private Multipart Sign(Multipart input, GpgPrivateKeyInfo senderKey)
{
var gpgMultipart = new Multipart("signed");
gpgMultipart.ContentType.Parameters.Add("micalg", "pgp-sha256");
gpgMultipart.ContentType.Parameters.Add("protocol", "application/pgp-signature");
gpgMultipart.Add(input);
var multipartStream = new MemoryStream();
input.WriteTo(multipartStream);
var signedText = Encoding.UTF8.GetString(multipartStream.ToArray()).Replace("\n", "\r\n");
_gpg.Sign(signedText, out string signatureText, senderKey.Id, SignatureType.DetachSign, true, senderKey.Passphrase);
var signaturePart = new TextPart("pgp-signature");
signaturePart.ContentType.MediaType = "application";
signaturePart.ContentType.Name = "signature.asc";
signaturePart.ContentDisposition = new ContentDisposition("attachment");
signaturePart.ContentDisposition.FileName = "signature.asc";
signaturePart.Text = signatureText;
signaturePart.ContentTransferEncoding = ContentEncoding.SevenBit;
signaturePart.Headers.Remove(HeaderId.ContentTransferEncoding);
gpgMultipart.Add(signaturePart);
return(gpgMultipart);
}
private Multipart EncryptAndSign(Multipart input, GpgPrivateKeyInfo senderKey, GpgPublicKeyInfo recipientKey)
{
var gpgMultipart = new Multipart("encrypted");
gpgMultipart.ContentType.Parameters.Add("protocol", "application/pgp-encrypted");
var versionPart = new TextPart("pgp-encrypted");
versionPart.ContentType.MediaType = "application";
versionPart.Headers.Add(new Header("Content-Description", "PGP/MIME version identification"));
versionPart.Text = "Version: 1";
gpgMultipart.Add(versionPart);
var multipartStream = new MemoryStream();
input.WriteTo(multipartStream);
multipartStream.Position = 0;
var plainText = Encoding.UTF8.GetString(multipartStream.ToArray()).Replace("\n", "\r\n");
_gpg.EncryptAndSign(plainText, out string cipherText, recipientKey.Id, senderKey.Id, true, senderKey.Passphrase);
var encryptedPart = new TextPart("octet-stream");
encryptedPart.ContentType.MediaType = "application";
encryptedPart.ContentType.Name = "encrypted.asc";
encryptedPart.ContentDisposition = new ContentDisposition("inline");
encryptedPart.ContentDisposition.FileName = "encrypted.asc";
encryptedPart.Text = cipherText;
encryptedPart.ContentTransferEncoding = ContentEncoding.SevenBit;
encryptedPart.Headers.Remove(HeaderId.ContentTransferEncoding);
gpgMultipart.Add(encryptedPart);
return(gpgMultipart);
}
public MimeMessage Create(InternetAddress from, InternetAddress to, GpgPrivateKeyInfo senderKey, GpgPublicKeyInfo recipientKey, string subject, Multipart content)
{
if (senderKey != null && recipientKey != null)
{
content = EncryptAndSign(content, senderKey, recipientKey);
}
else if (recipientKey != null)
{
content = Encrypt(content, recipientKey);
}
else if (senderKey != null)
{
content = Sign(content, senderKey);
}
var message = new MimeMessage();
message.From.Add(from);
message.To.Add(to);
message.Subject = subject;
message.Body = content;
return(message);
}
public void Send(InternetAddress from, InternetAddress to, GpgPrivateKeyInfo senderKey, GpgPublicKeyInfo recipientKey, string subject, Multipart content)
{
Send(Create(from, to, senderKey, recipientKey, subject, content));
}
public void Send(InternetAddress to, GpgPrivateKeyInfo senderKey, GpgPublicKeyInfo recipientKey, string subject, Multipart content)
{
Send(MailboxAddress.Parse(_config.SystemMailAddress), to, senderKey, recipientKey, subject, content);
}