Daniel When not delving into obscure PDF or Java bugs, Daniel is exploring the new features in JavaFX.

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How to create your own test certificates and keys for signing PDF files

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From a practical point of view you need one of two sort of files in order to sign something.  Either a keystore file or a pfx file. A keystore file is basically a file representing a associated array.  The keystore needs an equivalent of a username and password so you can open it.  Each element of the map points to a list of certificates (a certificate chain).  The keys for the elements are called aliases and are represented by a string and they also have a password as well.

A Keystore file can be created fairly easily with the keytool software that comes with a Java installation. Open up whatever Java folder you have (I’m using Windows, so its in Program Files/Java) and look in either a JRE or JDK folder and you should find a keytool.exe.  To generate a keystore open a console window and type in something like:

keytool -genkey -alias myAlias -keyalg RSA -keystore \path\keystoreName

This generates a keystore called keystoreName using myAlias to identify it and encrypt it with RSA.  You’ll then get a bunch of questions to fill in starting with the password for the keystore as a whole. The last thing it asks for is a password for the entry with the certificate chain, the mapping also has the same alias as the alias specified to identify the keystore as a whole, just to keep you on your toes!

You can also generate a certificate if you feel that way inclined:

keytool -export -alias myAlias -file \path\somecert.cer -keystore \path\keystoreName

It will then ask for the keystore password and create a certificate called somecert.cer.  If you like you can double click on the certificate in Windows and it will ask to install it to your trusted certificates.

If you have a finite life span you may want to generate a .pfx file instead. In Windows open a console window, cd to somewhere sensible and type:

cipher /r:whateveryoulike.

Enter a password and you have a certificate (whateveryoulike.cert) and a .pfx file (whateveryoulike.pfx).  Ta-da!

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Daniel When not delving into obscure PDF or Java bugs, Daniel is exploring the new features in JavaFX.

2 Replies to “How to create your own test certificates and keys…”

  1. Hi Daniel,

    Could you please share some knowledge about signature in pdf via some posts ? I am a developer current get struggling to sign a pdf by the way it supports. I suppose that I have a digital Id stored in a device like a smart card, what I got from the card is a signature and a certificate (the card has a program in it to sign a message using private-key stored inside it). how do I put in into the pdf ?


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