSA private and public key-pair files using the instructions in Section 6.3.11, “Creating SSL and RSA Certificates and Keys”.
If the private and public key files are located in the data
directory and are named
public_key.pem (the default values
system variables), the server will use them automatically at
Otherwise, in the server option file, set the system variables to the key file names. If the files are located in the server data directory, you need not specify their full path names:
[mysqld] sha256_password_private_key_path=myprivkey.pem sha256_password_public_key_path=mypubkey.pem
If the key files are not located in the data directory, or to make their locations explicit in the system variable values, use full path names:
[mysqld] sha256_password_private_key_path=/usr/local/mysql/myprivkey.pem sha256_password_public_key_path=/usr/local/mysql/mypubkey.pem
Restart the server, then connect to it and check the
variable value. The value will differ from that shown here,
but should be nonempty:
SHOW STATUS LIKE 'Rsa_public_key'\G*************************** 1. row *************************** Variable_name: Rsa_public_key Value: -----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDO9nRUDd+KvSZgY7cNBZMNpwX6 MvE1PbJFXO7u18nJ9lwc99Du/E7lw6CVXw7VKrXPeHbVQUzGyUNkf45Nz/ckaaJa aLgJOBCIDmNVnyU54OT/1lcs2xiyfaDMe8fCJ64ZwTnKbY2gkt1IMjUAB5Ogd5kJ g8aV7EtKwyhHb0c30QIDAQAB -----END PUBLIC KEY-----
If the value is empty, the server found some problem with the key files. Check the error log for diagnostic information.
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:
mysql --ssl=0 -u sha256user -pEnter password:
For connection attempts by
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:
mysql --ssl=0 -u sha256user -p --server-public-key-path=
The public key value in the file named by the
should be the same as the key value in the server-side file
named by the
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
had been specified.
Client users can get the RSA public key two ways:
The database administrator can provide a copy of the public key file.
A client user who can connect to the server some other way
can use a
SHOW STATUS LIKE
'Rsa_public_key' statement and save the returned
key value in a file.
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