cobratbq

7 ms·

1.
by cobratbq 2y ago
The comment is meant to separate the hardware from the protections possible in software. TKey provides a unique secret per device, that transforms into a unique secret per (device + program-binary + user-secret). So, protection against swap
2.
by cobratbq 2y ago
You're right. I misremembered; read up on a lot of things in last months. Doesn't really matter, because we're discussing a protocol anyways.
3.
by cobratbq 2y ago
Yeah, sorry, I realized that later. I forgot I posted the comment already.
4.
by cobratbq 2y ago
> No protocol exists completely separate from its implementation. That's a fair point. I am well aware of this.
5.
by cobratbq 2y ago
I'd love to respond to this, but your comment "... that explicitly provides no security guarantees when someone has physical access to it, .." is too abstract for me. I'll make a few guesses. - Is the device hackable? AF
6.
by cobratbq 2y ago
I'm not sure if we're talking about the same things. I am not confident that I understand your comment well enough to confirm/reject, so I'm going to clarify for that reason. > I understand it that the above quoted te
7.
by cobratbq 2y ago
> I don't know much about the TKey, but it looks like they have some kind of remote attestation protocol available? ( https://github.com/tillitis/tkey-verification/tree/main/cmd/ ...). That&#
8.
by cobratbq 2y ago
That's fine. It is indeed possible to perform a check for genuine hardware. (I'm not sure it qualifies as "attestation".) It does not protect you from malicious program-binaries and swapped devices.
9.
by cobratbq 2y ago
> I think you're over-describing your use case, to the point that it's unclear what you're really saying. I read your "Introduction" section several times, and I don't understand if you're just saying &
10.
by cobratbq 2y ago
I will have a look. I checked quickly already, so if I understand the notation, I also leave out the last transaction. (2 messages vs 3 messages) Presumably because the authentication is one-sided. Will investigate further.
11.
by cobratbq 2y ago
You're right. I wanted to abstract away from specific hardware and express that in the requirements. I definitely failed at that. See other comments for specifics and details on the device.
12.
by cobratbq 2y ago
Yeah, thanks for reminding me. That is a nice suggestion.
13.
by cobratbq 2y ago
You're right, mostly. I am not sure if TKey is officially considered an enclave. See more details here: < https://news.ycombinator.com/item?id=39834820 >
14.
by cobratbq 2y ago
I understand the "roll-your-own-crypto" comment. Note that I am taking the perspective of the protocol here, right? So, sure, vulnerabilities in the program are definitely a possibility. (See also other comments explaining more de
15.
by cobratbq 2y ago
To check: did you realize that you plug this device in your USB port, then send a program to it, then start using the device with that program loaded? (This is at run-time, every time, right?) Because the secret is generated for this specif
16.
by cobratbq 2y ago
Thanks, much appreciated. I'm not claiming to know everything, far from it. However, given this simple but interesting device (see other comments for details) I prefer to keep things simple. This is my attempt at simple-but-correct. :-
17.
by cobratbq 2y ago
I get that Verifpal is not perfect, doesn't do everything. I have considered switching. However, a significant part of proving the mechanism is having correct definitions for all of the needed primitives. If Verifpal tackles the right,
18.
by cobratbq 2y ago
See also my other comments. The device is tillitis TKey. There is a True RNG (source of entropy) but not recommended, i.e. not cryptographically-secure. However, together with Blake2s (in firmware) or another hash-function, you can at least
19.
by cobratbq 2y ago
Thanks for the input. See < https://news.ycombinator.com/item?id=39834820 > for more details. The device is the TKey, so essentially only 32-byte secret value that is determined at program-load-time. (See more details i
20.
by cobratbq 2y ago
Thanks for the feedback. See also comment https://news.ycombinator.com/item?id=39834820 Note that this device is general purpose security device with no persistence. So the requirements were really specific for that reason.
21.
by cobratbq 2y ago
The device I have in mind, primarily, is tillitis' TKey. The TKey does not have persistence, and offers a 32-byte secret value that is deterministically unpredictable (Blake2s) depending on hardware + program-binary + user-supplied-sec
22.
by cobratbq 2y ago
The device I primarily had in mind is tillitis' TKey. Essentially a general purpose (slow) processing unit. The secret is 32-bytes long and given no storage, that's essentially all you work with. However, the secret is dependent o
23.
by cobratbq 7y ago
1. Be thorough. Be sure you fully understand the issue, instead of jumping to conclusions. 2. Keep asking 'why'. Make sure you understand what the problem (or rather the requested feature) is, instead of being able to parrot wha
24.
Ecuador Detains a Friend of Assange. Critics Say It’s Guilt by Association(nytimes.com)
1 points by cobratbq 7y ago|0 comments
25.
by cobratbq 7y ago
Updates on his situation (more recent on top): - 2019-04-18: Ola Bini's statement, from arbitrary detention, statement discussed in an article. [10] - 2019-04-16: Ola's parents are able to visit him in prison, Ola has been getting
26.
Ola Bini: privacy defender, free software developer still in detention in Ecuado
59 points by cobratbq 7y ago|6 comments