Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror

Comment: Re:Weird article (Score 1) 165

by userw014 (#48621125) Attached to: Army To Launch Spy Blimp Over Maryland
Definitely a weird article. If you ignore the hyperbole, all you get is a military boondoggle. The idea that it's part of some NSA spying operation falls apart in the face of the Raytheon promotional material - "double digits of swarming boats" and "hundreds of cars" in the Baltimore area sounds woefully insufficient, either for tracking suspected cruise missile delivery systems or giving the NSA anything more useful than what they have.
I suppose it might be practical for protecting Marquette, MI from an invasion from Canada.

Comment: Re:Move to a gated community (Score 1) 589

by userw014 (#48604915) Attached to: Waze Causing Anger Among LA Residents
If the tolls were used to offset another public good (public schools being the only other one that's nearly as expensive), it might work to encourage either people living in-town, or some businesses leaving town. Of course, that would only work if schools and the toll roads were under the same authority. (FYI, I live in Ann Arbor, Michigan where while we might complain about traffic and parking, we don't have anything like LA's situation. But being part of Michigan, we probably have the worst roads in the nation and a GOP/Tea Party dominated state government that's so tax-phobic that it's even more dysfunctional than the US House of Representatives.)

Comment: Not quite a proof-of-concept (Score 1) 194

by userw014 (#48533799) Attached to: Trains May Soon Come Equipped With Debris-Zapping Lasers

The video shows some kind of wide laser projector about a centimeter or so above a test-rig, with sparks flaring off, and the rail moving at a (relatively) slow rate - perhaps one or two Kph.

If the sparks were only burnt excess "leaf material", that isn't a problem - but if it's rust or steel fragments burning up, that's material coming off of the rails - in effect, wear.

If this is intended to be used continuously while the train is in motion in order to keep the rails clear of debris, how much energy can be delivered to a leaf from a fixed projector moving at 50Kph? If this does deliver enough power to cause the leave to disappear in a puff-of-smoke, isn't there a chance of heating the surface of the rail enough for the carbon ashes pressed into the rail by the subsequent advance of the train to chemically react with the rail?

This might be ok for single layers of leaves - but how long does it take for multiple layers of leaves to build up on a rail?

If the huge amount of leaves in the video is characteristic of the problem they want to solve, won't the wind from the passage of any train moving at speed just redistribute more leaves on the rails behind it?

Comment: Re:Infrared Bandwidth? (Score 1) 216

by userw014 (#48503403) Attached to: How the Rollout of 5G Will Change Everything

I predate MIMO, so I had to take a brief refresher in what it is - and if I understand correctly what I read of MIMO (and what I read was correct - two important provisos!), MIMO seems to depend on using digital signal processing to be able to match the emit and receive channels, but it is using a physical separation (on the WiFi access-point side) of a few centimeters between antenna. I can see where you might find that kind of separation in laptops or even tablets, but not necessarily in a cell phone or an Internet-of-Things tiny appliance (like a light-bulb.) I couldn't tell how stateful the DSP part would have to be, or how long it would take to optimize for a particular set of signal paths. I also couldn't tell how well MIMO works out in a mix of MIMO clients and non-MIMO clients (like my IoT light-bulb). Can anyone offer any guidance?

QAM strikes me as (somewhat) incompatible with MIMO because using phase-shifted channels (QAM) (carrying different data) would be akin to space-shifted channels (MIMO) when the wavelengths and the distance between the antenna are similar - and the distance (and phase) between the MIMO antenna depend on the orientation between the sender and receiver of MIMO. But maybe that's just more DSPing?

Comment: Infrared Bandwidth? (Score 1) 216

by userw014 (#48498677) Attached to: How the Rollout of 5G Will Change Everything

800bps (call it 1600Ghz, using Shannon) is in the Far Infrared to (barely) mid infrared spectrum, and that's just base-band signaling (from a point-like source.) Doing any kind of modulation (to allow multiple channels for multiple simultaneous transmissions) is going to put that more firmly in the mid-infrared spectrum where things like the atmosphere appears to be opaque. I realize that this is a mass-media article, and depends on "... and then magic will happen" sort of science, but I don't see how this works (much less scales) without excessive speculation using ancient undergraduate digital communications classes too far.

But, to speculate WITH ancient undergraduate digital communications classes, I would think of things like this:

  • Multi-point (physical separation) of channels, with individual channels at more "modest" speeds. Something like 1000 locations per. simultaneous customer being served 800Gbps.
  • (As. per. above) very, very tiny cells, packed very, very, very, very closely together.
  • Very, very tiny ceramic antennae.
  • Extreme differences between upload and download speeds, like on the order of 10E6.
  • A hot-spot would literally be that.

