Rebex.Mail 8.0.9797

Rebex Mail - The C# MIME and S/MIME library for .NET

Rebex Mail is a .NET library for creating, loading, saving, encrypting, decrypting, signing, and verifying email messages. It provides both a high-level MailMessage API and a low-level MIME & S/MIME API. Supports EML (MIME) and Outlook MSG formats.

Rebex Mail is the core assembly of Rebex Mail Pack. To send and receive messages, use protocol-specific packages: Rebex.Smtp, Rebex.Imap, Rebex.Pop3, Rebex.Ews, or Rebex.Graph for Microsoft 365.

20+ years of active development. Rebex Mail has been continuously developed and maintained since 2006, with regular updates and new features.

Key features

• MIME and MailMessage - create, load, save, and manipulate email messages in EML and Outlook MSG formats
• S/MIME encryption and signing - encrypt, decrypt, sign, and verify messages using X.509 certificates with RSA/OAEP, RSA/PSS, AES/GCM, ChaCha20/Poly1305
• Attachments and embedded objects - file attachments, embedded images, linked resources, embedded messages
• Outlook MSG files - read and write .MSG files with MAPI property access
• SMTP - send messages via SMTP with TLS/SSL (via Rebex.Smtp)
• IMAP - access mailboxes, search, and manage messages and folders (via Rebex.Imap)
• POP3 - download messages from a mail server (via Rebex.Pop3)
• EWS - access Microsoft Exchange mailboxes (via Rebex.Ews)
• Microsoft Graph - access Exchange Online / Microsoft 365 mailboxes (via Rebex.Graph)
• Cryptographic algorithms including PQC - ML-KEM, ML-DSA, Ed25519, ChaCha20/Poly1305, AES/GCM, ECDH, ECDSA, RSA, and more
• FIPS 140-3 compliant mode

Getting started

Create and save an email message

// create mail message
var message = new Rebex.Mail.MailMessage();

// fill some fields
message.From = "alice@example.org";
message.To = "bob@example.org";
message.Subject = "Test";

// add text and HTML bodies
message.BodyText = "This is plain-text body.";
message.BodyHtml = "This is <strong>HTML</strong> body.";

// save message in EML format
message.Save(@"C:\MyData\mail.eml");

// save message in Outlook MSG format
message.Save(@"C:\MyData\mail.msg", MailFormat.OutlookMsg);

Add attachments

// create mail
var mail = new Rebex.Mail.MailMessage();
mail.From = "alice@example.org";
mail.To = "bob@example.org";
mail.Subject = "Report";
mail.BodyText = "Please find the report attached.";

// add an attachment
mail.Attachments.Add(new Attachment(@"C:\MyData\report.pdf"));

Sign a message (S/MIME)

// create mail
var mail = new Rebex.Mail.MailMessage();
// fill some fields
// ...

// load certificate with private key
Certificate signer = Certificate.LoadPfx(@"C:\MyData\certificate.pfx", "password");

// sign the mail
mail.Sign(signer);

Encrypt a message (S/MIME)

// create mail
var mail = new Rebex.Mail.MailMessage();
// fill some fields
// ...

// load receiver's certificate (public key is enough for encryption)
Certificate recipient = Certificate.LoadDer(@"C:\MyData\ReceiverCertificate.der");

// encrypt the message
mail.Encrypt(recipient);

Validate signature and decrypt

// load a mail
var mail = new Rebex.Mail.MailMessage();
mail.Load(@"C:\MyData\mail.eml");

// validate signature
if (mail.IsSigned)
{
    MailSignatureValidity result = mail.ValidateSignature();
    Console.WriteLine(result.Valid ? "Signature is valid." : "Signature is not valid.");
}

// decrypt
if (mail.IsEncrypted && mail.CanDecrypt)
{
    mail.Decrypt();
}

Embed images into HTML messages

// create mail
var mail = new Rebex.Mail.MailMessage();
mail.From = "alice@example.org";
mail.To = "bob@example.org";
mail.Subject = "Report with chart";

// generate a content ID for the image
string imageId = "chart001@example.org";

// add HTML body with embedded image reference
mail.BodyHtml = string.Format("See the chart: <img src='cid:{0}'/>", imageId);

