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Comment by tptacek | Hacker News Reader

Because the parts you need to provide the functionality you want at the level of security Yubico is promising are expensive.

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Are there technical reasons that device (well, maybe not quite that blue-sky-ish, but the general idea) can't be your phone? You've already paid for it, people seem to think they're quite secure, etc. I don't get the whole desire to make hw tokens more computery so we can better use our computers while also already carrying another computer in our pockets.

This is a can of worms. Experts will tell you that iPhones are quite secure, and there is a lot of hardware security going into making them secure. It doesn't follow that any piece of hardware you build with L4 and a cheap ARM core will protect keys, such that losing sight of your token for a couple minutes won't mean you have to ditch the keys it stored.

Right, I mean a secure phone, so a recent iPhone with the enclave and the exurb and the whatnot. The U2F key I get - it's cheap, it's indestructible, I can buy a bunch and put them on my keychain and hide them under the couch and forget them in drawers filled with old SCSI terminators. But the phone already can do things like, say, authorize access to my google account by gmail app push notifications. Why not my ssh keys or all the other zany things people want to do with fancier USB tokens?

I think (I don't have the numbers and I might be wrong) that the price difference between a Yubico U2F key and the Yubico Y4 key that will also hold your SSH key is in large part down to the BOM cost of the NXP chip they're using as the on-board HSM.

Krypton does this:

https://krypt.co https://krypt.co/developers

It acts as a U2F token, but can also hold a private key for SSH authentication and/or git commit signing. On iOS, it can use the secure enclave.

You would then have to replace all the not-secure phones your users have, iOS market share is ~15%. It could work for company-internal things w/ work phones though. Phones generally get lost, broken and out of battery a lot though.

Why not just house the yubikey guts inside the phone enclosure then?

Separation of duties. You want the hsm to be unchanged in many years with minimal maintainance. While your phone is already being used for too many things which means it will need an upgrade frequently and you will have a harder time securing it.

Think of the hsm as just another key on your keychain. It has no ui other than a button,does not need charging and will remain in your pocket until needed. You don't want someone grabbing it off your hand while texting or making a call,that would mean they can access all your accounts.

The Yubikey Neo has a whopping 2 ICs on the board. The secure element is around $6 and the microcontroller is almost certainly cheaper than that.

http://www.hexview.com/~scl/neo/

https://www.avnet.com/shop/apac/products/nxp/a7005cghn1-t1ag...

I don't buy that argument. I have purchased Blu phones for under $50,yubikey nano cost me ~50. Plus,it gets even cheaper with mass production.

A cheap smartphone without radio,screen,large battery with a custom os and a usb connection would be an even cheaper phone. The only things a personal hsm would add might be nfc and hardware rng. I'm surprised yubikey hasn't gotten cheaper even with companies like google using it.

> I'm surprised yubikey hasn't gotten cheaper even with companies like google using it.

The cost is probably much cheaper, but there is no reason for them to lower prices when there isn't really major (popular) competition.

I think once Google releases their key for general sale, Yubi will be forced to drop prices to compete.

Google's key is, from what I understand, just a relabeled Feitian. You've been able to buy them for a long time.

Feitan are also way less reliable than Yubico. My Yubico keys have lived in my pocket on my keyring for six months, no problems. My feitan sat on a shelf, and its Bluetooth is now so unreliable I'm getting a second Yubico key for nfc.

That phone does not make the hardware security promises Yubico makes. You can't make a hardware security module with a cheap ARM core and nothing else.

True, but an ARM core and a ATECC608A ?

- FIPS compliant RNG and key generation

- Hardware based key protection

- Secure (encrypted) on chip key (ECC, AES, SHA HMAC) and data storage

- Guaranteed Unique 72-bit Serial Number

- Boot validation

If what you need is the management of 16 different NIST P-curve keys and nothing else, and you don't necessarily care if the whole package is secure against DPA, that part is a cheap way to get that.

But that's not what people on this thread are asking for; they want it to do all the crypto stuff they do normally, with all the keys secured in hardware.

I'm a little out of my depth on this stuff; I've done chipset work but my part of those projects always starts with the C code. Maybe you can accomplish what you want with a cheap crypto IC. I'm really just pushing back on the idea that because you can build a smartphone out of a cheap ARM core, you can also build an HSM out of one.

> If what you need is the management of 16 different NIST P-curve keys and nothing else

You can put AES keys in the slots and have the IC perform operations with them.

> and you don't necessarily care if the whole package is secure against DPA, that part is a cheap way to get that.

Go get the NDA datasheet.

> (HSM out of ARM core alone)

We agree here.

That's AES (right, of course; I assume arbitrary small blob of data, but these are the operations the IC can do itself without you having to drag the key out into the SRAM of your MCU) for GCM, and P-curve ECC. It's not SSH, right, or Signal protocol. It's just designed to drive TLS, and can do U2F.

Does the data sheet talk about hardware side channel mitigation?

Check out the Datasheet of the ATECC508A, it has been available without an NDA since Jan 2018.

http://ww1.microchip.com/downloads/en/DeviceDoc/20005927A.pd...

Would it not be possible to use hardware that can make similar security promises using the cost saved by not having the LCD and Battery?

USBArmory is around ~$100,I'm essentially talking about a mass produced user friendly version that cuts 40-60% of the cost due to mass production and slightly less extravagant hardware.

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