S / Mime String Encryption
I was tasked with encrypting a string using S / Mime encryption. Eons ago, the company I work for bought a component for this (from IPWorks), but we had untold beams of grief and the component played well on our servers. No problem with functionality, more licenses.
So, I have to do it myself. I broke through MSDN and forums and put together the following code. Unfortunately, the result it produces is not what I expect. Lots of Korean and special characters I didn't expect.
public string EncryptString(string toEncrypt, string key)
{
// Convert the body to bytes
byte[] bodyBytes = Encoding.ASCII.GetBytes(toEncrypt);
// Encrypt the body
var envelopedCms = new EnvelopedCms(new ContentInfo(bodyBytes));
var certificate = new X509Certificate2(Encoding.ASCII.GetBytes(key));
var recipient = new CmsRecipient(certificate);
envelopedCms.Encrypt(recipient);
byte[] encryptedBytes = envelopedCms.Encode();
var msg = new MailMessage();
var ms = new MemoryStream(encryptedBytes);
var av = new AlternateView(ms, "application/pkcs7-mime; smime-type=enveloped-data;name=smime.p7m; content-transfer-encoding=Base64; content-disposition=attachment; fileName=smime.p7m;");
msg.AlternateViews.Add(av);
return new StreamReader(msg.AlternateViews[0].ContentStream).ReadToEnd();
}
Can anyone see an obvious error here?
I am not "married" to this code, so if you have an alternative suggestion on how I can do this please go through.
Kindness and gratitude,
Dan
source to share
This line is the problem:
var av = new AlternateView(ms, "application/pkcs7-mime; smime-type=enveloped-data;name=smime.p7m; content-transfer-encoding=Base64; content-disposition=attachment; fileName=smime.p7m;");
You are dumping the values of multiple headers into the Content-Type header.
Instead, you need something more:
var contentType = new ContentType ("application/pkcs7-mime; smime-type=enveloped-data; name=smime.p7m");
var attachment = new Attachment (ms, contentType);
attachment.ContentDisposition.FileName = "smime.p7m";
attachment.TransferEncoding = TransferEncoding.Base64;
However, I'm working on a much more advanced MIME library than System.Net.Mail (it's so poorly designed that it could only be designed for the complete amateur at Microsoft). This library is called MimeKit and I have already started working on S / MIME support.
source to share