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Introduction(介绍)

This guide is designed to introduce the reader to the Secure Sockets Layer, (SSL) application-level protocol, and particularly the OpenSSL implementation of SSL. After a brief description of exactly what OpenSSL is, and what it is useful for, the guide will further illustrate the practical usage of OpenSSL in a client-server environment, and provide specific examples of applications which may benefit from OpenSSL. Finally, the guide will lead the user through example procedures required to use OpenSSL with the popular Apache Hyper Text Transport Protocol (HTTP) server for the purpose of serving secured web pages from your Ubuntu computer.

本指南主要是向读者介绍安全套接层,(SSL)应用级协议,以及 SSL 在 OpenSSL 上的特定实现。在简要介绍 OpenSSL 是什么,它对什么有用之后,本指南将在客户-服务器环境中举例说明 OpenSSL 的特定用法,并提供应用程序从 OpenSSL 中获利的典型示例。最后,本指南通过演示从您 Ubuntu 计算机要求使用带 OpenSSL 的 Apache 超文本传输协议(HTTP)服务器提供安全 web 页服务的步骤。

Target Audience(阅读对象)

To properly implement the practical steps found in this guide, the reader should be a user of Ubuntu who is comfortable with the use command-line applications, using the Bourne Again SHell (bash) environment, and editing system configuration files with their preferred text editor application. While previous familiarity with Server Sockets Layer, (SSL) or the OpenSSL implementation in particular is not required for this guide, the reader is advised to pursue further learning from the resources listed in the Resources section of this guide in order to broaden understanding of this powerful security layer if desired.

为了更好的部署本向导中的实践步骤,读者最好是Ubuntu的用户,能熟练使用命令行,运用bash环境,以及能使用自己喜欢的文本编辑器来编辑系统配置文件。对于是否精通SSL或者是否有OpenSSL实践经验在本向导中并不重要,建议读者阅读在资源区域中学习以便加深自己对这种强大的安全技术的理解。

About OpenSSL(关于OpenSSL)

Secure Sockets Layer is an application-level protocol which was developed by the Netscape Corporation for the purpose of transmitting sensitive information, such as Credit Card details via the Internet. SSL works by using a private key to encrypt data transferred over the SSL-enabled connection, thus thwarting eavesdropping of the information. The most popular use of SSL is in conjunction with web browsing with HTTP, but many network applications can benefit from using SSL. By convention, URLs that require an SSL connection start with https: instead of http:.

安全套接层是一种应用层协议,它由网景公司为了传输某些敏感信息而开发的,比如在因特网上传输信用卡的细节。SSL使用一个私钥来加密数据,从而使数据能在开启SSL的连接中传输,避免被窃听。SSL最常用的地方就是在HTTP协议的web浏览中使用,但很多其他网络应用也可以从使用SSL中得到好处。按照惯例,使用SSL的URL以https:打头,而不是http:。

OpenSSL is a robust, commercial-grade implementation of SSL tools, and related general purpose library based upon SSLeay, developed by Eric A. Young and Tim J. Hudson. OpenSSL is available as an Open Source equivalent to commercial implementations of SSL via an Apache-style license.

OpenSSL是一种健壮的、商业级的SSL工具,与建立在SSLeay(由Eric A. Young和Tim J. Hudson开发)基础上的普通库文件相关。OpenSSL可以通过开源方式或者基于Apache-style license的商业应用来获得。

About X.509(关于 X.509)

X.509 is a specification for digital certificates published by the International Telecommunications Union - Telecommunication (ITU-T). It specifies information and attributes required for the identification of a person or a computer system, and is used for secure management and distribution of digitally signed certificates across secure Internet networks. OpenSSL most commonly uses X.509 certificates.

