How do you parse the Subject Alternate Names from an X509Certificate2?

Question

Is there an easy way to get the Subject Alternate Names from an X509Certificate2 object?

        foreach (X509Extension ext in certificate.Extensions)
               


        

Answer 1

Solution to all Languages .NET
This solution is an improvement of Minh Nguyen above solution so it can work in all Languages

private static List GetSujectAlternativeName(X509Certificate2 cert)
        {
            var result = new List();


            var subjectAlternativeName = cert.Extensions.Cast()
                                                .Where(n => n.Oid.Value== "2.5.29.17") //n.Oid.FriendlyName=="Subject Alternative Name")
                                                .Select(n => new AsnEncodedData(n.Oid, n.RawData))
                                                .Select(n => n.Format(true))
                                                .FirstOrDefault();

            if (subjectAlternativeName != null)
            {
                var alternativeNames = subjectAlternativeName.Split(new[] { "\r\n", "\r", "\n" }, StringSplitOptions.None);

                foreach (var alternativeName in alternativeNames)
                {
                    var groups = Regex.Match(alternativeName, @"^(.*)=(.*)").Groups; // @"^DNS Name=(.*)").Groups;

                    if (groups.Count > 0 && !String.IsNullOrEmpty(groups[2].Value))
                    {
                        result.Add(groups[2].Value);
                    }
                }
            }

            return result;
        }