Software Plug-In for the Signature Creation Step


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You will need a basic knowledge of Java and a good understanding of the technology of digital signatures and using private keys.


This techniques allows you to substitute the section of code that accesses the private signing key and creates the RSA signature. A source code example is given below.


This technique can be used to access your smart card. The plug-in can be constructed to use your smart card vendor's drivers to perform these basic signature functions.

Design summary:

  • You provide a Java class written with a specific name. This class is added to the run time classpath.
  • The IP-Protector attempts to load this class if it exists.
  • When a signature is created, then a user warning dialog will appear (screen shot)
  • The pre-processing by IP-Protector before your code is executed includes: SHA-1 hash generation and creates a data structure ready to be signed (the signed attributes). Your processing can include displaying the signed document hash value.
  • Invoke the Java code that you provide (PkSigner.class)
  • Your code calculates the signature by accessing a private key. Your code returns the signature and the associated public key certificate.
  • Post-processing by IP-Protector verifies the signature and displays the results.


For your testing of this technique, you can use the installation approach that does not use Java Web Start that is described here.  You would add your PkSigner.class to the classpath.

Example of a plug-in

This source code is provided as a means for you to easily use this plug-in replacement technique. This example uses the PKCS#12 and RSA signature libraries contained in Sun Microsytems Java version 1.3 and later.


Download example : overrideEG.zip

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