Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Comment Re:One time pad (Score 1) 87 87

What you've described has been known for centuries as a "book cipher". Benedict Arnold used one during the American Revolutionary War to protect his treasonous communication with England.

Anyway, there's a really fun way to beat this kind of encryption today. If Mallory can get Alice or Bob to send a copy of BLACK_SQUARE.BMP, it's literally game over. Imagine XORing your key against a bunch of binary zeros. The result is a big patch of the cleartext version of the data that is your key. Google will find that faster than you can.

I did this to a friend who had the same idea in a "you'll never guess my encryption" challenge. After getting him to download a copy of BLACK.GIF, I stared at the intercepted results for many seconds longer than I should have. It output a repeating string of something like SLASHDOTTODHSALS, so I said that's your key. He was arguing because his key was SLASHDOT, and his "algorithm" was to invert the letters of the key word and append a copy to the end of the key. My mind boggled because I was expecting encryption, not immediate success at recovering his key and data.

Now, let's say you're smart enough to avoid encrypting BLACK_SQUARE.BMP. I can still achieve most of the same results by predicting that your data stream will contain "Host:", "Content-Type:", "Accept: text/plain", "User-Agent:", "HTML", "BODY", and other such 'cribs' (I was all set up to apply this logic to the intercepted message from my friend mentioned above.) By matching fragments of my guesses with your message, I can look to see if I recover legible text. It only takes a surprisingly small amount of recovered text to be able to identify the source.

Comment Re:"I was spying on you from 200 feet, not 60!" (Score 1) 492 492

At 200 feet, a wide angle GoPro picture of somebody can't even identify their face, even at maximum resolution when you zoom in on the picture all you can.

Even at 60 feet, you'll have a hard time identifying somebody.

To really spy on somebody, especially if you want to be a peeping tom, you'll have to come in close. Ten feet, perhaps?

Comment Re:Really? (Score 1) 492 492

is that shooting vertically, at a drone above you, limits the maximum range of the shot.

Of course it does.

However, by how much? That's pretty easy to estimate. If we can ignore air resistance, if we shoot something upwards and it travels 200 feet ... sqrt(2 * g * 200 feet) is 113 feet per second. The object will have lost 113 fps due to the gain in altitude.

Now, of course we can't ignore the air resistance, but we can't ignore it when shooting horizontally either, and the 113 fps slowing simply due to the altitude gain is still accurate.

How does that compare to the speed of a shotgun out of the gun? From what I can find, that's usually around 1000-1300 fps, so it's only 1/10th of the shotgun blast's initial speed.

Based on that ... I would expect that shooting straight up at something 200 feet up vs something 200 feet horizontally would reduce your range by around 10% at most.

Comment Re:Really? (Score 1) 492 492

the drone pilot came storming over to the owners property and menaced the owner.

And how do you/they know that? Oh yeah, the owner told them.

The previous article had *nothing* from the point of view of the pilot, all you heard from was the oh so reasonable owner -- how he carefully used the safest shot, how it was hovering over his daughter, how it wasn't the first incident, how his careful display of force is what kept the belligerent pilot and his crew at bay, how he doesn't dislike "drones" -- he thinks they're fine and dandy, etc. Personally, it sounds like he was setting himself up to be the "reasonable man" and it's not clear how much of that was actually true.

Ultimately, if we can't trust the telemetry to be unmodified ... we can't trust the statements of the homeowner either.

In any event, the police were there and spoke to everybody involved, and they only arrested one person ...

Comment Re:Really? (Score 1) 492 492

A quadcopter has four propellers, each usually with two or three plastic blades. And they're often quite fragile. If one pellet hits one blade and breaks it -- the quadcopter is coming down immediately. It will only take one, so the only remaining question is -- is if still moving fast enough to break the fragile blades?

Comment Re: Might want to reconsider paying the fine... (Score 1) 492 492

IMHO one rule that needs to be established ASAP is that all camera equipped flights need a permit with predetermined flight paths, a period for filing objections, and a steep fine for failing to get a permit in advance.

