Improves certificates HOWTO

* adds links to various related documents.
* fixes a few typos.
* rewords a few sentences.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit 67472bd82b)
This commit is contained in:
Alok Menghrajani 2014-11-30 19:21:31 -08:00 committed by Richard Levitte
parent 58191465ef
commit beef278bd7

View file

@ -3,22 +3,22 @@
1. Introduction
How you handle certificates depend a great deal on what your role is.
How you handle certificates depends a great deal on what your role is.
Your role can be one or several of:
- User of some client software
- User of some server software
- User of some client application
- User of some server application
- Certificate authority
This file is for users who wish to get a certificate of their own.
Certificate authorities should read ca.txt.
Certificate authorities should read https://www.openssl.org/docs/apps/ca.html.
In all the cases shown below, the standard configuration file, as
compiled into openssl, will be used. You may find it in /etc/,
/usr/local/ssl/ or somewhere else. The name is openssl.cnf, and
is better described in another HOWTO <config.txt?>. If you want to
use a different configuration file, use the argument '-config {file}'
with the command shown below.
/usr/local/ssl/ or somewhere else. By default the file is named
openssl.cnf and is described at https://www.openssl.org/docs/apps/config.html.
You can specify a different configuration file using the
'-config {file}' argument with the commands shown below.
2. Relationship with keys
@ -29,24 +29,26 @@ somewhere. With OpenSSL, public keys are easily derived from private
keys, so before you create a certificate or a certificate request, you
need to create a private key.
Private keys are generated with 'openssl genrsa' if you want a RSA
private key, or 'openssl gendsa' if you want a DSA private key.
Further information on how to create private keys can be found in
another HOWTO <keys.txt?>. The rest of this text assumes you have
a private key in the file privkey.pem.
Private keys are generated with 'openssl genrsa -out privkey.pem' if
you want a RSA private key, or if you want a DSA private key:
'openssl dsaparam -out dsaparam.pem 2048; openssl gendsa -out privkey.pem dsaparam.pem'.
The private keys created by these commands are not passphrase protected;
it might or might not be the desirable thing. Further information on how to
create private keys can be found at https://www.openssl.org/docs/HOWTO/keys.txt.
The rest of this text assumes you have a private key in the file privkey.pem.
3. Creating a certificate request
To create a certificate, you need to start with a certificate
request (or, as some certificate authorities like to put
it, "certificate signing request", since that's exactly what they do,
they sign it and give you the result back, thus making it authentic
according to their policies). A certificate request can then be sent
to a certificate authority to get it signed into a certificate, or if
you have your own certificate authority, you may sign it yourself, or
if you need a self-signed certificate (because you just want a test
certificate or because you are setting up your own CA).
To create a certificate, you need to start with a certificate request
(or, as some certificate authorities like to put it, "certificate
signing request", since that's exactly what they do, they sign it and
give you the result back, thus making it authentic according to their
policies). A certificate request is sent to a certificate authority
to get it signed into a certificate. You can also sign the certificate
yourself if you have your own certificate authority or create a
self-signed certificate (typically for testing purpose).
The certificate request is created like this:
@ -55,12 +57,14 @@ The certificate request is created like this:
Now, cert.csr can be sent to the certificate authority, if they can
handle files in PEM format. If not, use the extra argument '-outform'
followed by the keyword for the format to use (see another HOWTO
<formats.txt?>). In some cases, that isn't sufficient and you will
have to be more creative.
<formats.txt?>). In some cases, -outform does not let you output the
certificate request in the right format and you will have to use one
of the various other commands that are exposed by openssl (or get
creative and use a combination of tools).
When the certificate authority has then done the checks the need to
do (and probably gotten payment from you), they will hand over your
new certificate to you.
The certificate authority performs various checks (according to their
policies) and usually waits for payment from you. Once that is
complete, they send you your new certificate.
Section 5 will tell you more on how to handle the certificate you
received.
@ -68,11 +72,12 @@ received.
4. Creating a self-signed test certificate
If you don't want to deal with another certificate authority, or just
want to create a test certificate for yourself. This is similar to
creating a certificate request, but creates a certificate instead of
a certificate request. This is NOT the recommended way to create a
CA certificate, see ca.txt.
You can create a self-signed certificate if you don't want to deal
with a certificate authority, or if you just want to create a test
certificate for yourself. This is similar to creating a certificate
request, but creates a certificate instead of a certificate request.
This is NOT the recommended way to create a CA certificate, see
https://www.openssl.org/docs/apps/ca.html.
openssl req -new -x509 -key privkey.pem -out cacert.pem -days 1095
@ -93,13 +98,13 @@ certificate and your key to various formats, most often also putting
them together into one file. The ways to do this is described in
another HOWTO <formats.txt?>, I will just mention the simplest case.
In the case of a raw DER thing in PEM format, and assuming that's all
right for yor applications, simply concatenating the certificate and
right for your applications, simply concatenating the certificate and
the key into a new file and using that one should be enough. With
some applications, you don't even have to do that.
By now, you have your cetificate and your private key and can start
using the software that depend on it.
By now, you have your certificate and your private key and can start
using applications that depend on it.
--
Richard Levitte