How is a ViewState generated from XAML data in the first method described?

The first method constructs XAML data (e.g., for command execution or writing a webshell), then serializes it using Microsoft.PowerShell.Editor.dll to obtain serialized XAML bytes. The signature is computed by combining the serialized data with the generator bytes and applying HMACSHA1 with the validationKey. Finally, the serialized data and signature are concatenated and Base64-encoded to form the ViewState, with complete implementation available in the open-source project linked in the article.