Authentication Plugin - PARSEC

PARSEC is a modern, secure authentication plugin that uses salted passwords and elliptic curve cryptography to prevent replay attacks and secure user credentials.

This plugin is available from MariaDB 11.6.

The PARSEC Authentication Plugin is intended to be the default in a future release.

The PARSEC (Password Authentication using Response Signed with Elliptic Curve) authentication plugin uses salted passwords, key derivation, extensible password storage format, and both server- and client-side scrambles.

It signs the response with ed25519, but it uses stock unmodified ed25519 as provided by OpenSSL/WolfSSL/GnuTLS.

Description

• The KDF function is pbkdf2 (supported by everything, including windows native, Java, javascript, PHP, .NET.

• Parameters to the pbkdf2 are stored in with authentication plugin data : hash function (SHA512,SHA256), iteration count, salt, key_length, together with derived key = PBKDF2(func, password, salt, iteration_count, key_length).

• The number of iterations is a power of two, at least 1024. From MariaDB 13.1, it is configurable through the parsec_iterations system variable.

• The algorithm is ed25519, "hash" is the public key generated using ed25519 from the PBKDF2(password).

The authentication string, stored by the server, is this:

concat('P', conv(log2(iterations)-10, 10, 62), ':', base64(salt), ':', base64(hash))

For example, it looks like this: P0:WW9sXaaL/o:vubFBzIrapbfHct1/J72dnUryz5VS7lA6XHH8sIx4TI

• It consists of colon-separated fields.

• The first field is 'P' (denotes KDF algorithm = PBKDF2) and the number of iterations, '0' means 1024, '1' means 2048, etc.

• This is followed by the salt.

• This is followed by the password hash.

The first two fields together are called ext-salt, extended salt.

Login Process, Packet Exchange

1. The server sends an Authentication Switch Request with a 32-byte random scramble.

2. The client sends an empty packet to the server to request the ext-salt.

3. The server sends the ext-salt to the client.

4. The client sends the random 32-byte scramble, and the concat(server scramble, client scramble) ed25519-signed by a secret key generated from the function PBKDF2(password, ext-salt).

5. The server replies with "ok" or "access denied".

Installing

If you run into the error ERROR 1524 (HY000): Plugin 'parsec' is not loaded it means you need to install the authentication plugin first. You can do it on a running server with:

INSTALL SONAME 'auth_parsec';

There is no need to pass additional command-line options or have config files to keep the PARSEC authentication method available. Running the INSTALL SONAME once is enough and the MariaDB Server will remember it even if server is restarted or upgraded.

Example

CREATE USER test1@'%' IDENTIFIED VIA parsec USING PASSWORD('pwd');

Configuring the Number of Iterations

The parsec_iterations system variable is available from MariaDB 13.1.

The number of PBKDF2 iterations used to derive the key from a password is controlled by the parsec_iterations system variable. A higher value increases the cost of deriving the key, which strengthens resistance to brute-force attacks at the expense of more work per authentication.

The iteration count is baked into an account's stored credentials when its password is set. The value in effect at that time — the session value if set, otherwise the global value — is the one recorded for the account. Changing parsec_iterations afterwards does not alter existing accounts; they keep the iteration count they were created with until their password is set again.

SET SESSION parsec_iterations = 262144;
CREATE USER test1@'%' IDENTIFIED VIA parsec USING PASSWORD('pwd');

The value must be a power of two. If a value that is not a power of two is supplied, it is rounded up to the next power of two and a warning is issued:

SET GLOBAL parsec_iterations = 5000;

Warning (1231): parsec_iterations rounded up to 8192

parsec_iterations

• Description: Number of iterations used when generating the key corresponding to the password (PBKDF2-HMAC-SHA512). Rounded up to a power of two. This variable is only available when the PARSEC plugin is loaded.

• Commandline: --parsec-iterations=#

• Scope: Global, Session

• Dynamic: Yes

• Data Type: INT UNSIGNED

• Default Value: 1024

• Minimum Value: 1024

• Maximum Value: 1073741824

• Introduced: MariaDB 13.1

Future

PARSEC is currently available in latest MariaDB versions, but not installed or used by default yet. Once MDEV-12320 is implemented, MariaDB plans to start using PARSEC as the default password authentication method.

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