Function inferAlgorithm

http/unstable_message_signatures.ts:309–335

(key: CryptoKey)

}

function inferAlgorithm(key: CryptoKey): SignatureAlgorithm {
  const alg = key.algorithm;
  const name = alg.name;
  if (name === "Ed25519") return "ed25519";
  if (name === "HMAC") {
    const hash = (alg as HmacKeyAlgorithm).hash.name;
    if (hash === "SHA-256") return "hmac-sha256";
    throw new TypeError(`Unsupported HMAC hash: "${hash}"`);
  }
  if (name === "RSA-PSS") {
    const hash = (alg as RsaHashedKeyAlgorithm).hash.name;
    if (hash === "SHA-512") return "rsa-pss-sha512";
    throw new TypeError(`Unsupported RSA-PSS hash: "${hash}"`);
  }
  if (name === "RSASSA-PKCS1-v1_5") {
    const hash = (alg as RsaHashedKeyAlgorithm).hash.name;
    if (hash === "SHA-256") return "rsa-v1_5-sha256";
    throw new TypeError(`Unsupported RSASSA-PKCS1-v1_5 hash: "${hash}"`);
  }
  if (name === "ECDSA") {
    const curve = (alg as EcKeyAlgorithm).namedCurve;
    if (curve === "P-256") return "ecdsa-p256-sha256";
    if (curve === "P-384") return "ecdsa-p384-sha384";
    throw new TypeError(`Unsupported ECDSA curve: "${curve}"`);
  }
  throw new TypeError(`Cannot infer signature algorithm from key: "${name}"`);
}

// =============================================================================
// Component Value Resolution