Create a Gravatar Link with C#

GravatarHelper.cs

    public class GravatarHelper
    {
        private string CalculateHash(string email)
        { 
            MD5 md5Hasher = MD5.Create();
 
            byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(email));

            StringBuilder sBuilder = new StringBuilder();

            for (int i = 0; i < data.Length; i++)
            {
                sBuilder.Append(data[i].ToString("x2"));
            }

            return sBuilder.ToString();
        }

        public string CreateGravatarLink(string email, bool isHttps, int size = 120)
        {
            string hash = CalculateHash(email);

            string protocol = "http";
            if (isHttps) protocol = "https";

            return $"{protocol}://www.gravatar.com/avatar/{hash}?size={size}";
        }
    }