1. Network Security: Lab#4-1 E-mail Security J. H. Wang Dec. 3, 2013

2. Objectives To learn to use e-mail security tools –PGP To learn the availability of email security libraries –S/MIME –DKIM

3. Packages & Libraries in this Lab Packages –GPG4win: for Windows Libraries –OpenDKIM

4. Experiment Scenario Signing/verification of files using certificates –Create a new certificate –Encrypt/sign the file “original.txt” into another file “enc.txt” (using sender’s certificate) –Then, we decrypt/verify it and get another file “dec.txt” (using sender’s certificate), and check if the decrypted file is the same as the original file Sending/receiving e-mails with certificates –Set up email account –Read mails –Send mails

5. GnuPG Privacy Guard Homepage: http://www.gnupg.org/http://www.gnupg.org/ Version: –1.4.15 (portable standalone version) –2.0.22 (enhanced version, harder to build) Platforms: Linux/FreeBSD/Windows/MacOS X An implementation of OpenPGP Installation steps –(skipped)

6. GPG4win Homepage: http://www.gpg4win.org/http://www.gpg4win.org/ Latest version: 2.2.1 OpenPGP: an open standard for e-mail security (RFC 4880) –S/MIME also included Installation steps: –Simply follow the instructions on screen

7. Other Tools Included in GPG4win Kleopatra: GnuPG certificate manager –New certificate –Encrypting/Signing a file –Decrypting/Verifying a file Claws Mail: a mail reader –Setting up your mail account –Reading mails –Sending mails

8. Microsoft Outlook Support in GPG4win PGP for Outlook –GpgOL 1.0 can support OpenPGP and S/MIME

9. Configuring Outlook for S/MIME Configure Your Personal Email Certificates Send a Signed Message Read a Signed Message Check the Credentials of a Signed Message Send an Encrypted Message Read an Encrypted Message Get Certificates for Other Users

10. OpenDKIM Homepage: http://www.opendkim.org/http://www.opendkim.org/ –Latest version: opendkim 2.8.4 –C library for DKIM service: libmilter –Also a milter-based filter application: opendkim Can plug in to any milter-based MTAs: Sendmail, PostFix An open source implementation for IETF DKIM standard (RFC 6376) based on dkim-milter from Sendmail –Library: libdkim –Milter: dkim-milter 2.8.3 (plugins to sendmail) Also includes implementations of –ADSP (Author Domain Signing Practises): RFC 5617 –VBR (Vouch by Reference): RFC 5518

11. Configuration and Installation Compilation of opendkim –Download opendkim-2.8.4.tar.gz – tar -xzvf opendkim-2.8.4.tar.gz – cd opendkim-2.8.4 –./configure – make – make install Configuration of opendkim –For signing and verification Install opendkim and configure your MTA

12. Summary Email security –PGP –S/MIME –DKIM