71–80 of 92 posts
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> It’s absolutely worth it to roll your own crypto if you want to learn from it. It's essentially a waste of your time. Because of Schneier's Law: "Any person can invent a security system so clever that she or he can't think of how to break it". The thing that you might learn from, if you put the work in, would be breaking other people's stuff. Ideally you would find something that's actually in use and vulnerable en…
How dare you.
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> It’s absolutely worth it to roll your own crypto if you want to learn from it. It's essentially a waste of your time. Because of Schneier's Law: "Any person can invent a security system so clever that she or he can't think of how to break it". The thing that you might learn from, if you put the work in, would be breaking other people's stuff. Ideally you would find something that's actually in use and vulnerable en…
"""It's essentially a waste of your time.""" Strongly disagree. I'm pretty sure rolling your own crypto will strengthen your understanding of crypto (and potential flaws) a lot. Obviously don't use it in production but by all means, do it for the sake of learning. How can this be a waste of time? That's like saying "never implement a search/sort algorithm, just use libraries"...yeah sure use libraries but also implem…
RSA is really good example of this: you can "implement" RSA in Python in an hour, and your understanding will include some of the mathematical fundamentals (prime generation, modular exponentiation, &c.). What it won't include is why or how each of those fundamentals comes with a laundry list of caveats that can completely break any scheme that uses your particular implementation of RSA.
I second the recommendation for cryptopals, as well as all of the resources that Matt Green lists[1].
[1]: https://blog.cryptographyengineering.com/useful-cryptography...
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> you shouldn't use your (or their) self-made cryptography in production Absolutely, and that was the very first thing I thought when I saw the title. For some reason I've got the "don't roll your own crypto" commandment heavily ingrained into my brain (even though I've never been in any context where I might have tried), together with "don't let the frying pan handle stick out over the edge of the cooker in case a k…
"don't roll your own crypto" is good advice, but it's also against the hacker ethos. It's another way of saying "you'll never really understand this so don't try, just rely on a mysterious cabal of experts". May be true, but not exactly a great message.
In general, I think DRYAC is excellent advice, and that we should apply similar reasoning to unsafe programming languages. And that is not to say that people shouldn't use them; only that we, as a community, should be making ourselves more half-ass-resistant.
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It’s absolutely worth it to roll your own crypto if you want to learn from it. I feel like there is almost a stigma against articles like these because we’ve all been conditioned so much to avoid even thinking about it lol. I did some deep dive into AES and RSA at some point in a distant past, it was a learning experience that to this day allows me to make much better decisions when choosing algorithms.
> It’s absolutely worth it to roll your own crypto if you want to learn from it No. If you want to "learn from it", the first thing you should do is buy a copy of Bruce Schneier's Applied Cryptography . Just reading (and fully understanding !) that book will alone put you in a position where you already know more about cryptography than 90% of other people. If after that you still want to play around with rolling you…
The purpose of this is to learn how AES works, not to write a library you would actually use.
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It’s absolutely worth it to roll your own crypto if you want to learn from it. I feel like there is almost a stigma against articles like these because we’ve all been conditioned so much to avoid even thinking about it lol. I did some deep dive into AES and RSA at some point in a distant past, it was a learning experience that to this day allows me to make much better decisions when choosing algorithms.
> It’s absolutely worth it to roll your own crypto if you want to learn from it. It's essentially a waste of your time. Because of Schneier's Law: "Any person can invent a security system so clever that she or he can't think of how to break it". The thing that you might learn from, if you put the work in, would be breaking other people's stuff. Ideally you would find something that's actually in use and vulnerable en…
Someone has to write those libraries.
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"""It's essentially a waste of your time.""" Strongly disagree. I'm pretty sure rolling your own crypto will strengthen your understanding of crypto (and potential flaws) a lot. Obviously don't use it in production but by all means, do it for the sake of learning. How can this be a waste of time? That's like saying "never implement a search/sort algorithm, just use libraries"...yeah sure use libraries but also implem…
There are a lot of subdomains within cryptography where "rolling your own" will not meaningfully strengthen your understanding of the underlying concept. RSA is really good example of this: you can "implement" RSA in Python in an hour, and your understanding will include some of the mathematical fundamentals (prime generation, modular exponentiation, &c.). What it won't include is why or how each of those fundamental…
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There are a lot of subdomains within cryptography where "rolling your own" will not meaningfully strengthen your understanding of the underlying concept. RSA is really good example of this: you can "implement" RSA in Python in an hour, and your understanding will include some of the mathematical fundamentals (prime generation, modular exponentiation, &c.). What it won't include is why or how each of those fundamental…
Right, but if you've improved your knowledge of the fundamentals by rolling your own RSA you'll be in a much better position to fully understand detailed articles that explain those caveats.
RSA is a particularly easy punching bag in this regard, but I think it's true generally (and is generally becoming more true, as we see increasingly clever sidechannels and oracles).
Edit: That being said, I want to moderate my position by saying that I don't think there's anything wrong with playing around with cryptosystems in an attempt to learn them. I do it! I think the risk that people talk about when they say "DRYAC" is that engineers will take their relatively painless experience getting it 10% right in their spare time and think they can get it 100% right without an asymmetric amount of additional effort.
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> It’s absolutely worth it to roll your own crypto if you want to learn from it. It's essentially a waste of your time. Because of Schneier's Law: "Any person can invent a security system so clever that she or he can't think of how to break it". The thing that you might learn from, if you put the work in, would be breaking other people's stuff. Ideally you would find something that's actually in use and vulnerable en…
If no one is allowed to roll their own crypto, even just to learn how it works (and not use it for anything), then how does one become one of those exalted crypto experts who is allowed to create the libraries that everyone else who doesn't roll their own crypto uses? Someone has to write those libraries.
Now, use what you learned (from breaking stuff) to make something which resists the attacks you learned. Congratulations, you have improved the state of the art. This is how actual experts (not sure any of them are or should be "exalted") did it.
† Bad, but, in many cases, very real. Because people stubbornly will not learn this lesson and keep rolling their own we are still finding broken garbage in the real world it's just becoming gradually rarer.
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"don't roll your own crypto" is good advice, but it's also against the hacker ethos. It's another way of saying "you'll never really understand this so don't try, just rely on a mysterious cabal of experts". May be true, but not exactly a great message.
I think it's closer to "don't think you can half-ass your way into an understanding," rather than "you'll never be able to understand this." That "cabal of experts" all had to learn at some point, too. In general, I think DRYAC is excellent advice, and that we should apply similar reasoning to unsafe programming languages. And that is not to say that people shouldn't use them; only that we, as a community, should be…
Granted, this is a bad idea when it comes to nuclear engineering. But it's sad when we say it's bad for software engineering, even crypto.
The fact that you want to apply that to C programming is really sad. That's effectively saying that people can play with web apps, but not operating systems.
I am not saying you are wrong. Just that you're no fun at all.