On Mon, 11 Sep 1995 owner-cypherpunks@toad.com wrote:

Hal Finney wrote:

...

I'm not sure how to do it for software, but for novels it should be easy to fingerprint. Every couple of pages the author writes a sentence twice in different forms. This would not take a great deal of extra effort on the part of the author.

Perhaps. Some authors might be offended by the idea that using a different form of a sentence doesn't affect the work.

Examples of "text tracking" in documents where language specificity is important (legal, scientific) are typically marked with changes in the justification scheme, i.e. the number of spaces to the right, number of lines to a page, number of pages total, etc. etc. Clearly it is much more difficult to apply in digital schemes, but consider that in order to modify the scheme to avoid traceback to the distributer, one of two conditions must exist. 1> The distributer must be close to the initial release point. (If not, then all documents ABOVE the distributer in the chain will be text tracked, and all the documents BELOW the distributer will not. Clearly this will brand the distributer). 2> The distributer must be entirely outside the 'legal' distribution scheme. Remember also that uniform modification of text tracking methods is itself identifying unless several 'illegal' distributers are using the same sanitizing method. The same way you can get surgery to have fingerprints removed, but the resulting scars make you all the more identifiable.