This page runs the full SRP flow in one script: registration, login hello, authenticate, and the optional client check. The server and the client run in the same process here, so you can see every value passed between them. In a real application, each step runs in a separate request, and the values are stored and sent as described in Protocol.

use Windwalker\SRP\SRPClient;
use Windwalker\SRP\SRPServer;

$server = SRPServer::create();
$client = SRPClient::create();

$identity = '[email protected]';
$password = 'my-secret-password';

// Registration: the client sends salt and verifier only.
$pf = $client->register($identity, $password);

$salt = $pf->salt;
$verifier = $pf->verifier;

// Store identity, salt, and verifier in the user record.
// Use toBase(16) if you save them as hex strings.
$saltHex = $salt->toBase(16);
$verifierHex = $verifier->toBase(16);

Login starts with the hello request. The server reads the stored salt and verifier, and generates b and B:

// Hello: the server loads salt and verifier from storage.
$r = $server->step1($identity, $salt, $verifier);

// Keep $b in the session, not in the response.
$b = $r->secret;
$B = $r->public;

// Respond with salt and B.

The client receives salt and B, then computes its values:

$cr = $client->step1($identity, $password, $salt);

$a = $cr->secret;
$A = $cr->public;
$x = $cr->hash;

$cp = $client->step2($identity, $salt, $A, $a, $B, $x);

$K = $cp->key;
$M1 = $cp->proof;

The client sends identity, A, and M1 to the server. The server verifies the proof, and returns M2:

// Authenticate: the server loads $b and $B from the session.
$sp = $server->step2(
    $identity,
    $salt,
    $verifier,
    $A,
    $B,
    $b,
    $M1,
);

$M2 = $sp->proof;

// Clear $b and $B from the session now.

Finally, the client checks M2. This step is optional:

$client->step3($A, $K, $M1, $M2);

// No exception means the server proved it knows the verifier.
echo "Login succeeded.";

Reading the Result

Each step returns a result object:

• EphemeralResult: secret and public values, and the password hash x on the client step 1. Returned by step1().
• ProofResult: key (K), proof (M1 on the client, M2 on the server), and preMasterSecret (S). Returned by step2().
• PasswordFile: salt and verifier. Returned by register().

WARNING

Discard $a, $b, and $S after the flow completes. Keep only the session key $K if your application needs one, and handle it as a secret.