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The Ethics of Decompilation
If decompilation is possible to a certain
extent, is it then also allowed?
Decompilation can be used for a number of reasons, including:
However, not all uses of decompilers are legal uses.
- Recovery of lost source code (by accident or via a disgruntled
- Migration of applications to a new hardware platform,
- Translation of code written in obsolete languages not supported
by compiler tools nowadays,
- Determination of the existence of viruses or malicious code in
the program, and
- Recovery of someone else's source code (to determine an algorithm
Throughout the world, computer programs are protected by
copyright law. Copyright protects the expression of an
idea in the form of a program, hence protecting the developer's
(or company's) intellectual property on the software.
Copyright law provides a bundle of exclusive rights to the software
developer, among others, the right to reproduce and make adaptations
to the developed computer program.
It is a breach of these rights the making of reproductions and
adaptations without permission of the copyright holder.
Further, license agreements may also bind the user to operate
the program in a certain way and to avoid using decompilation
or disassembly techniques on that program.
Different countries have different exceptions to the copyright
owner's rights or precedent has been established in court proceedings.
This means that these uses are allowed by law.
The most common ones are:
Not all countries implement the same laws, you should contact
your lawyer if in doubt.
- Decompilation/disassembly for the purposes of interoperability
(to another piece of software or hardware) where the interface
specification has not been made available,
- Decompilation/disassembly for the purposes of error correction
where the owner of the copyright is not available to make
the correction, and
- To determine parts of the program that are not protected by
copyright (e.g. algorithms), without breach of other forms of
protection (e.g. patents or trade secrets).
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