I just hope the keys are not his home/office keys. Please do not secure the access to your digital life with an U2F token and break the security of your real life by putting a picture of your keys in the open...
Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
21–30 of 94 posts
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#22The programmer link is not working.
> The page isn't redirecting properly
http://www.digikey.com/product-detail/en/silicon-labs/DEBUGA...
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#23Earlier quoted context omitted.
No it is purely a hardware peripheral that just has configuration options. http://www.atmel.com/Images/Atmel-8923S-CryptoAuth-ATECC508A...
What does this do that can't be done with a generic AVR chip? If you set the correct lock flags the memory and firmware can't be read or changed without a complete erase: http://electronics.stackexchange.com/questions/53282/protect...
The crypto involved in U2F is extremely hard to do in an AVR. There are issues with sources of randomness (I'm currently playing with implementing entropy via Watchdog Timer jitter on the ATTiny85, which appears suitably random but is slow), and the capabilities of the devices themselves to produce output at reasonable speeds.
A slower Cortex M0 might not be sufficient to get decent speeds, but I suspect an M3, something like an AT91 could do the job.
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#24I'm curious about the following statement in the README:
> The token is durable enough to survive on a key chain for years, even after going through the wash.
On the other hand, the token is shown as "naked electronics", without a husk.
Is that really sufficient for such a device? Does it really withstand (mineral) water, mechanical stress (key chain), let alone the combination of both (washing)?
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#25I'm curious about the following statement in the README: > The token is durable enough to survive on a key chain for years, even after going through the wash. On the other hand, the token is shown as "naked electronics", without a husk. Is that really sufficient for such a device? Does it really withstand (mineral) water, mechanical stress (key chain), let alone the combination of both (washing)?
Looks like it would do fine to me. You would want to clean it with alcohol if you ran it through the wash, to avoid corrosion, but otherwise it would be fine.
I think it would be tough to break the board, so mechanically the worry would be bending some pins such that they shorted.
I have no idea what the ESD sensitivity of the parts is, but if it's something your going to walk around with in your pocket, that's something to think about. I'd probably use some heatshrink tubing on it.
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#26I didn't know github also supports 3d models with visualization
For those confused, see https://github.com/conorpp/u2f-zero/commit/dd71758a
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#27My barrier to entry with a lot of DIY hardware projects was an incorrect assumption that it was difficult/expensive to get PCBs made. Looking into this, I found the blog of the guy running this project and he had some experience with various cheap PCB vendors, with stencils going as low as $18. [1] [1]: https://conorpp.com/2016/03/13/my-experience-with-dirtypcbsc...
In addition to the vendors you mention via that link, OSH Park[1] is great option for hobbyists (or very small-volume production). This is the same source listed in OP. It's a board pooling group that puts many small-run orders on the same panel to economize on setup costs. OSH Park uses high-quality US manufacturers to produce the boards (with tight tolerances, silkscreen, soldermask, gold-flashed pads, etc.) I beli…
One thing I noticed is that some of my friends that have been designing PCBs have been dismissing options like OSHpark for a long time. Apparently they still believe that it's not possible to create good quality PCBs with that pricetag. Even after I showed them some of my PCBs they still insist that I got lucky and tolerances will be too high to be useful ...
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#28I'm curious about the following statement in the README: > The token is durable enough to survive on a key chain for years, even after going through the wash. On the other hand, the token is shown as "naked electronics", without a husk. Is that really sufficient for such a device? Does it really withstand (mineral) water, mechanical stress (key chain), let alone the combination of both (washing)?
It would absolutely not survive for very long like this (naked PCB on a key-chain). Mechanical damage from the actual keys on the same chain is what will kill it before water, sweat, washing liquid, pocket lint or ESD do.
First things to fail will be ceramic capacitors torn/cracked and leads of SSOP-20 package bent/shorted.
That said, it is trivial to protect the board from all of above - just wrap it (except USB connector) with insulating tape or better yet, cover with silicone putty, or similar.
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#29I just hope the keys are not his home/office keys. Please do not secure the access to your digital life with an U2F token and break the security of your real life by putting a picture of your keys in the open...
Those are pretty low security keys, just picking the lock might be easier than going to trouble of making them from the picture..
Re: Show HN: A secure, open source U2F token you can make with $4.5 worth of parts
#30My barrier to entry with a lot of DIY hardware projects was an incorrect assumption that it was difficult/expensive to get PCBs made. Looking into this, I found the blog of the guy running this project and he had some experience with various cheap PCB vendors, with stencils going as low as $18. [1] [1]: https://conorpp.com/2016/03/13/my-experience-with-dirtypcbsc...
A lot of amateur radio HF range projects use what is known as the "manhattan style" construction where, a copper clad board is used as a ground plane, so to speak and then tiny round pads are glued to it, which act as islands. The pads can be made using paper punch of appropriate grade. I have used cheap punch used for cutting paper and have made pads in the past. The parts are then soldered directly to these island pads.
Not sure if these can be applied to digital circuits, perhaps not very easily, since a lot of components are SMD these days, at least in the high speed digital domain.