Benefits of using Viewstate are as following:-

• No server resources are required because state is in a structure in the page code.
   
• Simplicity.
   
• States are retained automatically.
   
• The values in view state are hashed, compressed, and encoded, thus representing a higher state of security than hidden fields.
   
• View state is good for caching data in Web frame configurations because the data is cached on the client.

Limitations of using Viewstate are as following: -

• Page loading and posting performance decreases when large values are stored because view state is stored in the page.
   
• Although view state stores data in a hashed format, it can still be tampered because it is stored in a hidden field on the page. The information in the hidden field can also be seen if the page output source is viewed directly, creating a potential security risk.

Below is sample code of storing values in view state.

this.ViewState["EnterTime"] = DateTime.Now.ToString();

Following is the video which demonstrates Authentication and Authorization in ASP.NET