PHP

Compute JWK Thumbprint for RSA and EC Public Keys

See more ECC Examples

Demonstrates how to compute a JSON Web Key thumbprint for a public key (RSA or ECC).

Note: This example requires Chilkat v9.5.0.66 or greater.

Chilkat2 PHP

<?php

use Chilkat2\PublicKey;
use Chilkat2\StringBuilder;

$pubKey = new PublicKey();

// A public key can be loaded from any format (binary DER, PEM, etc.)
// This example will load the public keys from JWK format,
// and will then compute the JWK thumbprint.

// First do it for an RSA public key...

$sb = new StringBuilder();
$sb->Append('{');
$sb->Append('"kty": "RSA",');
$sb->Append('"n": "0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAt');
$sb->Append('VT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMstn6');
$sb->Append('4tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FD');
$sb->Append('W2QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n9');
$sb->Append('1CbOpbISD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINH');
$sb->Append('aQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw",');
$sb->Append('"e": "AQAB",');
$sb->Append('"alg": "RS256",');
$sb->Append('"kid": "2011-04-29"');
$sb->Append('}');

// The JWK format is automatically detected..
try {
    $pubKey->LoadFromString($sb->GetAsString());
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Get the JWK thumbprint (using SHA256)
echo 'JWK thumbprint: ', $pubKey->GetJwkThumbprint('SHA256'), "\n";

// Output:
// JWK thumbprint: NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs

// --------------------------------------------------------------
// Now let's do an EC public key:
$sb->Clear();
$sb->Append('{ ');
$sb->Append('  "kty": "EC",');
$sb->Append('  "crv": "P-256",');
$sb->Append('  "x": "tDeeYABgKEAbWicYPCEEI8sP4SRIhHKcHDW7VqrB4LA",');
$sb->Append('  "y": "J08HOoIZ0rX2Me3bNFZUltfxIk1Hrc8FsLu8VaSxsMI"');
$sb->Append('}');

try {
    $pubKey->LoadFromString($sb->GetAsString());
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Get the JWK thumbprint (using SHA256)
echo 'JWK thumbprint: ', $pubKey->GetJwkThumbprint('SHA256'), "\n";

// Output:
// JWK thumbprint: 8fm8079s3nu4FLV_7dVJoJ69A8XCXn7Za2mtaWCnxR4