So, you want to crypto
blog.existentialize.com
So, you want to crypto
1–10 of 75 posts
Re: So, you want to crypto
#2TL;DR - If you want to do crypto then learn crypto.
If you want to learn crypto and do crypto then certainly start with this. Then, when doing crypto...practice. Build it and reach out and ask for help and talk to people who know what they are doing and learn from them. Ask them about problems you encountered and ask them about the best ways to solve them...otherwise you will continue to make the same mistakes.
Re: So, you want to crypto
#3>Do not let users use your product until it's been vetted.
Its OK to let them use it so you can have a large user-base to test with, you just need to explain to them that it isn't proven secure. As in, explicitly tell them that they are under no circumstances to use it with sensitive information.
Playing around with cryptography is the only way to learn it, you just have to remember to tell people that playing is exactly what you are doing.
Re: So, you want to crypto
#4I think this quote from the article perfectly sums up the dangers of amateur cryptography:
"Cryptography isn't something you can iterate on until you get it right, because you'll never know if you do."
Re: So, you want to crypto
#5Surely the correct answer is "just use keyczar"? At least 99% of the time.
Re: So, you want to crypto
#6>Both Applied Cryptography and the Handbook of Applied Cryptography are great resources, although they're a little dated now. ... Step one is to read Cryptography Engineering. This is not optional. Read it. It is a fantastic book that details how to use cryptographic primitives.
It seems kinda superfluous to mention Applied Crypto when the real reco is to read Cryptography Engineering. I'd almost wonder if it would be better to direct people away from Applied Crypto...
Personally, I found Applied Cryptography to be so-so at best. Practical Cryptography was a breath of fresh air in comparison.
Re: So, you want to crypto
#7article mentions nothing-up-my-sleeve numbers, so a topical reminder that the permutation for md2 (and rc2 apparently) is still unexplained (despite being "derived from pi") - http://crypto.stackexchange.com/questions/11935/how-is-the-m...
for all you conspiracists - this was designed by rivest, the r in rsa, now famous for cooperating with nsa... (i don't really believe that the permutation is a backdoor, but i would like to know how it's derived - rivest is famous for elegant algorithms, and for the life of me i can't find a simple, neat way to get those numbers from pi)
Re: So, you want to crypto
#8If you want a more "theoretical" look at the theory, Introduction to Modern Cryptography by Jon Katz and Yehuda Lindell is a great book. Also good (but my copy had many printing errors) is Foundations of Cryptography by Oded Goldreich.
Re: So, you want to crypto
#9>Do not let users use your product until it's been vetted. Its OK to let them use it so you can have a large user-base to test with, you just need to explain to them that it isn't proven secure. As in, explicitly tell them that they are under no circumstances to use it with sensitive information. Playing around with cryptography is the only way to learn it, you just have to remember to tell people that playing is exa…
But how many people are going to be interested in a crypto product which is unproven? Sure, perhaps a few technical types will give it a whirl, but most people just want something that works. If I'm in the market for something like this I'm certainly not going to use a product with a big disclaimer stating "Hey, we don't really know if this works yet, but help us test it out!" This is mission critical stuff, not some new URL routing framework.
Re: So, you want to crypto
#10>Do not let users use your product until it's been vetted. Its OK to let them use it so you can have a large user-base to test with, you just need to explain to them that it isn't proven secure. As in, explicitly tell them that they are under no circumstances to use it with sensitive information. Playing around with cryptography is the only way to learn it, you just have to remember to tell people that playing is exa…
Two things.
First, while "playing around with cryptography" may be the only way to learn it, building cryptographic systems is just about the worst way to learn. Professional cryptographers start by cryptanalyzing targets and use that experience to inform their future designs. On the other hand, veteran implementors who have never taken the time to learn how to break crypto turn out protocols and designs that are repeatedly broken. You can see that right now with TLS and the TLS working group, which still hasn't fixed MtE block ciphersuites because veteran implementors can't get it through their heads that MtE is a design flaw.
Don't learn by building. You need to learn by breaking.
Second, more than one project has done the tightrope walk of telling their users "this isn't really safe" but then misleading (innocently or not) non-savvy users into trusting them. One project made it clear that their system wasn't "ready" to defend against nation-state adversaries... but then suggested that maybe it would be good enough for journalists, and even promoted it at an event for teaching journalists cryptography. It was later comically broken.
Be honest with yourself. Crypto doesn't get beta-tested into resiliency. Strong systems start out strong. If you're building something because its your dream to thwart the NSA, don't kid yourself into thinking that you'll get there by first protecting people's Warcraft clans.