sql.mysql.ed25519

import sql.mysql.ed25519

sql does not re-export this module, so it is reached only by importing it directly.

Ed25519 signing over a key derived from a password, which is what MariaDB’s client_ed25519 authentication is built on.

Why this is not crypto.ed25519

An ordinary Ed25519 private key is a 32 byte seed, and signing begins by hashing that seed into the 64 bytes the signature is actually computed from. MariaDB skips the seed: it hashes the password into those 64 bytes directly, so the user’s password takes the place of the expanded key rather than the place of the seed.

Nothing in crypto.ed25519 can express that, since it takes a PEM-encoded key and does its own expansion internally. So the curve arithmetic lives here, where the one thing that needs it is.

Correctness

Everything below the password derivation is Ed25519 exactly as RFC 8032 specifies it, and is checked against that document’s test vectors and against crypto.ed25519 over random keys.

Constants

P

sql.mysql.ed25519.P

The field prime, 2^255 - 19.

L

sql.mysql.ed25519.L

The order of the base point’s subgroup.

D

sql.mysql.ed25519.D

The curve constant, -121665/121666.

D2

sql.mysql.ed25519.D2

Twice the curve constant, which is what the addition uses.

Functions

password_key()

sql.mysql.ed25519.password_key(password: string) -> bytes

Expands a password into the 64 bytes MariaDB signs with.

Parameters

• password (string)

Returns bytes

public_key()

sql.mysql.ed25519.public_key(expanded) -> bytes

The public key matching an expanded key.

Parameters

• expanded (bytes) — The 64 bytes from password_key().

Returns bytes — The 32 byte encoded public key.

sign()

sql.mysql.ed25519.sign(expanded, message) -> bytes

Signs message with an expanded key.

Parameters

• expanded (bytes) — The 64 bytes from password_key().
• message (bytes)

Returns bytes — The 64 byte signature.

2026, Richard Ore and Zuri contributors