Comment: Re:quick question (Score 1) 212

by userw014 (#48457935) Attached to: Launching 2015: a New Certificate Authority To Encrypt the Entire Web

It makes sense when you understand the trust model, but that takes some explaining and isn't as simple to "civilians" as "check to make sure that the site begins with 'https://' or look for the 'key' icon provided by your browser." (Asking them to verify the host/site part of the URL is the advanced part of the explanation.)

It's rather like teaching people how to cook by telling them "be careful of hot burners, pots, and pans", but that is what we in IT have been doing to "civilians".

Comment: Re:quick question (Score 1) 212

by userw014 (#48457861) Attached to: Launching 2015: a New Certificate Authority To Encrypt the Entire Web
It's the organizations that put strong controls over their staff use of desktop computers that do this when they generate an image. Those organizations that value micromanaging what their staff can do more than getting work done used to (and may still) block much of the internet, etc. and in that context of tightening everything down so much that the threads get stripped, managing the CA root list makes sense.

Comment: Re:Why do this (free, easy SSL certificates)? (Score 1) 212

by userw014 (#48420961) Attached to: Launching 2015: a New Certificate Authority To Encrypt the Entire Web
  • (A) Nearly worthless because a lot of the advice given out to "civilians" is that "https" can be trusted, "look for the lock", etc. More subtle advice (like check the URL, don't mistake "1" for "l" or "0" for "O", etc) are advanced techniques (at least for too many civilians.) Charging for SSL certificates - and the turnaround time it takes to issue them, install them, etc. meant that a certain class of quick-and-fast scams weren't practical. Cheap, fast, easy to install SSL certificates make this easier, thereby making the "https" indicator less valuable. (In short, use of "https" to "trust" a site is a gross mistake - but a mistake IT people have been advising civilians to do.)
  • (C) I'm not a security researcher, I know a little about running a CA. A faked up CA isn't going to help someone trying to figure out what an App is trying to send over a SSL session, unless they're somehow able to replace the certificate and key in the App. Of course, a web app isn't going to have a certificate and key - but a smartphone/tablet app might.
  • (i) On this, I think you're arguing that the CA system is even more broken than I am. I won't protest that.
  • (ii) I'm not going to cry - but if there's enough money involved, Congress will do something stupid.
  • (iii) I'm talking about "Extended Validation" certificates - which were an enhancement (via. another X.509 attribute) that suggested that the issuing CA did some due diligence (other than verifying that a credit card accepted a charge.) Whether the CA actually followed the guidelines is another matter. Is there a way for an outsider to audit this 'Extended Validation' for a particular Certificate? Without that, "Extended Validation" is just a way for CAs to charge more money.

Apps

Comment: Why do this (free, easy SSL certificates)? (Score 1) 212

by userw014 (#48413635) Attached to: Launching 2015: a New Certificate Authority To Encrypt the Entire Web

Why do this?
So that:

  • (1) App developers get used to designing and testing with https/SSL instead of gluing it in at the last minute AND GETTING IT WRONG
  • (2) to encourage encryption and privacy, and to make the use of https/SSL less likely to distinguish between valuable communication and noise

Why not do this?
Because it:

  • (A) makes the value of the https signifier on a URL / browser bar nearly worthless
  • (B) will encourage App developers to send even more information to poorly secured servers
  • (C) prevent researchers from determining what privacy-violating information an App is sending

What might happen because of this?
It will:

  • (i) break the already weak link between certificates and the organizations they represent.
  • (ii) kill the business model of the certificate authorities
  • (iii) result in another somewhat meaningless revision of the "verified" certificate

Overall, it might work out well - but I doubt that App developers are going to bother so the major good reason will be ignored. App developers will STILL get it wrong, and even if they do set up https, that'll just encourage them to pass even more sensitive information to poorly secured APIs.

Comment: Re:quick question (Score 5, Insightful) 212

by userw014 (#48413481) Attached to: Launching 2015: a New Certificate Authority To Encrypt the Entire Web

...

What might have been better is early on, have Web browsers accept self-signed SSL certs, and show some grey icon for that....

Web Browsers DID used to accept self-signed certificates (and certificates signed without a known CA - or cert-chain.) People just clicked through and accepted them willy-nilly. That was a poor security model. Although the existing security model of having a swamp of independent Root Certificate Authorities (per browser) is not too great either, but at some point you have to establish whom to trust - and for most of us, it's the browser vendor. (Some of us prune the Certificate Authority list and distribute the new list with software imaging technologies....)

1 Billion dollars of budget deficit = 1 Gramm-Rudman

Working...