X.509是由国际电讯联盟——电讯(ITU-T)发布的一种规范。它规定了个人或个人计算机在身份验证上的信息和属性,用来对因特网上传输的电子签署认证进行安全管理和发布。OpenSSL大多数情况下使用X.509认证。

Practical OpenSSL Usage(OpenSSL的使用)

Basic OpenSSL Commands(基本OpenSSL命令)

The following section of the guide presents some of the more common basic commands, and parameters to commands which are part of the OpenSSL toolkit. For additional information, read the various OpenSSL system manual pages with the man command, and refer to the information presented in the Resources section of this guide.

本向导的以下部分展现了一些OpenSSL工具组中最常用的基本命令,以及命令的参数。如果需要额外的信息,请使用man命令阅读各种OpenSSL系统手册,或者参考向导的资源部分。

Determine installed OpenSSL version:

确定已经安装的OpenSSL版本:

openssl version

List of available OpenSSL sub-commands:

列出可使用的OpenSSL子命令:

openssl help

Get additional help information on OpenSSL sub-commands by using the openssl command followed by the sub-command, and the -h switch. For example, to get additional information on the openssl enc sub-command:

使用openssl,加上子命令,再加上-h参数,来获得OpenSSL子命令的使用方法。比如需要获得openssl enc的使用方法:

openssl enc -h

List all available cipher algorithms:

列出所有cipher算法:

openssl ciphers -v

You may benchmark your computer's speed with OpenSSL, measuring how many bytes per second can be processed for each algorithm, and the times needed for sign/verify cycles by using the following command:

如果需要使用OpenSSL测试计算机速度,每个算法每秒能处理多少字节,以及签署/验证周期的时间,使用以下命令:

openssl speed

SSL Certificates(SSL认证)

The following sections of this guide will introduce the concepts involved in the generation and use of SSL certificates, both the self-signed variety, and those signed by a recognized certificate authority for use with a server application supporting SSL, and the use of X.509 certificates in client applications.

SSL Certificates for Server Use

Once you have properly generated an X.509-compliant SSL certificate, you may either elect to sign the certificate yourself, by generating a Certificate Authority (CA), or you may opt to have a globally recognized Certificate Authority sign the certificate. When the certificate is signed, it is then ready to be used with the OpenSSL toolkit, or the library to enable encrypted SSL connections to a Lightweight Directory Access Protocol, (LDAP) or Hyper Text Transport Protocol (HTTP) server, for example. This section of the guide describes the certificate generation, and signing process for both self-signed, and recognized CA-signed certificates.

Generating and Signing Self-Signed Certificates

Self-signed certificates have a major advantage in that they are completely free to use, and may be generated, signed, and used on an as-needed basis. Self-signed certificates are great for use in closed lab environments, or for testings purposes. One of the drawbacks of using self-signed certificates however, is that warnings through web browser, and other applications will be generated when accessing servers using SSL with self-signed certificates because the certificates are not signed using a globally recognized, and trusted Certificate Authority, but importing the server's root certificate into the client application, if possible, will squelch these warnings as demonstrated later in this guide. Using self-signed certificates in a publicly-accessible, production environment is not recommended due to the implicit trust issues arising from these warnings, and potential confusion to users.

IconsPage?action=AttachFile&do=get&target=IconNote.png NOTE: You must obtain a certificate signed by a recognized Certificate Authority in order to establish a commercial site, e.g. for conducting "e-commerce".

Provided you've installed the OpenSSL toolkit previously, or per instructions above, the generation of X.509 SSL certificates is quite simple. For self-signed certificates, you must first establish a Certificate Authority (CA) by following the steps below:

Creating the Certificate Authority

First, create an initial working environment, for example within your home directory by issuing the following command from a terminal prompt:

cd && mkdir -p myCA/signedcerts && mkdir myCA/private && cd myCA

The above command will place you in a newly-created subdirectory of your home directory named myCA and within this subdirectory, you should have two additional subdirectories, named signedcerts and private.

