ENCRIPTACIÓN SHA-1 (C#)

using System.Security;
using System.Security.Cryptography; 

public string HashString(string str) 
{
     SHA1 sha1 = SHA1Managed.Create();
     ASCIIEncoding encoding = new ASCIIEncoding();
     byte[] stream = null;
     StringBuilder sb = new StringBuilder();
     stream = sha1.ComputeHash(encoding.GetBytes(str));
     for (int i = 0; i < stream.Length; i++) sb.AppendFormat("{0:x2}", stream[i]);


     return sb.ToString(); 
}