New 100W USB 3.0 Spec Can Charge Laptops • Hacker News Board

Re: New 100W USB 3.0 Spec Can Charge Laptops

#41

Post by cdcarter » Tue, Jul 24, 2012, 4:28 PM UTC

jonknee wrote: post #18

pieter wrote: post #16

I'd be careful with these; it means you can't plug in an untrusted power supply anymore. Just imagine one of these cables also acting as a USB keyboard, which brings up a new terminal, adds an SSH authorized key and closes the terminal window without you even seeing it.

How often are you currently plugging in untrusted power supplies? ThunderBolt can chain a lot of different device types but I don't think it's a huge attack vector to plug in untrusted monitors.

Personally, I'm borrowing someones magsafe at least once a week. A majority of students at my college use MBPs, so they are abundant.

Re: New 100W USB 3.0 Spec Can Charge Laptops

#42

Post by ConstantineXVI » Tue, Jul 24, 2012, 4:36 PM UTC

Tuna-Fish wrote: post #40

koenigdavidmj wrote: post #38

Earlier quoted context omitted.

And Thunderbolt is already dangerous, given that it's essentially just serialised PCI Express (so you've got a free view into RAM).

But you don't typically plug in random, untrusted TB cables -- you do typically plug in random, untrusted chargers.

Thunderbolt's the primary display connector on Macs as of 2011 (and some PCs); so not as common as chargers but not entirely outlandish.

Re: New 100W USB 3.0 Spec Can Charge Laptops

#43

Post by X-Istence » Tue, Jul 24, 2012, 4:41 PM UTC

koenigdavidmj wrote: post #38

pieter wrote: post #16

I'd be careful with these; it means you can't plug in an untrusted power supply anymore. Just imagine one of these cables also acting as a USB keyboard, which brings up a new terminal, adds an SSH authorized key and closes the terminal window without you even seeing it.

And Thunderbolt is already dangerous, given that it's essentially just serialised PCI Express (so you've got a free view into RAM).

There is security against that, you can limit access for thunderbolt devices to various parts of memory, same as you could with Firewire. Thunderbolt is not anymore insecure than Firewire for instance.

Re: New 100W USB 3.0 Spec Can Charge Laptops

#44

Post by [deleted] » Tue, Jul 24, 2012, 4:49 PM UTC

pieter wrote: post #16

I'd be careful with these; it means you can't plug in an untrusted power supply anymore. Just imagine one of these cables also acting as a USB keyboard, which brings up a new terminal, adds an SSH authorized key and closes the terminal window without you even seeing it.

[deleted]

Re: New 100W USB 3.0 Spec Can Charge Laptops

#45

Post by tjoff » Tue, Jul 24, 2012, 5:28 PM UTC

X-Istence wrote: post #43

koenigdavidmj wrote: post #38

Earlier quoted context omitted.

And Thunderbolt is already dangerous, given that it's essentially just serialised PCI Express (so you've got a free view into RAM).

There is security against that, you can limit access for thunderbolt devices to various parts of memory, same as you could with Firewire. Thunderbolt is not anymore insecure than Firewire for instance.

Considering that firewire is a popular attack vector that isn't really comforting...

Re: New 100W USB 3.0 Spec Can Charge Laptops

#46

Post by j_baker » Tue, Jul 24, 2012, 5:54 PM UTC

I'm curious if USB could be turning into the next electrical socket. Imagine if everything you plugged into a wall outlet used USB. Not only would it probably be safer, but it would probably mean the end of country-specific electrical adapters. Outlets like this are already becoming popular: http://www.amazon.com/Newer-Technology-Power2U-Outlet-Chargi...

Re: New 100W USB 3.0 Spec Can Charge Laptops

#47

Post by ars » Tue, Jul 24, 2012, 6:13 PM UTC

j_baker wrote: post #46

I'm curious if USB could be turning into the next electrical socket. Imagine if everything you plugged into a wall outlet used USB. Not only would it probably be safer, but it would probably mean the end of country-specific electrical adapters. Outlets like this are already becoming popular: http://www.amazon.com/Newer-Technology-Power2U-Outlet-Chargi...

Probably not. The 5v ones can't deliver enough power to do much, and if you have 20v you might as well have 120v - you anyway need to convert the voltage to whatever you use internally, and with 120v the wires are 1/5 the size (thickness).

Re: New 100W USB 3.0 Spec Can Charge Laptops

#48

Post by ars » Tue, Jul 24, 2012, 6:18 PM UTC

joenathan wrote: post #21

bryanlarsen wrote: post #13

picture of the new cable: http://m.hexus.net/tech/news/peripherals/42705-new-usb-stand...

That is a picture of a standard USB 3.0 A to B cable. Ex. http://www.amazon.com/Micro-Connectors-Superspeed-Cable-Feet...

No it's not. Look at the plastic "tongue" in the middle of it - it was pierced and they put the power connectors inside it.

Re: New 100W USB 3.0 Spec Can Charge Laptops

#49

Post by Dylan16807 » Tue, Jul 24, 2012, 6:30 PM UTC

ars wrote: post #47

j_baker wrote: post #46

I'm curious if USB could be turning into the next electrical socket. Imagine if everything you plugged into a wall outlet used USB. Not only would it probably be safer, but it would probably mean the end of country-specific electrical adapters. Outlets like this are already becoming popular: http://www.amazon.com/Newer-Technology-Power2U-Outlet-Chargi...

Probably not. The 5v ones can't deliver enough power to do much, and if you have 20v you might as well have 120v - you anyway need to convert the voltage to whatever you use internally, and with 120v the wires are 1/5 the size (thickness).

I find that argument suspect when I look at all the laptops that run on 19 volts. Internal adapters are a lot messier for 120v. Most computing things love the 12 volt range, my screen uses 19 volts, a fancy light bulb is either LED and low voltage or CFL and gets no benefit from 120.

Higher voltage is better for distribution and for very high power loads (including heaters). But a lot of things like low voltage.

Re: New 100W USB 3.0 Spec Can Charge Laptops

#50

Post by ars » Tue, Jul 24, 2012, 6:46 PM UTC

Dylan16807 wrote: post #49

ars wrote: post #47

Earlier quoted context omitted.

Probably not. The 5v ones can't deliver enough power to do much, and if you have 20v you might as well have 120v - you anyway need to convert the voltage to whatever you use internally, and with 120v the wires are 1/5 the size (thickness).

I find that argument suspect when I look at all the laptops that run on 19 volts. Internal adapters are a lot messier for 120v. Most computing things love the 12 volt range, my screen uses 19 volts, a fancy light bulb is either LED and low voltage or CFL and gets no benefit from 120. Higher voltage is better for distribution and for very high power loads (including heaters). But a lot of things like low voltage.

> Internal adapters are a lot messier for 120v.

Why do you say that? Look at any USB charging plug - very simple inside. You only need "messy" electronics for high power or high (above 80%) efficiency.

Basically you would need 20v -> 5v vs 120v -> 5v - there isn't really a lot of difference. (There is some, but not enough to make changing everything worthwhile.)

Also, the double conversion isn't great (you would need a power supply in each plug), assuming typical 80% power supplies you would end up with end to end 64% efficiency.