如何使用公钥加密字符串并使用 MimeKit 使用私钥解密？答案

【问题标题】：How to encrypt string with public key and decrypt using private key using MimeKit?如何使用公钥加密字符串并使用 MimeKit 使用私钥解密？
【发布时间】：2021-04-01 18:27:35
【问题描述】：

我很难寻找有关如何使用公钥证书加密字符串并使用 Mimekit 使用私钥证书对其进行解密的解决方案。这是我使用公钥证书加密文本文件的代码：

public string encryptFile(string filename)
{
    var certificate2 = new X509Certificate2(Path.Combine(HttpContext.Current.Request.PhysicalApplicationPath, /Sample.crt));
    MimeEntity body;

    using (var content = new MemoryStream(File.ReadAllBytes(filename)))
    {
        var part = new MimePart(MimeTypes.GetMimeType(filename))
        {
            ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
            ContentTransferEncoding = ContentEncoding.Binary,
            FileName = Path.GetFileName(filename),
            Content = new MimeContent(content)
        };


        var recipient = new CmsRecipient(certificate2)
        {
            EncryptionAlgorithms = new EncryptionAlgorithm[] { EncryptionAlgorithm.TripleDes }
        };
        var recipients = new CmsRecipientCollection();
        recipients.Add(recipient);

        using (var ctx = new TemporarySecureMimeContext())
            body = ApplicationPkcs7Mime.Encrypt(ctx, recipients, part);
    }

    string response = body.ToString();
    return response;
}

但是使用这种方式，我在加密之前将要加密的字符串写入文件。我想做的是使用 MimeKit 直接加密字符串。我只是使用 MimeKit 的新手。如果有人知道我该怎么做，那将是一个很大的帮助。

【问题讨论】：

这能回答你的问题吗？ How to use public and private key encryption technique in C#
我不确定我是否理解问题所在。您说您想避免将内容写入文件，但您所做的只是将其写入文件，然后将其读回内存以便将其传递给 MimeKit。为什么不先将其写入内存，然后像现在一样将其与 MimeKit 一起使用？

标签： c# encryption mime pkcs#7 mimekit

【解决方案1】：

public string EncryptString(string value)
{
    var certificate2 = new X509Certificate2(Path.Combine(HttpContext.Current.Request.PhysicalApplicationPath, /Sample.crt));
    MimeEntity body;

    using (var content = new MemoryStream(Encoding.UTF8.GetBytes (value)))
    {
        var part = new MimePart(MimeTypes.GetMimeType(filename))
        {
            ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
            ContentTransferEncoding = ContentEncoding.Binary,
            FileName = Path.GetFileName(filename),
            Content = new MimeContent(content)
        };


        var recipient = new CmsRecipient(certificate2)
        {
            EncryptionAlgorithms = new EncryptionAlgorithm[] { EncryptionAlgorithm.TripleDes }
        };
        var recipients = new CmsRecipientCollection();
        recipients.Add(recipient);

        using (var ctx = new TemporarySecureMimeContext())
            body = ApplicationPkcs7Mime.Encrypt(ctx, recipients, part);
    }

    using (var memory = new MemoryStream ()) {
        body.WriteTo (memory);

        string response = Encoding.UTF8.GetString (memory.ToArray ());
        return response;
    }
}

【讨论】：