Within this initial working environment, the significance of the subdirectories, and their contents is as follows:

  • ~/myCA : contains CA certificate, certificates database, generated certificates, keys, and requests
  • ~/myCA/signedcerts : contains copies of each signed certificate
  • ~/myCA/private : contains the private key.

Next, create an initial certificate database in the ~/myCA subdirectory with the following command at a terminal prompt:

echo '01' > serial && touch index.txt

Now create an initial caconfig.cnf file suitable for the creation of CA certificates. Using your favorite editor, edit the file ~/myCA/caconfig.cnf, and insert the following content into the file:

# My sample caconfig.cnf file.
#
# Default configuration to use  when one
# is not provided on the command line.
#
[ ca ]
default_ca      = local_ca
#
#
# Default location  of  directories  and
# files needed to generate certificates.
#
[ local_ca ]
dir             = /home/<username>/myCA
certificate     = $dir/cacert.pem
database        = $dir/index.txt
new_certs_dir   = $dir/signedcerts
private_key     = $dir/private/cakey.pem
serial          = $dir/serial
#
#
# Default   expiration   and  encryption
# policies for certificates.
#
default_crl_days        = 365
default_days            = 1825
default_md              = md5
#
policy          = local_ca_policy
x509_extensions = local_ca_extensions
#
#
# Default policy to use  when generating
# server   certificates.  The  following
# fields  must  be defined in the server
# certificate.
#
[ local_ca_policy ]
commonName              = supplied
stateOrProvinceName     = supplied
countryName             = supplied
emailAddress            = supplied
organizationName        = supplied
organizationalUnitName  = supplied
#
#
# x509 extensions to use when generating
# server certificates.
#
[ local_ca_extensions ]
subjectAltName          = DNS:alt.tradeshowhell.com
basicConstraints        = CA:false
nsCertType              = server
#
#
# The default root certificate
# generation policy.
#
[ req ]
default_bits    = 2048
default_keyfile = /home/<username>/myCA/private/cakey.pem
default_md      = md5
#
prompt                  = no
distinguished_name      = root_ca_distinguished_name
x509_extensions         = root_ca_extensions
#
#
# Root  Certificate  Authority   distinguished
# name.  Change these fields to match
# your local environment!
#
[ root_ca_distinguished_name ]
commonName              = MyOwn Root Certificate Authority
stateOrProvinceName     = NC
countryName             = US
emailAddress            = root@tradeshowhell.com
organizationName        = Trade Show Hell
#
[ root_ca_extensions ]
basicConstraints        = CA:true

IconsPage?action=AttachFile&do=get&target=IconWarning3.png IMPORTANT: Make sure to adjust the obvious site-specific details in the file, such as the two instances of /home/<username>/, commonName, organizationName, etc. to personalize for your environment. For more information on the directives contained within this configuration file, use the man config command.

When you've edited the file to match your environment, save the file as ~/myCA/caconfig.cnf.

Next, you need to generate the Certificate Authority Root Certificate and Key using the following commands:

export OPENSSL_CONF=~/myCA/caconfig.cnf

The previous command sets an environment variable OPENSSL_CONF which forces the openssl tool to look for a configuration file in an alternative location (in this case, ~/myCA/caconfig.cnf).

Generate the CA certificate and key with the following command:

openssl req -x509 -newkey rsa:2048 -out cacert.pem -outform PEM -days 1825

You should be prompted for a passphrase, and see output similar to this:

Generating a 2048 bit RSA private key
.................................+++
.................................................................................................+++
writing new private key to '/home/bshumate/myCA/private/cakey.pem'
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:
-----

Do not forget the passphrase used with the command above! You'll need it every time you want to generate and sign a new server or client certificate!

