"Do you think this cannot possibly be secure? Great, prove it.
This secret contains the recovery key for a Bitcoin wallet. Crack it and take my money!"
Love it.
This secret contains the recovery key for a Bitcoin wallet. Crack it and take my money!"
Love it.
Attaching a challenge made a big difference, they'd spend 5 minutes trying to crack it and, in the process, realize it is actually sound (despite the simplicity).
FWIW, it's a simple composition of complex things. Still really cool, thanks for the idea!
(People are busy, attention is scarce, etc)
That being said, I think most security professionals (myself included!) aren't equipped to outright "crack" this kind of thing in just a few minutes, and most should know better than to think that their inability to do so implies soundness.
With that in mind, here are some things I noticed (none of which represent an immediate break!)
* You're using SHA-1 in your KDF. That's probably fine since PBKDF2 doesn't rely on the properties of SHA-1 that have been broken, but the Web Crypto API gives you better alternatives. You could switch it out for SHA2-256 here without any breakage to the rest of the scheme.
* I'm not a JS expert, but I _think_ your encryption page might allow a confused user to reuse an IV[2]. Normally this wouldn't happen because the user would refresh or reload and trigger the `init` on page load, but it would probably be better to generate the IV on demand rather than having it wait in an HTML attribute.
Again, very cool work! The fact that people can make these kinds of self-containing encrypted applications with Web APIs is a serious testament to how far the standards have progressed.
[1]: https://github.com/mprimi/portable-secret/blob/3b22d2b42baf8...
[2]: https://github.com/mprimi/portable-secret/blob/4de5e958fe6f8...
> most security professionals (myself included!) aren't equipped to outright "crack" this kind of thing in just a few minutes
When I say 'crack' in this context, I mean review the scheme and point out any obvious flaws, like you just did!
> SHA-1 -> SHA2-256
I should do this!
> reuse an IV
Indeed (there is a fine-print in the creator page that says "don't reuse across messages", but I should just regenerate proactively)
Thank you very much for the great comment!
(Now I gotta go wash my hands after typing this.)
It doesn’t necessarily prove that the encrypted key is valid, but it proves that the author put some money up on the chain at least. It could always be that the decrypted text doesn’t provide the key that fulfills the contract, but ultimately that isn’t a solvable problem. You can’t prove a claim about some encrypted text without someone having the ability to decrypt it.
Proving that an encrypted text has the private key is possible for some encryption schemes through zero knowledge proofs, but I guess not in this case in particular.
This secret image contains a Bitcoin wallet recovery key
If you can crack the secret, the funds are yours!
You can check the status of the wallet here:
https://www.blockchain.com/explorer/addresses/btc/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
0002146273a3774b3828effff3382000someGarbageSecretThatsActuallyIs{https://youtu.be/eBGIQ7ZuuiU}EnctyptedUsingARandom4096BitStringAsPassword
- Anyone can point to a random link on blockchain.com
- the encrypted secret can contain anything
Thoroughly evaluating security/cryptography takes deep expertise and a lot of time. You're not going to elicit that without more money, impact/fame, or technical excellence.
- Money: The original bounty was $400. An expert can probably earn $400 an hour just to investigate something, without needing to completely break it.
- Impact/fame: Barely anyone uses this project. There are tons of other tools and services that are more widely used.
- Technical excellence: There's no evidence of anything clever or interesting.
For example, researchers around the world spend tons of effort analyzing the algorithms in the various NIST cryptography competitions. There's significant impact/fame and clear evidence of technical excellence. But if some rando offers a $10k bounty for their encryption algorithm, it's not going to get the required level of scrutiny.
Plus, the bounty is just for the encryption mechanism. With security, it's usually the other moving parts that cause issues, especially in how they interact with human behavior. Phishing works without needing to break TLS, DKIM/SPF, browser sandboxing, etc.
(I read an article ~5-10 years ago by a security/crypto researcher that said basically this, but sadly I can't find it anymore.)
I still think it's great when people build things like this and when they offer any kind of bounty. I just worry that the presence of an unclaimed bounty might mislead people into overestimating the level of security.
I'm just sharing a little hack I came up with. I hope some people add it to their toolchain (not my specific implementation, the idea in general).
And offering a bounty seemed like a fun things to do, which may also catch some shallow bugs, reward the hunter, and shame me publicly :-)
[1] https://mprimi.github.io/portable-secret/examples/bounty.htm...
I don't think of it as PR/Ad. It's a bounty. If you put in time to find a flaw, you deserve at least that much (and I'll give you more if you help me fix it).
Security by obscurity is real, there's nothing secret about defining the problem space in which your attackers can search.
This is what the bounty is for. I just hope whoever cracks it lets me know how they did it and how hard it was.
This is what a bounty is, no?
It's a cute marketing gimmick, that's about it.
if using a crypto algorithm also counts as "rolling your own crypto" then what's left? just don't encrypt anything, ever, because HN says we shouldn't roll our own?
I'm not a crypto expert, I'm just telling you what I've been reading on HN for the past few years.
The difference is, you're sort-of allowed to f up if it's an intelligent mistake that teaches the creators of misuse resistant libraries a thing or two about where they went wrong. If OTOH you're clearly just yoloing it, introducing your pseudo-math BS into the mix, or intentionally deviating from best practices or breaking it, then it's on you.