Question

我正在使用C＃.NET 4.0发送签名的SMTP邮件，如下所示：

    private void SendMailMessage(object data)
    {
        MailMessage message = new MailMessage();
        message.From = new MailAddress(fromAddress);
        message.To.Add(new MailAddress(emailTo));
        message.Subject = "Subject";
        message.IsBodyHtml = true;
        message.Body += "Blah blah blah.";
        byte[] messageBytes = Encoding.ASCII.GetBytes(message.Body);
        SignedCms Cms = new SignedCms(new ContentInfo(messageBytes));
        CmsSigner Signer = new CmsSigner(SubjectIdentifierType.IssuerAndSerialNumber, certificate);
        Cms.ComputeSignature(Signer);
        byte[] SignedBytes = Cms.Encode();
        MemoryStream signedStream = new MemoryStream(SignedBytes);
        AlternateView signedView = new AlternateView(signedStream, "application/pkcs7-mime; smime-type=signed-data;name=sig.p7m");
        message.AlternateViews.Add(signedView);
        SmtpClient client = new SmtpClient(smtpServer, int.Parse(smtpServerPort));
        client.DeliveryMethod = SmtpDeliveryMethod.Network;
        client.Send(message);
        message.Dispose();
        client = null;       
    }

据我所知，这个“有效”，如果查看消息的原始数据，我会看到备用视图中有一个大的PKCS签名。但Outlook不承认它。 Outlook客户端通常会识别已签名的邮件并尝试验证它们，并在邮件上放置一些证书以及所有这些...

我想要那......我错过了什么？

编辑：我已经在这方面取得了一些进展，但仍然遇到了一些麻烦。以下是代码的样子：

    private void SendMailMessage(string emailTo)
    {            
        MailMessage message = new MailMessage();
        message.From = new MailAddress(fromAddress);
        message.To.Add(new MailAddress(emailTo));
        message.Subject = "Special Delivery";
        message.IsBodyHtml = false;
        string body = "Content-Type: text/plain;charset=\"iso-8859-1\"\nContent-Transfer-Encoding: quoted-printable\n\nHere is some body text!";
        byte[] messageBytes = Encoding.ASCII.GetBytes(body);
        ContentInfo content = new ContentInfo(messageBytes);
        SignedCms signedCms = new SignedCms(content, false);
        CmsSigner Signer = new CmsSigner(SubjectIdentifierType.IssuerAndSerialNumber, certificate);
        signedCms.ComputeSignature(Signer);
        byte[] signedBytes = signedCms.Encode();
        MemoryStream ms = new MemoryStream(signedBytes);
        AlternateView av = new AlternateView(ms, "application/pkcs7-mime; smime-type=signed-data;name=smime.p7m");
        message.AlternateViews.Add(av);
        SmtpClient client = new SmtpClient(smtpServer, int.Parse(smtpServerPort));
        client.DeliveryMethod = SmtpDeliveryMethod.Network;
        client.Send(message);
        message.Dispose();
        client = null;
    }

值得注意的是，我留下了message.Body这次空白，只发送AlternateView。现在，当我将其发送到Outlook收件箱时，我在我的电子邮件中获得了挂锁图标，S / MIME doodad启动并尝试验证签名者，但失败了。用于签署电子邮件的证书由公开信任的CA颁发。 编辑：这是我的错，证书没有“安全电子邮件”使用属性。我会得到一张新证书。

当我将同一封电子邮件发送到Gmail地址时，我收到一条空白邮件，上面附有* .p7m附件，其中包含大量垃圾邮件。

Answer 1

在Outlook中使用此代码的代码如下所示：

private void SendMailMessage(string emailTo)
{
    MailMessage message = new MailMessage();
    message.From = new MailAddress(fromAddress);
    message.To.Add(new MailAddress(emailTo));
    message.Subject = "Regarding your lottery winnings";
    message.IsBodyHtml = false;
    string body = "Content-Type: text/plain;charset=\"iso-8859-1\"\nContent-Transfer-Encoding: quoted-printable\n\nBlah blah blah blah blah blah.";                
    byte[] messageBytes = Encoding.ASCII.GetBytes(body);
    ContentInfo content = new ContentInfo(messageBytes);
    SignedCms signedCms = new SignedCms(content, false);
    CmsSigner Signer = new CmsSigner(SubjectIdentifierType.IssuerAndSerialNumber, emailCert);
    signedCms.ComputeSignature(Signer);
    byte[] signedBytes = signedCms.Encode();
    MemoryStream ms = new MemoryStream(signedBytes);
    AlternateView av = new AlternateView(ms, "application/pkcs7-mime; smime-type=signed-data;name=smime.p7m");
    message.AlternateViews.Add(av);                
    SmtpClient client = new SmtpClient(smtpServer, int.Parse(smtpServerPort));
    client.DeliveryMethod = SmtpDeliveryMethod.Network;
    client.Send(message);
    message.Dispose();
    client = null;
}

当然，使用有效的证书。现在，当我发送此电子邮件并在Outlook中查看时，我在电子邮件中获得了证书图标，并且S / MIME控件成功验证了签名，文本显示就像我想要的那样而不向用户显示标题

请注意，我必须保留message.Body为空。把任何东西放在消息中。身体会破坏它。

让Outlook识别我的数字签名电子邮件

1 个答案: