Validation of Discourse SSO payload

Validator.cs

  private static bool IsValid(string encodedPayload, string signature)
  {
      return Hash(DISCOURSE_SECRET, encodedPayload) == signature;
  }
      
  private static string Hash(string secret, string encodedPayload)
  {
      var hasher = new HMACSHA256(Encoding.UTF8.GetBytes(secret));
      var hash = hasher.ComputeHash(Encoding.UTF8.GetBytes(encodedPayload));
      return BitConverter.ToString(hash).Replace("-", "").ToLowerInvariant();
  }