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Show HN: Kryptonite – a new home for your SSH private key

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Re: Show HN: Kryptonite – a new home for your SSH private key

#72

Hey HN! We've built a way to generate an SSH key on your phone and use it from your computer such that the private key never leaves the phone. We were inspired by the threat model of USB HSMs like the Yubikey and set out to build a free, public source, and easier to use BYOD alternative. Looking forward to your questions!

license :(

this exact thing is on my devs teams backlog. if you figure out a good license it would be AMAZING for us.

Re: Show HN: Kryptonite – a new home for your SSH private key

#73
post #57
post #54

Earlier quoted context omitted.

I will likely end up using this in personal capacity, and would also appreciate if the UX of using Google Authenticator were more similar to this, rather than requiring me to screenscrape my phone with my eyeball and then type information into another device (or, more painfully, another window on the same phone). The easiest way to do that probably results in a callback to Big Daddy G every time I access anything sen…

> The easiest way to do that probably results in a callback to Big Daddy G every time I access anything sensitive and I'm cool with that. Why?!

Because they have one of the most competent security teams in the world and enough money to mount legal defenses against governmental adversaries.

For many many threat models this pairing is a more competent defense than just about any thing a single person could come up with.

Re: Show HN: Kryptonite – a new home for your SSH private key

#74
post #65

The faq says there is intentionally no way to extract the private key due to security. But this means I need a second account in case my phone gets lost - the key of which I once again need to secure. How is that more secure than letting me backup the private key in the first place?

The current version is designed for hosted services like GitHub, redeployable infrastructure, and servers to which multiple people have access. We totally understand your use case and are actively working on implementing transferring a key to another device or printing out a paper backup.

Re: Show HN: Kryptonite – a new home for your SSH private key

#75
post #46
post #33

It sounds very hipster and all, but how is a phone more trustworthy than a Linux PC? Cool, we don't need to trust a PC, now we have to trust a phone and pretend that malware for smartphones don't exist at all. Hardware USB token looks much better as its attack surface is so much smaller than iOS/Android.

* Every application on the phone is sandboxed. * The disk is encrypted by default, and the OS is aggressive about keeping it encrypted ; a booted-up computer is almost always decrypted. * The language runtimes on the phone are hardened. * The phone's kernel, in addition to being more important attack surface than the Linux kernel (because of the jailbreak market, among other things), is auto-updated. * The phone's us…

>>> The phone's kernel, in addition to being more important attack surface than the Linux kernel (because of the jailbreak market, among other things), is auto-updated.

Most android phones are not updatable at all since manufacturers don't publish any update.

That, alone, should be enough to put phones among the most vulnerable devices on the planet.

Re: Show HN: Kryptonite – a new home for your SSH private key

#76

Earlier quoted context omitted.

The attack surface may seem smaller for USB tokens, but storing the pin for say a Yubikey allows malware to use the key without restriction. Also, these USB devices don't have a UI, so you never know what you are actually approving, i.e. which username or server you are logging into.

Erm, not true - changing the Yubikey setting to require a touch for key use (S/C/E) is trivial. Malware can't use it without restriction if it requires you to physically touch it every time you want to approve use.

So, capture the auth and use it for the malware, show the user some failure and allow their retry to pass. Stupid dodgy Yubikey fails half the time.

Re: Show HN: Kryptonite – a new home for your SSH private key

#77
How does this handle SSH session re-keying, does that need further authentication from the device? openssh does this pretty infrequently, I can't immediately remember if that needs participation with the asymmetric key or not.

ED: Seems it's just as if you re-did the cipher negotiation, so no asymmetric interaction.

Re: Show HN: Kryptonite – a new home for your SSH private key

#78
Seems pretty cool - I've just installed it and having a play with it. A couple of questions:

1. So I have to update all my servers to use my Kryptonite SSH key from the current Private Keys that I have?

2. This solution still doesn't allow me to SSH into my servers from another machine that doesn't have my private keys on it (such as a colleague's Mac), does it?

Re: Show HN: Kryptonite – a new home for your SSH private key

#79
post #64
post #61

Earlier quoted context omitted.

I thought the big fundamental vulnerability was that many baseband processors operating the phone's radio has dma to the memory of the entire device.

This is a myth.

I don't understand, I'm going off of information such as this [1][2]. Do you mean that shared memory vulnerabilities described in [2] has since been closed? Or maybe I'm being imprecise with terming it "dma" access?

[1] http://boingboing.net/2016/07/20/baseband-vulnerability-coul...

[2] https://www.usenix.org/system/files/conference/woot12/woot12...

Re: Show HN: Kryptonite – a new home for your SSH private key

#80
post #54
post #47

I haven't reviewed the implementation, but this is a really good idea. I want one.

I will likely end up using this in personal capacity, and would also appreciate if the UX of using Google Authenticator were more similar to this, rather than requiring me to screenscrape my phone with my eyeball and then type information into another device (or, more painfully, another window on the same phone). The easiest way to do that probably results in a callback to Big Daddy G every time I access anything sen…

The Google App can do this on iOS, rather than Google Authenticator, for some reason.

https://support.google.com/accounts/answer/6361026?hl=en

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