Generate self-signed x.509 certificates for use with SSL/TLS
Benefits at a glance:
- Supports multiple domain names in one cert with the SubjectAltName field
- Trivial to automate — the only required argument is a domain name
- Automatically set modern options by default (
-sha256
,-utf8
) - Easy to install
.deb
and.rpm
packages
Usage: sslfie [OPTION]... DOMAIN [DOMAIN2]...
Generate a self-signed x.509 certificate for use with SSL/TLS.
Options:
-o PATH -- output the cert to a file at PATH
-k PATH -- output the key to a file at PATH
-K PATH -- sign key at PATH (instead of generating a new one)
-c CC -- country code listed in the cert (default: XX)
-s SIZE -- generate a key of size SIZE (default: 2048)
-y N -- expire cert after N years (default: 10)
-p -- prompt for cert values
-r -- output csr instead of signing a cert
sudo add-apt-repository ppa:mkropat/ppa
sudo apt-get update
sudo apt-get install sslfie
Download the .deb
package from Latest Releases. Then run:
sudo dpkg -i sslfie*.deb
sudo apt-get install -f # if there were missing dependencies
Download the .rpm
package from Latest Releases. Then run:
sudo yum localinstall sslfie*.noarch.rpm
Installation isn't required. The sslfie
script is entirely self-contained,
so you can just download it:
curl -O https://github.com/raw/mkropat/sslfie/master/sslfie
chmod +x sslfie
Then run it like so:
./sslfie www.example.com example.com
Generate a cert for www.example.com:
$ sslfie -c US -o example.crt -k example.key www.example.com example.com
That's it. You can use openssl
to examine the generated certificate:
$ openssl x509 -in example.crt -noout -text | less
Some key lines to look for are:
Subject: C=US, CN=www.example.com
And:
X509v3 Subject Alternative Name:
DNS:www.example.com, DNS:example.com
Did you know that the steps for creating a self-signed certificate with
openssl
are almost identical to the steps for creating a certificate signing
request? I didn't when I named it sslfie
, go figure.
If you want to get a real (that is, not self-signed) certificate, sslfie
can
help you with that too:
$ sslfie -r -p -o example.csr -k example.key www.example.com example.com
The -r
option causes -o
to output a CSR instead of a cert. Also notice
we're using the -p
option, which presents a text UI for inputting the full
distinguished
name,
if you want. Important caveat for using -p
: you must use -o
and -k
to
capture the output, because using shell redirection breaks the text UI.
To examine the generated CSR:
$ openssl req -in example.crt -noout -text | less
- Certify — earlier command that functions very similarly
- (I wrote
sslfie
from scratch because I needed something that could be automated)
- (I wrote
- Creating certificates with SANs using OpenSSL — example config file
- How to generate self-signed cert by jww — good howto post
- SSL howto by Tommy M. McGuire — example of using environment variables in
openssl
config