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c#x509certificate
Victor Sanchez
Victor Sanchez

Reputation: 650

Reading RFC822 field from certificate

I have this certificate:

Windows Certificate

I need read field "RFC822". I use X509Certificate2 class, but this class don't return this information:

StringBuilder sb = new StringBuilder();
X509Certificate2 card = GetCertificate();                    

sb.AppendLine(card.FriendlyName);
sb.AppendLine(card.GetCertHashString());
sb.AppendLine(card.GetEffectiveDateString());
sb.AppendLine(card.GetExpirationDateString());
sb.AppendLine(card.GetExpirationDateString());
sb.AppendLine(card.GetFormat());
//sb.AppendLine(card.GetIssuerName());
sb.AppendLine(card.GetKeyAlgorithm());
sb.AppendLine(card.GetKeyAlgorithmParametersString());
//sb.AppendLine(card.GetName());
sb.AppendLine(card.GetPublicKeyString());
sb.AppendLine(card.GetRawCertDataString());
sb.AppendLine(card.GetSerialNumberString());
sb.AppendLine(card.HasPrivateKey.ToString());
sb.AppendLine(card.Issuer);
sb.AppendLine(card.IssuerName.Name);
sb.AppendLine(card.SerialNumber);
sb.AppendLine(card.Subject);
sb.AppendLine(card.SubjectName.Name);
sb.AppendLine(card.Thumbprint);
sb.AppendLine(card.Version.ToString());

Can I read RFC822 data from .NET program?

Thanks

Upvotes: 0

Views: 2076

Answers (1)

Mehmet Ataş
Mehmet Ataş

Reputation: 11559

You can get bytes of a Subject Alternative Name extension by 

byte[] subjAltName = cert.Extensions["2.5.29.17"].RawData

If you look at these bytes by System.Text.Encoding.UTF8.GetString(subjAltName) you will see email address. But this byte array actually represents an ASN.1 Sequence structure and needs to be decoded properly. As Eugene stated it may be easier to use a third party library which encapsulates complex ASN.1 stuff if you need some deep information inside a certificate.

Upvotes: 2

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