You do realize that the vast, vast majority of camera equipped models have a wide angle lens that can't even identify individuals at over 75 feet or so, right?

The vast, vast majority of these pictures are of landscapes, buildings, crowds of unrecognizable people, and when they come closer -- it's generally in a public area and the people who are recognizable are fully aware that the craft is there. To actually use it to be an effective peeping tom would require that you get in so close that the target could certainly hear it and could probably even knock it out of the sky with a broom.

In any event, the FAA isn't really concerned with the privacy angle of things -- to them, their concern is safety.

Comment Re:Might want to reconsider paying the fine... (Score 1) 492 492

What about the drones used by activists to fly over industrial operations breaking the law and get footage of it?

Alas, Texas has already weighed in on that question.

Texas' unmanned aerial photography law basically says that it's illegal to "conduct surveillance" of other people's property without their permission -- and then goes on to explicitly say that if you do it anyways, the photographs can *not* be used in court, and the property owner can sue you for several thousand dollars for taking the pictures, and more for disseminating them.

This incident is probably what lead to that -- they wanted to protect companies from having their crimes be detected with them.

So ... you'll have to use a manned aircraft for that.

Comment Re:Nope... (Score 1) 492 492

Pretty much comes down to the privacy vs. security issue in the back of everyone's mind.

In this case, it'll probably come down to 1) where exactly was the quadcopter, and 2) does somebody have the right to destroy somebody else's property if it ends up on their property.

And note that the answer to #2 is already well known ... the answer is NO. They can remove the item, and they can even bill the person for the trouble of moving it, but they cannot destroy or take it for themselves.

drones themselves are likely a peeping tom's wet dream

Maybe in dailymail fantasy land, where every quadcopter is flown by a peeping tom looking to hover outside a girl's window and watch her undress.

In the real world, their cameras usually have have wide angle lenses and a person would be to small to be recognizable if the quadcopter was more than 75 feet away from them. The vast majority of the operators are simply taking pictures of houses, landscapes, the sky, etc. If there are people in the picture, they're incidental or just "a crowd" unless he brings the quadcopter within 25 feet of them -- and there's nothing stealthy about a quadcopter at 25 feet.

Comment Re:Different approach (Score 1) 76 76

There is this piece of Cat 5 that isn't remotely hackable. Unless it's tapped, or if someone puts an inductor on it, or if they use TDR to estimate the length of the wire to figure out the distance between routers and discover where the Intrusion and Detection Systems are located.

Comment Re:Wow, end of an era. (Score 1) 152 152

He was saying that the SS10 could handle 512 MB in 1992, at time when the best PCs were maxed out at 32 MB or so.

The SS10 takes proprietary memory, and I know there was a firmware update that allowed it to use larger (32 MB, I think) sticks at some point. Ultimately, I don't think there was any way to put 512MB into a SS10 in 1992, even if the machine did eventually support it. I think 128 MB was more likely, though even that's very good for a desktop box back then.

As for 128MB simms in 1992, I have my doubts. This chart doesn't really try to list *everything* that was available, but even so -- it doesn't list 128 MB sticks until 1999. (It doesn't mention 64 MB sticks until 1999 as well, so clearly, it's missing some stuff.)

According to this, there were 64 MB SIMMs available in 1995 for a massive price -- $2600 each. (I didn't try to find the ad itself, however.)

Comment Re:Wow, end of an era. (Score 1) 152 152

I was asking about the Sparcstation 10, not a PC.

Wikipedia says "The SS10 can hold a maximum of 512 MB RAM in eight slots", so that means we need 64MB modules for it, and I'm not sure they were available yet in 1992.

I've got a SS20 in my garage, and it's got 208 MB of memory -- which wasn't too bad at all, "back in the day" anyways.

