Email Messages with Digital Signatures using S/MIME

This section provides an email message example with a digital signature using the S/MIME (Secure/Multipurpose Internet Mail Extensions) standard. The message is divided into 2 parts: the message part and the digital signature part.

Now if you want to send text message with a digital signature, you email program will use the S/MIME (Secure/Multipurpose Internet Mail Extensions) standard.

Here is an example email message using S/MIME to deliver the message and its digital signature:

Received: by sphinx (mbox mlande) (with Cubic Circle's cucipop (v1...
X-From_: bob@internet.com Wed Aug 20 19:40:22 2003 
Return-Path: <bob@internet.com> 
Received: from psmtp.com (exprod5mx37.postini.com [12.158.34.194])...
Message-Id: <200308210240.h7L2e5A0016623@sphinx.got.net> 
Received: from source ([69.9.251.177]) by exprod5mx37.postini.com ...
From: "Bob Example" <bob@internet.com>
To: "Alice Example" <alice@internet.com>
Date: Wed, 20 Aug 2003 16:02:43 -0500
Subject: Test message
MIME-Version: 1.0
Content-Type: multipart/signed;
    micalg=SHA1;
    boundary="----=_NextBoundry____Wed,_20_Aug_2003_19:25:21";
    protocol="application/pkcs7-signature"

This is a multi-part message in MIME format.

------=_NextBoundry____Wed,_20_Aug_2003_19:25:21
Content-Type: text/plain

Hello Alice.
This is a test message with 5 lines in the message body
and an digital signature.
Your friend,
Bob
------=_NextBoundry____Wed,_20_Aug_2003_19:25:21
Content-Type: application/pkcs7-signature; name=smime.p7s
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=smime.p7s

MIIDdwYJKoZIhvcNAQcCoIIDaDCCA2QCAQExCTAHBgUrDgMCGjALBgkqhkiG9w0BBw...
...
f6gkgp9Z0XtRdGimJeB/BxUCFGFFJqwYRt1WYcIOQoGiaowqGzVI
------=_NextBoundry____Wed,_20_Aug_2003_19:25:21--

Note that:

Last update: 2011.

Table of Contents

 About This Book

 Introduction of PKI (Public Key Infrastructure)

 Introduction of HTTPS (Hypertext Transfer Protocol Secure)

 Using HTTPS with IE (Internet Explorer) 10

 Using HTTPS with Chrome 40

 Using HTTPS with Firefox 35

 Perl Scripts Communicating with HTTPS Servers

 PHP Scripts Communicating with HTTPS Servers

 Java Programs Communicating with HTTPS Servers

 Certificate Stores and Certificate Console

 .NET Programs Communicating with HTTPS Servers

 CAcert.org - Root CA Offering Free Certificates

 PKI CA Administration - Issuing Certificates

 Digital Signature - Microsoft Word 2007

 Digital Signature - OpenOffice.org 3

S/MIME and Email Security

 What Is S/MIME?

 Digital Signature Scheme for Email Messages

 A Simple Email Message Example

 Email Messages with Attachments using MIME

Email Messages with Digital Signatures using S/MIME

 Encrypted Email Messages using S/MIME

 Digital Signature and Encryption in Outlook 2007

 Email Security Settings in Outlook 2007

 Valid Certificate Required in Outlook 2007

 Message Security Properties in Outlook 2007

 Firefox Extension - Gmail S/MIME

 PKI (Public Key Infrastructure) Terminology

 Outdated Tutorials

 References

 PDF Printing Version