The above process will create a self-signed certificate using PEM format and RSA public/private key encryption. The certificate will be valid for 1825 days. The location, and purpose of the resultant files is as follows:

  • ~/myCA/cacert.pem : CA public certificate
  • ~/myCA/private/cakey.pem : CA private key
Creating a Self-Signed Server Certificate

Now that you have a Certificate Authority configured, you may use it to sign self-signed certificates. Prior to beginning the steps below, you may wish to decide whether or not you want to encrypt the Certificate private key with a passphrase. The advantages of encrypting the key with a passphrase include protection of the certificate in the event it is stolen.

The certificate cannot be used with SSL-enabled applications without entering the passphrase every time the SSL-enabled application is started. This condition, while being most secure, can present a problem: If the server must be started in an unattended manner as in the case of a computer restart, then no one will be available to enter the passphrase, and subsequently the server will not start. One way to eliminate this condition involves a trade-off in security:

The key may be decrypted however, to remove the passphrase necessity, and thus SSL-enabled applications will then start automatically, without need to enter a passphrase.

To actually generate a self-signed certificate for use with an SSL application, follow this process:

Create the server configuration file, by editing ~/myCA/exampleserver.cnf with your favorite text editor. Add this example content:

#
# exampleserver.cnf
#

[ req ]
prompt                  = no
distinguished_name      = server_distinguished_name

[ server_distinguished_name ]
commonName              = tradeshowhell.com
stateOrProvinceName     = NC
countryName             = US
emailAddress            = root@tradeshowhell.com
organizationName        = My Organization Name
# The organizationalUnitName field maybe NOT valid in some
# version of openssl, like 1.0.1.  If you get errors, try comment
# out the line below.
organizationalUnitName  = Subunit of My Large Organization

Be sure to change the values under server_distinguished_name especially the commonName value. The commonName value must match the host name, or CNAME for the host you wish to use the key for. If the commonName does not match the intended hostname, then host / certificate mismatch errors will appear in the client applications of clients attempting to access the server.

Once you've edited the file appropriately, save it as ~/myCA/exampleserver.cnf. Generate the server certificate, and key with the following commands:

export OPENSSL_CONF=~/myCA/exampleserver.cnf

The previous command sets an environment variable OPENSSL_CONF which forces the openssl tool to look for a configuration file in an alternative location (in this case, ~/myCA/exampleserver.cnf).

Now generate the certificate, and key:

openssl req -newkey rsa:1024 -keyout tempkey.pem -keyform PEM -out tempreq.pem -outform PEM

You should be prompted for a passphrase, and see output similar to this:

Generating a 1024 bit RSA private key
...++++++
...............++++++
writing new private key to 'tempkey.pem'
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:
-----

Don't forget the passphrase!

Next, you may translate the temporary private key into an unencrypted key by using the following command:

openssl rsa < tempkey.pem > server_key.pem

You should be prompted for the passphrase used above, and see the following output:

Enter pass phrase:
writing RSA key

If you wish to leave the key encrypted with a passphrase, simply rename the temporary key using the following command, instead of following the step above:

mv tempkey.pem server_key.pem

IconsPage?action=AttachFile&do=get&target=IconTip.png Remember: If you use a server key encrypted with a passphrase, the passphrase will have to be entered each time the server application using the encrypted key is started. This means the server application will not start unless someone, or something enters the key.

Now you need to sign the server certificate with the Certificate Authority (CA) key using these commands:

export OPENSSL_CONF=~/myCA/caconfig.cnf

The previous command modifies the environment variable OPENSSL_CONF which forces the openssl tool to look for a configuration file in an alternative location (in this case, ~/myCA/caconfig.cnf to switch back to the CA configuration).

