Guns and computers

[Aguila Blanca]

Passing along a question from the M1911.org forum:

If any of you are at all into 1911s, you probably know that there are a couple of versions of the blueprints for the M1911A1 pistol available on-line, and there have also been at least two companies offering printed versions of the complete blueprints for sale. BUT ... as far as I know, there have never been any blueprints for the smaller Officers ACP version of the 1911.

Some of the guys on the M1911.org forum have been working on producing a set of blueprints for the Officers ACP. The original plan was to offer the full set in a book format, reduced to fit on either 8-1/2 x 14 paper or 11 x 17 paper. But, these days it seems that everyone wants to download stuff, and be able to view it on their cell phone. The problem with selling a digital copy, of course, is that the owner sells one copy, and suddenly 25 million people have copies of that copy.

I've been asked about ways to prevent this from happening, and I don't have a clue. If we have any Acrobat gurus here, can you point me in the right direction?


As an aside, if you were a do-it-yourselfer looking for a set of plans, would you prefer the 8-1/2 x 14 format of the 11 x 17 format?

I think the important question is the one about copy protecting a digital file. Less important, but still of interest at least to me -- if you were going to buy a dead trees version, would you prefer 8-1/2 x 14 or 11 x 17?

[L2R]

Protecting digital files has severe limits. You can convert CAD models and drawings to PDF, tiff or other types of files but that only keeps others from making changes to the original file. But once you give out a drawing with dimensions, the cat is out of the bag and that makes it much easier to reverse engineer something or share with anyone.

Bigger is always better but if the parts are simple, it isn't necessary.
11 x 17 allows for bigger views, allows for multiple views or allows for better detail of complex parts.

And it's not necessarily either or.
11 x 17 can also be folded twice so it fits into a 8 1/2 x 11 folder and the title block is still visible as you thumb through the pages. Again, 11 x 17 when needed.

[FrankenMauser]

Copy protection is difficult, aside from high level encryption.
The best way to approach this, if trying to protect the work (and potentially make a profit) is to follow the path of companies that sell plans for home-built aircraft.

They know that copies will be made. They know that people will try to resell their $300 set of plans. They know that they're going to lose money.

So, they do two things:
1. Anything publicly release has intentional 'mistakes' in the prints/plans (such as "sample" drawings shown on websites or in books). Some are big, like changing all of the dimensions for the left wing, so that anyone building from the 'public' copy is going to build one wing two feet too short and with three ribs missing. Some 'mistakes' are small, but numerous: Like specifying the length of every stiffener some random amount too short or too long - but within 1/2", or so.
2. EVERY copy of the plans gets a unique serial number, plus hidden identifying data. This way, if a copy of the plans shows up online somewhere, they can track down the original purchaser and pursue legal action. You cannot, of course, reveal what the data is, or how it's being hidden.

Just one example of many ways used to hide identifying data in aircraft plans, is using simple "revision numbers" or characters claimed to be for 'internal use only' in something like a drawing reference key on each page:

Spar cross section:    Dwg-345-678-A(IV)
Rib forming buck:      Dwg-345-679-AA(III)
Rib doubler:           Dwg-345-983-CG(IX)
...Etc...

...Where the Roman Numerals represent the serial number, or 'hidden'/second serial number.

There's a company in Canada that goes so far as to assign internal serial numbers, along with the visible serial numbers. Somehow, they include the hexadecimal check sum of the drawing number, visible serial number, and internal (hidden) serial number in each drawing. It makes every page unique, identifiable, and traceable; even though identifying the check sum is not easy, since it's different on every page.
And it means that any page without a correct check sum has been adulterated or copied and modified (both being copyright issues).

[T. O'Heir]

"...Copy protection is difficult..." St. Bill's minions have been doing it for eons with MS products. It's not difficult, but it is pricey. MS Office, for example, can only be installed on one machine with the CD code that comes with it. In the software someplace, there's a bunch of lines of code that look at the hardware on the machine takes a 'snap shot of it' and disallows any changes. Means that if you buy a new machine, you have to spend time on the phone with one of St. Bill's minions.
The best option for a guy selling plans is to sell a CD hard copy and not distribute the plans on-line.
Mind you, the difference between an Officers Model and a regular 1911A1 is the length on the slide and barrel. .75" difference in length. Frame's the same.

[Onward Allusion]

Digital Rights Management is hard to enforce. Sure, with PDF's one can password protect , prevent printing, & prevent modifications. DRM can not only encrypt files but also set them to expire, to only be opened by certain individuals (w/o login btw), prevent printing, screen capture...the list goes on. The problem is that once it is on a screen, what will stop someone from capturing it with a hi rez digital camera and converting it back to blueprint format? Also, most commercial stuff can be cracked. Serious...

DRM provides some protection, however, there are reasons why copyrights are a bear to enforce. This is the reason why authorities go after the distributors and not the peer to peer users. Also, once something is cracked and dumped into the dark web, I highly doubt any individual or authority can put the horses back into the corral.

Now, with all that said - we're talking blueprints for a gun not plans for cold fusion - most enthusiasts won't go thru that kind of trouble to save a few bucks.

[Aguila Blanca]

Originally Posted by T. O'Heir

Mind you, the difference between an Officers Model and a regular 1911A1 is the length on the slide and barrel. .75" difference in length. Frame's the same.

Actually, the frame is different in a number of ways, not just the most obvious (the shorter grip holds one less round).

[Scorch]

the difference between an Officers Model and a regular 1911A1 is the length on the slide and barrel.

Nope, nope, nope. Yes, the slide is different, but that's not the only difference. Yes, the barrel is shorter, but that's not the only difference. And the frame is different in several ways (shorter dust cover, shorter grip, different spacing of grip screws, etc).

Even if you were thinking about the Commander model, there are differences besides barrel length and slide length.

[MarkCO]

Actually, copy protection is easier on a digital platform than on a printed on. I have taken high res images of paper and relatively easily convert them to correct digital, even CAD files with a few clicks.

One has to decide the path that is best for their product...software or hardware. Software can be gotten around easier than hardware. Most of the secure files I use for programs have an encryption key on a USB. If the USB is not installed, no worky. I also get protected files on cases that use Adobe encryption. They can't be copied or converted and I have to enter a password to open them...if I block cookies, no worky. Not sure how hard that is to get around as I have never tried, but my software guys tell me it is pretty good.

If I never have to buy another hard copy, fine with me.