Cynic posted
>On Fri, 9 May 2008 18:09:24 -0700 (PDT), Jethro
> wrote:
>
>>Does anyone know of any software which will allow a person to create a
>>hash of a file (say a text document) with a specific key. The idea
>>being that the hash can be published with the document, but the
>>original author can prove it was he who signed it (implying it was he
>>who wrote it).
>
>PGP - download for free.
>
>>Would such a system be admissable in a UK court as proof of prior
>>authorship ?
>
>Yes, I should think that it would be admissable, though it may be
>necessary to hire a suitable expert witness to explain to the court
>how it works and how effective it is.
>
>All it proves of course is that you had the document in your
>possession at some time. It does not prove that you are the author of
>the document. Anyone could take the document, remove your digital
>signature, append their own and republish it.
Jethro could try to use the fact of his prior publication to indicate
his authorship, as is done in patent law and science research. But that
wouldn't prove that he hadn't previously stolen the document from
someone else before that person had published it (as also happens in
research!).
What Jethro might do is publish *only* the hash of his document (perhaps
with a brief description of its contents) not the text itself. If he
later wants to disclose the document to someone, he can prove that it
was in his possession at the time the hash was published. No-one else
will be able to do that, because no-one else will hold a copy of the
plaintext.
--
Les Invalides |