Reference : http://www.kindblad.com/2009/03/how-to-generate-sha-1-hash-of-string.html
How to generate the SHA-1 hash of a string using C#
The namespace System.Security.Cryptography contains classes for working with cryptography such as hashing. Within this namespace you will find the SHA1Managed class which we can utilize to generate the SHA-1 hash of a string. Below you will find a helper method using this class:
public static string GetSha1(string value)
{
var data = Encoding.ASCII.GetBytes(value);
var hashData = new SHA1Managed().ComputeHash(data);
var hash = string.Empty;
foreach (var b in hashData)
hash += b.ToString("X2");
return hash;
}