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I am making an application that maybe needs to link a 3rd party library and needs to distribute an utility in its package. The library and the utility have a very permissive free license that authorizes me to link and distribute but how is it official? How can I be sure they do not change what they say on their website or in the license file and sue me in a future time? I am talking about those unknown little enterprises or single programmers.

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The license is the official authorization. –  chrisaycock May 2 '12 at 13:57
@chrisaycock How can I prove that I did not alter the license if they claim I did, after they changed by fraud the website and the package? Is there a public registration of that? –  P5music May 2 '12 at 14:02
If the software is hosted on a repository like GitHub or Bitbucket, then the embedded version control will have a previous copy of the license, along with the timestamps of when it was changed. –  chrisaycock May 2 '12 at 15:27
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3 Answers

I think you are being overly paranoid but you could try

  • have someone independent & reputable (e.g. your lawyer) witness you download the license + software (or have them do it on your behalf)
  • print the license
  • have the witness sign and date the print out

alternatively if you just want it documented as to when you downloaded it

  • print the license
  • post it to yourself via recorded delivery

There will always be some scenario where, with enough collusion by enough people, it is 'possible' for you and your 'accomplices' to have cheated them, for the same reason that you can never disprove a conspiracy theory. Stop worrying about it and relax.

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they could claim I have printed or delivered my altered copy of the license. the same for the witness idea more or less. –  P5music May 2 '12 at 18:32
they could also claim the whole world is involved in a massive conspiracy to defraud them and you are the ringleader, are you worried about this? –  jk. May 2 '12 at 19:40
@P5music They can claim all sorts of things, but if they can't make the claim stick in court then their claims don't mean a thing. –  Donal Fellows May 3 '12 at 9:36
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Rely on SHA1

Usually the license text is embedded in the downloaded artifact. This is normally subjected to a published SHA1 digest to ensure that what you downloaded is in fact what was uploaded by the author. If the author changes the license then they will have to release a new version with a different SHA1.

IANAL but it seems to me that if they just change the text on their website that cannot be made to apply retrospectively without some serious legal hassles.

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Lying under oath in court is perjury, and although IANAL my understanding is that the penalty for that can be pretty severe. Bringing suit against someone under false pretenses when you know that there's a pretty good chance that the other side will be able to prove not only that you're wrong, but that you're lying, would be unbelievably stupid.

That said, if you're really worried about it, you should a) consult with your own lawyer; and/or b) write your own library and utility, or use components that are distributed by someone you feel you can trust.

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Perjury tends to attract prison sentences. –  Donal Fellows May 3 '12 at 9:58
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