Fixed DigitalCertificate.DnsNames to return unicode domain names

Author: jstedfast

MimeKit/Cryptography/BouncyCastleCertificateExtensions.cs

@@ -202,6 +202,9 @@ static string[] GetSubjectAlternativeNames (X509Certificate certificate, int tag
 		/// </exception>
 		public static string GetSubjectEmailAddress (this X509Certificate certificate, bool idnEncode = false)
 		{
+			if (certificate == null)
+				throw new ArgumentNullException (nameof (certificate));
+
 			var address = certificate.GetSubjectNameInfo (X509Name.EmailAddress);
 
 			if (string.IsNullOrEmpty (address)) {
@@ -233,6 +236,9 @@ public static string GetSubjectEmailAddress (this X509Certificate certificate, b
 		/// </exception>
 		public static string[] GetSubjectDnsNames (this X509Certificate certificate, bool idnEncode = false)
 		{
+			if (certificate == null)
+				throw new ArgumentNullException (nameof (certificate));
+
 			var domains = GetSubjectAlternativeNames (certificate, GeneralName.DnsName);
 
 			if (idnEncode) {

MimeKit/Cryptography/SecureMimeDigitalCertificate.cs

@@ -130,7 +130,7 @@ public string Fingerprint {
 		/// </remarks>
 		/// <value>The email address.</value>
 		public string Email {
-			get { return Certificate.GetSubjectEmailAddress (true); }
+			get { return Certificate.GetSubjectEmailAddress (false); }
 		}
 
 		/// <summary>
@@ -141,7 +141,7 @@ public string Email {
 		/// </remarks>
 		/// <value>The DNS name.</value>
 		public string[] DnsNames {
-			get { return Certificate.GetSubjectDnsNames (true); }
+			get { return Certificate.GetSubjectDnsNames (false); }
 		}
 
 		/// <summary>

MimeKit/Cryptography/WindowsSecureMimeDigitalCertificate.cs

@@ -140,7 +140,7 @@ public string Email {
 		/// </remarks>
 		/// <value>The DNS name.</value>
 		public string[] DnsNames {
-			get { return Certificate.GetSubjectDnsNames (true); }
+			get { return Certificate.GetSubjectDnsNames (false); }
 		}
 
 		/// <summary>