Comment Re:I was thinking of "high end" in terms of (Score 1) 152 152

what consumers had access to by walking into a retail computer dealership ... and saying "give me your best"

Of course, by that metric, Suns weren't available at all.

SCSI was somewhat rare in a PC in 1992, yes, but not that uncommon. (Anybody remember the Adaptec AHA-1542B? It came out in 1990.)

800x600 was more common, but 1024x768 was available. I don't recall if it was all interlaced or not, but I do recall how much that interlacing sucked!

Ethernet (or token ring, that was still somewhat common) was quite common in environments where it made sense. Not in a one computer home of course, but in a business, sure. How else were you going to get at the NetWare server?

And in the PC space, the higher-end you went, the less you were able to actually use the hardware for anything typical.

That's not true. A high end business class PC would run games just fine in 1992, for example. (As long as it had the right graphics, anyways.)

You might need to pick a different boot floppy, however. (Windows 95 certainly did improve things there!)

I'm not sure if this applied to the few SMP PCs available the time or not, however -- I got my first one a few years later, a Pentium Pro. That wasn't specialized -- it would run anything, though I imagine that many things would ignore the second cpu. (I ran Linux on it, which did use the second cpu.)

The UNIX platforms were standardized around SCSI, ethernet, big memory access, high-resolution graphics, and multiprocessing and presented an integrated environment in which a regular developer with a readily available compiler could take advantage of it all without particularly unusual or exotic (for that space) tactics.

I understand nostalgia, but ... no.

SCSI was the (somewhat) new hotness in 1992, yes, but other drive busses had been used in the past and were still used in 1992. The large SGI I administered a few years later had ESDI drives, for example. (But it also had SCSI, and the desktop SGIs we had were SCSI only.)

Ethernet was also the current favorite, but other networking protocols were in use at the time. I was working at IBM in 1992 and most of the company used token ring at the time -- that's what I had coming to my desk, where I had a PS/2 running OS/2.

As for "big memory", yes, that was always the norm for big computers, whatever the OS -- big computers had big resources available.

As for multiprocessors, remember, the Sparcstation 10 was Sun's first multi cpu desktop box. Multiprocessing was somewhat common in mainframes and minicomputers by them (whatever the OS), but it was rare on the desktop, even *nix desktops.

As for graphics ... most Unix platforms had no graphics at all then. Sun's desktop offerings did, and they did have decent graphics, but they weren't really better than high end PCs that were available at the time. (SGI went more after the desktop graphics than Sun did, but maybe Sun had some stronger offerings that I'm not aware of.)

As for "integrated environments", I think in 1992 Sun still shipped compilers stock with their OSes, but it was just a few years later that they became a very expensive licensed add-on. gcc was available, of course, but getting it installed was kind of a chore, and it was inferior to the Sun compilers in some ways. Alas, g77 wasn't available until a while later.

And really, the environment wasn't "integrated" like it is now. No IDEs, anyways -- your environment was X windows, and you got to use vi or emacs or whatever. Really, the programming environments on a PC were integrated before they were on Unix systems as far as I know.

Comment Re:Wow, end of an era. (Score 1) 152 152

A 32 bit cpu can address 4 GB directly, but that doesn't mean it has a 4 GB memory limit.

For example, in 1995 Intel added PAE to their 32 bit Pentium Pro cpus, allowing them to access more than 4 GB of memory.

Hell, my Apple IIe had 128KB of memory, in spite of the 8 bit cpu with the 16 bit address space only being able to access 64KB of memory, through similar tricks.

And yes, 4 GB is enough for most casual users today. 2 GB even works. But give it a few more years and 4 GB will become very restrictive even for somebody who doesn't do much on their computers.

Personally, I'm not going to make any claims that "X KB/MB/GB/PB/EB/etc. will be all you'll ever need in your lifetime" because it seems quite likely that whatever I pick ... it'll turn out to be wrong.

%DCL-MEM-BAD, bad memory VMS-F-PDGERS, pudding between the ears