[OSM-legal-talk] Reverse-Engineering Maps and Share-Alike Licences

[Gervase Markham]

The question has been raised in these discussions about the ODbL's 
reverse-engineering provisions, and their compatibility or otherwise 
with share-alike licenses. Here is my analysis and suggestions.

1) The ODbL wishes to prevent people regenerating the Database from 
Produced Works.

ODbL section 4.7:

"For the avoidance of doubt, creating a Produced Work, and then 
re-creating the whole or a Substantial part of the Data found in this 
Database, a Derivative Database, or a Database that is part of a 
Collective Database from the Produced Work, is still subject to this 
Licence. Any product of this type of reverse engineering activity 
(whether done by You or on Your behalf by a third party) is governed by 
this License."

2) Share-Alike Licences, such as the GPL and CC-BY-SA, have clauses 
which prevent someone distributing a work under the licence from adding 
additional restrictions. (Other classes of licences may also have such a 
stipulation, but this is the largest and most common class which does.)

GPLv3 section 10:

"You may not impose any further restrictions on the exercise of the 
rights granted or affirmed under this License."

CC-BY-SA section 4a:

"You may not offer or impose any terms on the Work that restrict the 
terms of this License or the ability of the recipient of the Work to 
exercise the rights granted to that recipient under the terms of the 
License."

3) In order for the ODbL's restriction on reverse engineering to stick, 
the no-reverse-engineering stipulation has to be part of the terms which 
apply to the use or reuse of the Produced Work, both by the person who 
Produced it and by other third parties. Otherwise, the term would be 
trivially avoidable - I create the Produced Work, and you 
reverse-engineer it.

4) A Produced Work is not a Derivative Database, and so does not fall 
under the ODbL. The ODbL is designed to allow you to license Produced 
Works however you choose.

5) Therefore, I submit, the reverse engineering clause cannot be made 
enforceable by copyright permission, in the manner of e.g. the GPLv3, 
because the ODbL does not make claims on the copyright in the Produced 
Work. This is one reason why the ODbL must be a contract, in all 
jurisdictions, not just those with no database right. The person 
creating the work is contractually obliged by the reverse-engineering 
clause of the ODbL to respect this restriction, and to pass the 
restriction to anyone to whom they pass the Produced Work.

6) A no-reverse-engineering stipulation counts as a "further 
restriction" (GPL) or imposed term (CC-BY-SA) on the use of the work, 
which restricts a right.

7) Specifically, the right so restricted is the right to make derivative 
works of a certain type - databases of map data. The right to make 
derivative works is clearly a right that these licences wish to preserve.

8) Therefore, it is not possible to have a reverse-engineering clause 
for Produced Works, and also for it to be possible to create Produced 
Works that one can license under any licence with a "no additional 
terms" clause, including share-alike licences. It's one or the other.


So what can be done? I agree that reverse engineering is a risk. Life is 
not perfect. But still, my suggestion is that we should abandon the idea 
of trying to prevent reverse engineering, for the following reasons:

a) GPL and CC-BY-SA compatibility of produced works is more important.

b) If people are reverse-engineering our stuff, either they need a 
massive, sustained, continuous Mechanical Turk effort, or their map will 
be out of date anyway.


Gerv