Then sign the certificate as follows:

openssl ca -in tempreq.pem -out server_crt.pem

You will be prompted for the passphrase of the CA key as created in the Certificate Authority setup from above. Enter this passphrase at the prompt, and you will then be prompted to confirm the information in the exampleserver.cnf, and finally asked to confirm signing the certificate. Output should be similar to this:

Using configuration from /home/bshumate/myCA/caconfig.cnf
Enter pass phrase for /home/bshumate/myCA/private/cakey.pem:
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
commonName            :PRINTABLE:'tradeshowhell.com'
stateOrProvinceName   :PRINTABLE:'NC'
countryName           :PRINTABLE:'US'
emailAddress          :IA5STRING:'root@tradeshowhell.com'
organizationName      :PRINTABLE:'Trade Show Hell'
organizationalUnitName:PRINTABLE:'Black Ops'
Certificate is to be certified until Jan  4 21:50:08 2011 GMT (1825 days)
Sign the certificate? [y/n]:y


1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated

Remove the temporary certificate, and key files with the following command:

rm -f tempkey.pem && rm -f tempreq.pem

Congratulations! You now have a self-signed server application certificate, and key pair:

  • server_crt.pem : Server application certificate file
  • server_key.pem : Server application key file

Use the documentation provided with the server application you wish to use the certificate, and key for in order to properly use it. See the Configuring Apache for SSL Support section below for an example usage.

Optional Step for Certain Server Applications

Some server applications, such as the Courier IMAP mail server application require that the unencrypted private key be prepended to the server certificate. To accomplish this, simply enter the following commands:

cat server_key.pem server_crt.pem > hold.pem
mv      hold.pem server_crt.pem
chmod   400      server_crt.pem
Converting X.509 Certificates to PKCS#12 for Client Applications

If you wish to generate PKCS#12 certificates from your server's Root CA X.509 certificate for client use, you will need to use the following process on the particular server certificate, and key pair you desire to export a client certificate for:

Create a single file containing both the certificate, and key with the following command:

openssl req -x509 -nodes -days 365 -newkey rsa:1024 -keyout mycert.pem -out mycert.pem

Then, convert this certificate / key combination file into the PKCS#12 certificate with the following command:

openssl pkcs12 -export -out mycert.pfx -in mycert.pem -name "Certificate for Whatever"

You will be prompted for an Export password, which you may use, or just leave blank.

The resultant mycert.pfx file may now be imported into applications such as Web Browsers, and E-Mail clients. Since this certificate represents the Root CA certificate of your server, all subsequent server-level certificates signed by the CA certificate will also be automatically accepted by the client application which installs this PKCS#12 version of the certificate.

Generating Certificate for Signing by Recognized CA

In order to run a production server which will engage in commercial activity, such as "e-commerce", it is required to generate a certificate, and have it signed by a recognized Certificate Authority (CA) such as VeriSign. The process for generating a certificate request, and obtaining a certificate signed by a recognized CA can be difficult. You must complete all requisite "paperwork" prior to creating a certificate request, and ensure all required information is accurate.

Assuming you do not wish a passphrase-encrypted key, enter the following command to generate the private key, and certificate request:

openssl req -new -newkey rsa:1024 -nodes -keyout mykey.pem -out myreq.pem

If you already have a key you wish to use, then use the following command instead:

openssl req -new -key mykey.pem -out myreq.pem

You may wish to verify the signature, and information contained in the certificate request. Verify the signature with this command:

openssl req -in myreq.pem -noout -verify -key mykey.pem

and verify the information with this command:

openssl req -in myreq.pem -noout -text

The next steps typically involve pasting the content of the certificate request file into the CA's signup form, and awaiting the certificate. Also, you should safeguard the key file, as it will be required to use the certificate you receive from the CA.

Using PKCS#12 Certificates in Client Applications

This section of the guide explains using PKCS#12 certificates for SSL connections from the client perspective, and demonstrates the process of importing certificates into the Firefox Web Browser applications, and a couple of the more popular E-Mail clients.

Importation of a root certificate into such applications enables a trusted SSL-encrypted connection to the server from whence the certificate came, free of nagging messages about the certificate being self-signed, and so on.

