HMAC digest encoding

test.php

$signature_from_header = file_get_contents("example-signature.txt");
$webhook_secret = file_get_contents("example-secret.txt");
$raw_data = file_get_contents("example-payload.json");

// Uses the bitmask value for json encode
// JSON_UNESCAPED_SLASHES => 64
// JSON_UNESCAPED_UNICODE => 256
$json_data = json_encode(json_decode($raw_data),320);

print($json_data);
print("\n");

$calculated_sig = "sha1=" . hash_hmac("sha1", $json_data, $webhook_secret);

print("Calculated Signature: " . $calculated_sig . "\n");

$matching = $calculated_sig == $signature_from_header ? "true" : "false";

print("Matching: " . $matching);