Function getHmacSha256

src/cmap/auth/aws4.ts:44–63

(key: string | Uint8Array, str: string)

 * @returns Uint8Array containing the HMAC-SHA256 digest.
 */
const getHmacSha256 = async (key: string | Uint8Array, str: string): Promise<Uint8Array> => {
  let keyData: Uint8Array;
  if (typeof key === 'string') {
    keyData = stringToBuffer(key);
  } else {
    keyData = key;
  }

  const importedKey = await crypto.subtle.importKey(
    'raw',
    keyData,
    { name: 'HMAC', hash: { name: 'SHA-256' } },
    false,
    ['sign']
  );
  const strData = stringToBuffer(str);
  const signature = await crypto.subtle.sign('HMAC', importedKey, strData);
  const digest = new Uint8Array(signature);
  return digest;
};

/**
 * Converts header values according to AWS requirements,