Importing a Certificate into Mozilla Firefox

Importation of a PKCS#12 certificate into the Mozilla Firefox Web Browser application is very simple:

  • From within Firefox, click Edit > Preferences
  • Click the Advanced icon
  • Click the View Certificates button
  • Click the Import button
  • Browse to the location of the certificate file, which is typically a .pfx file type
  • Highlight the certificate file, and click the Open button
  • You may be prompted to enter Firefox's Master Password at this point, or to set an initial Master Password. Enter the current, or net password as required, confirm it, and click OK
  • You will then be prompted to enter the certificate's Export password. If there is no such password attached to the certificate, simply click OK, otherwise enter the password, and click OK
  • A message will appear advising that Firefox has "Successfully restored your security certificate(s) and private key(s)"
  • Click OK
  • You have successfully imported the server's client PKCS#12 certificate into Firefox
Importing a Certificate into Evolution

Importation of a PKCS#12 certificate into the Evolution E-Mail client couldn't be simpler:

  • From within Evolution, click Edit > Preferences
  • Click the Certificates icon
  • Click the Import button
  • Browse to the location of the certificate file, which is typically a .pfx file type
  • Highlight the certificate file, and click the Open button
  • You may be prompted to enter Evolution's certificate database password at this point, or to set an initial certificate database password. Enter the current, or new password as required, confirm it, and click OK
  • You will then be prompted to enter the PKCS12 File Password. If there is no such password attached to the certificate, simply click OK, otherwise enter the password, and click OK
  • You should see the certificate, and its details appear in the Your Certificates section of the Evolution Settings window
  • Click the Close button
  • You have successfully imported the server's client PKCS#12 certificate into Evolution
Importing a Certificate into Mozilla Thunderbird

Importation of a PKCS#12 certificate into the Mozilla Thunderbird E-Mail client application is very simple:

  • From within Thunderbird, click Edit > Preferences
  • Click the Advanced icon
  • Click the Certificates entry in the right pane
  • Click the Manage Certificates button
  • Click the Import button
  • Browse to the location of the certificate file, which is typically a .pfx file type
  • Highlight the certificate file, and click the Open button
  • You may be prompted to enter Thunderbird's Master Password at this point, or to set an initial Master Password. Enter the current, or new password as required, confirm it, and click OK
  • You will then be prompted to enter the certificate's Export password. If there is no such password attached to the certificate, simply click OK, otherwise enter the password, and click OK
  • A message will appear advising that Thunderbird has "Successfully restored your security certificate(s) and private key(s)"
  • Click OK
  • You have successfully imported the server's client PKCS#12 certificate into Thunderbird
Importing a Certificate into the System-Wide Certificate Authority Database

You can import a CA Certificate into the system-wide database of trusted certificate authorities. Applications that use this database will automatically trust any certificates stored here.

1. Copy your certificate to the system certificate directory. At a terminal prompt, type:

$ sudo cp mycert.pem /usr/share/ca-certificates/mycert.crt

2. Edit the ca-certificates configuration file /etc/ca-certificates.conf. Add the name of the file you copied to /use/share/ca-certificates to the top of the list just after the final "#". For example:

# This file lists certificates that you wish to use or to ignore to be
# installed in /etc/ssl/certs.
# update-ca-certificates(8) will update /etc/ssl/certs by reading this file.
#
# This is autogenerated by dpkg-reconfigure ca-certificates.
# certificates shoule be installed under /usr/share/ca-certificates
# and files with extension '.crt' is recognized as available certs.
#
# line begins with # is comment.
# line begins with ! is certificate filename to be deselected.
#
mycert.crt
brasil.gov.br/brasil.gov.br.crt
cacert.org/cacert.org.crt
mozilla/ABAecom_=sub.__Am._Bankers_Assn.=_Root_CA.crt
[... many additional certificates omitted ...]

3. Update the CA certificates database by typing:

$ sudo update-ca-certificates

4. You have successfully imported your certificate into the system CA certificates database.

Configuring Apache for SSL Support

This section of the guide will describe the procedure for configuring the Apache2 HTTP server to provide HTTPS connections using OpenSSL. This is fairly straightforward, and simple process.