// add image to linked resources
var resource = new LinkedResource(@"C:\MyData\chart.jpg", MediaTypeNames.Image.Jpeg);
resource.ContentId = imageId;
mail.Resources.Add(resource);

Send a message via SMTP (Rebex.Smtp)

using (var smtp = new Rebex.Net.Smtp())
{
    smtp.Connect(hostname, SslMode.Explicit);
    smtp.Login(username, password);

    smtp.Send(sender, recipient, "Test", "Hello World!");

    smtp.Disconnect();
}

Download messages via IMAP (Rebex.Imap)

using (var imap = new Rebex.Net.Imap())
{
    imap.Connect("imap.example.org", SslMode.Implicit);
    imap.Login(username, password);

    imap.SelectFolder("INBOX");

    // get list of unread messages
    ImapMessageCollection list = imap.Search(ImapSearchParameter.Unread);

    foreach (ImapMessageInfo info in list)
    {
        Console.WriteLine("From: {0}, Subject: {1}", info.From, info.Subject);
    }

    imap.Disconnect();
}

Download messages via POP3 (Rebex.Pop3)

using (var pop3 = new Rebex.Net.Pop3())
{
    pop3.Connect("pop.example.org", SslMode.Implicit);
    pop3.Login(username, password);

    Pop3MessageCollection list = pop3.GetMessageList();
    foreach (Pop3MessageInfo info in list)
    {
        MailMessage mail = pop3.GetMailMessage(info.SequenceNumber);
        // process the mail ...
    }

    pop3.Disconnect();
}

Access Exchange via EWS (Rebex.Ews)

using (var client = new Rebex.Net.Ews())
{
    client.Connect(hostname, SslMode.Implicit);
    client.Login(username, password);

    // get list of unread messages
    var list = client.Search(
        EwsFolderId.Inbox,
        EwsSearchParameter.IsRead(false));

    foreach (EwsMessageInfo info in list)
    {
        Console.WriteLine("From: {0}, Subject: {1}", info.From, info.Subject);
    }

    client.Disconnect();
}

Access Microsoft 365 via Graph (Rebex.Graph)

using (var client = new Rebex.Net.GraphClient())
{
    client.Connect();
    client.Login(token);

    // get list of unread messages from Inbox
    var unread = GraphMessageSearchParameter.IsRead(false);
    GraphMessageCollection messages = client.Search(GraphFolderId.Inbox, unread);

    foreach (GraphMessageInfo info in messages)
    {
        Console.WriteLine("From: {0}, Subject: {1}", info.From, info.Subject);
    }

    client.Disconnect();
}

Supported platforms

• .NET 10 on Windows, Linux, macOS, Android, iOS/tvOS
• .NET 9 on Windows, Linux, macOS, Android, iOS/tvOS
• .NET 8 on Windows, Linux, macOS, Android, iOS/tvOS
• .NET 7 on Windows, Linux, macOS, Android, iOS/tvOS
• .NET 6 on Windows, Linux, macOS
• .NET 5 on Windows, Linux, macOS
• .NET Framework 4.0, 4.5.x, 4.6.x, 4.7.x, 4.8.x
• .NET Framework 3.5 SP1
• .NET Core 3.1 on Windows, Linux, macOS
• Xamarin.Android (10.1 and higher; via .NET Standard 2.1)
• Xamarin.iOS (13.10 and higher; via .NET Standard 2.1)
• Mono 6.0 or higher on Linux and macOS

Supported architectures: x86, x64, AMD64.

Licensing

This is a paid commercial product with a free 30-day trial.

• Trial mode: Start your free 30-day trial by generating your trial key
• Licensed mode: Buy Rebex Mail Pack and get your full license key

When the full license key is provided, NuGet.org repository can be used to retrieve versions of Rebex components covered by your support contract.

Support

Talk to real people. No scripted or AI responses. Support is provided directly by the engineers who design and build the library.

Email us at support@rebex.net or visit rebex.net/support.

Documentation

• API reference
• MIME and MailMessage
• S/MIME - secure mail
• Outlook MSG files
• SMTP library
• IMAP library
• POP3 library
• EWS library
• Graph library
• TLS/SSL core
• X.509 certificates aspx)
• Standards and platforms