Like the others have said, there are many options.
Here is some sample code (using MD5 instead of SHA) from Microsoft that might help get you get started
using System; using System.Security.Cryptography; using System.Text; string sSourceData; byte[] tmpSource; byte[] tmpHash; sSourceData = "MySourceData"; //Create a byte array from source data. tmpSource = ASCIIEncoding.ASCII.GetBytes(sSourceData); //Compute hash based on source data. tmpHash = new MD5CryptoServiceProvider().ComputeHash(tmpSource);