Install Apache 2

Install the Apache 2 HTTP server by installing the following package apache2

Generate a Server Certificate

The simplest method of generating a self-signed SSL certificate for Apache 2 use is to make use of the apache2-ssl-certificate shell script which is bundled with the Ubuntu Apache 2 package. This shell script uses a specific configuration file (/usr/share/apache2/ssleay.cnf) and parameters to generate a self-signed certificate with no passphrase encryption of the key element. To generate an Apache 2 certificate with the script, simply use the following command at a terminal prompt:

sudo apache2-ssl-certificate

Answer all of the questions which are asked, and you should then observe the creation of an apache.pem in the /etc/apache2/ssl directory.

Next you must enable SSL support in the Ubuntu Apache 2 package by executing the following command:

sudo a2enmod ssl

You should receive the following output from the above command:

Module ssl installed; run /etc/init.d/apache2 force-reload to enable.

Now configure SSL settings for Apache 2 by creating a new ssl enabled site configuration file, and adjusting the directory locations as needed for HTTP and HTTPS instances of Apache 2:

sudo cp /etc/apache2/sites-available/default /etc/apache2/sites-available/ssl
sudo ln -s /etc/apache2/sites-available/ssl /etc/apache2/sites-enabled/ssl

Edit /etc/apache2/sites-enabled/ssl, and modify the NameVirtualHost * directive to resemble:

NameVirtualHost *:443

and the VirtualHost * directive to resemble:

<VirtualHost *:443>

Add the following two lines under the <VirtualHost *:443> line:

SSLEngine On
SSLCertificateFile /etc/apache2/ssl/apache.pem

You can also configure the DocumentRoot and Directory directives as needed.

Edit /etc/apache2/sites-enabled/default

Edit /etc/apache2/sites-enabled/ssl, and modify the NameVirtualHost * directive to resemble:

NameVirtualHost *:80

and the VirtualHost * directive to resemble:

<VirtualHost *:80>

You can also configure the DocumentRoot and Directory directives as needed.

Edit /etc/apache2/ports.conf and add the line:

Listen 443

under the existing Listen 80 line.

Reload Apache 2 so that the new configuration directives take effect, with the command:

sudo /etc/init.d/apache2 force-reload

You should now have a functional, SSL-enabled Apache 2 HTTP/HTTPS server.

Redirecting HTTP traffic to HTTPS

If you want to force users to use HTTPS, you can redirect all HTTP traffic to the HTTPS site. This is a great method because it is transparent to the users, they don't have do anything different.

First, you must enable URL rewrite support in the Ubuntu Apache 2 package by executing the following command:

sudo a2enmod rewrite

You should receive the following output from the above command:

Module rewrite installed; run /etc/init.d/apache2 force-reload to enable.

Next, edit /etc/apache2/sites-enabled/default, and add the following three lines under the <VirtualHost *:80> line:

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

Now reload Apache 2 so that the new configuration directives take effect, with the command:

sudo /etc/init.d/apache2 force-reload

You are all done! Users who go to the HTTP (port 80) site will now be redirected to HTTPS and all traffic will be encrypted.

Resources

Additional resources pertaining to OpenSSL and Secure Sockets Layer appear below.

Local System Resources

man config System manual page for the OpenSSL library configuration files
man gendsa System manual page for the gendsa DSA private key generator
man genrsa System manual page for the genrsa RSA private key generator
man openssl System manual page for the openssl command-line tool
man rand System manual page for the rand pseudo-random byte generator utility
man x509 System manual page for the x509 certificate display and signing utility

WWW Resources

CACert, a FREE X.509 Certificate Authority

Creating a Certificate Authority (CA)

OpenSSL Certificate Authority Setup

OpenSSL Website

Public Key Infrastructure (X.509) (pkix)