Web-automation.ru

Решение:

public static class PasswordHasher
{
   private static SHA1Managed hasher = new SHA1Managed();
   
   public static string Hash(string password)
   {
     // convert password to byte array
     byte[] passwordBytes =
     System.Text.ASCIIEncoding.ASCII.GetBytes(password);

     // generate hash from byte array of password
     byte[] passwordHash = hasher.ComputeHash(passwordBytes);

     // convert hash to string
     return Convert.ToBase64String(passwordHash, 0, passwordHash.Length);