Verify the integrity of a Knot Core zip

1. Get the published SHA256

The current hash is shown on the Knot Core page and in the manifest:

curl -sS https://knot.tools/downloads/data/releases.json | jq -r '.latest.zip_sha256'

Or through the HTTP headers when downloading:

curl -sI https://knot.tools/downloads/knot-core/latest | grep -i x-knot-sha256

2. Download the zip

curl -sSL -o knot-core.zip https://knot.tools/downloads/knot-core/latest

3. Compare locally

macOS / Linux (BSD):

shasum -a 256 knot-core.zip

Linux (GNU):

sha256sum knot-core.zip

The result must match the published zip_sha256 exactly.

4. Ed25519 signature (releases ≥ 2.13.4)

The manifest includes signature_hex and signature_payload. The signature covers the canonical JSON of the payload (not the binary content of the zip). Pinned public key: rel-2026-04.

628d5479fee21f70088115ea3dba50264d404d5a82782d6d20c781d3d27e188e

PHP example (sodium extension):

$manifest = json_decode(file_get_contents('https://knot.tools/downloads/data/releases.json'), true);
$payload = $manifest['latest']['signature_payload'];
$sig = sodium_hex2bin($manifest['latest']['signature_hex']);
$pub = sodium_hex2bin('628d5479fee21f70088115ea3dba50264d404d5a82782d6d20c781d3d27e188e');
$sort = function (array &$a) use (&$sort): void {
    ksort($a);
    foreach ($a as &$v) {
        if (is_array($v)) {
            $sort($v);
        }
    }
};
$sort($payload);
$canonical = json_encode($payload, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
var_export(sodium_crypto_sign_verify_detached($sig, $canonical, $pub));