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An Intensive Introduction to Cryptography

intensecrypto.org

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Re: An Intensive Introduction to Cryptography

#11

Post by Kalium »

lifeisstillgood wrote: post #10
tom-c wrote: post #7

Earlier quoted context omitted.

The interesting thing about Crypto performance tuning is that you really have to ensure that no logical path does a different amount/kind of work than another(i.e. no short circuiting). I used to not think much of it until I saw an RSA private key recovered via acoustic analysis of capacitor whine due to a short circuit condition in a function to multiply two large numbers.(this was using a recent release of openssl)…

seems obvious, but just checking that they needed (acoustic) access to the machine performing a calculation with private key?

Yes, though generally such attacks can function from at least a few feet - sometimes 20-ish - away.

So some access, though less than you might guess.

Re: An Intensive Introduction to Cryptography

#14

Post by bradleyjg »

j7ake wrote: post #3

What is a typical path for those who want to follow this as a career? Is it mostly PhDs in academia? Or governments? Or industries? How do they fall as a distribution?

Edit: see tptacek’s reply. He knows that corner of the world far better than I do.

From my external observation there are two main career paths: the math side and the coding side (djb does both, but he’s djb).

For the math side, a PhD is the most likely path to break in. If you are some kind of autodidact genius and were to publish a theoretical attack on an important crypto system, you could probably get involved without a PhD.

On the coding side apparently the best way to break into writing secure code is to first break insecure code+. I don’t know if this is a reasonable filter or not, but it seems to exist. Some people are perfectly happy to stay on the break code side of things and never move to the write code side. If you think you might like this sort of thing check out the cryptopals ctf that should be floating around.

+ meaning find a side channel, some place where a nonce is reused, etc, etc. If you find a way to factor quickly in a particular ECC ring that’s the prior paragraph.

Re: An Intensive Introduction to Cryptography

#15

Post by tptacek »

j7ake wrote: post #3

What is a typical path for those who want to follow this as a career? Is it mostly PhDs in academia? Or governments? Or industries? How do they fall as a distribution?

Most people with full-time crypto jobs have graduate degrees in cryptography. FAANG-type tech giants hire single-digits crypto people per year. What we did at the NCC Cryptography Services practice (a team of non-PhDs working almost entirely on offensive crypto) was pretty anomalous --- and that team is now led by Thomas Pornin, who has a graduate degree in cryptography. :)

Re: An Intensive Introduction to Cryptography

#16

Post by tptacek »

bradleyjg wrote: post #14
j7ake wrote: post #3

What is a typical path for those who want to follow this as a career? Is it mostly PhDs in academia? Or governments? Or industries? How do they fall as a distribution?

Edit: see tptacek’s reply. He knows that corner of the world far better than I do. From my external observation there are two main career paths: the math side and the coding side (djb does both, but he’s djb). For the math side, a PhD is the most likely path to break in. If you are some kind of autodidact genius and were to publish a theoretical attack on an important crypto system, you could probably get involved wi…

Software security people do not generally move into full-time cryptography jobs --- or, for that matter, test much cryptography at all (more's the pity). The people who code crypto generally have crypto degrees.

Re: An Intensive Introduction to Cryptography

#18

Post by auslander »

auslander wrote: post #12
j7ake wrote: post #3

What is a typical path for those who want to follow this as a career? Is it mostly PhDs in academia? Or governments? Or industries? How do they fall as a distribution?

Don't trust anyone. (c) Feynman

https://stepsandleaps.wordpress.com/2017/10/17/feynmans-brea...

Re: An Intensive Introduction to Cryptography

#19

Post by exikyut »

tom-c wrote: post #7
eismcc wrote: post #5

Earlier quoted context omitted.

I worked on the Windows crypto team for a few years. Learned a ton about this area. Most of the work, however, is plumbing. Only a tiny fraction of crypto work is actually on algorithms and that’s mostly performance related.

The interesting thing about Crypto performance tuning is that you really have to ensure that no logical path does a different amount/kind of work than another(i.e. no short circuiting). I used to not think much of it until I saw an RSA private key recovered via acoustic analysis of capacitor whine due to a short circuit condition in a function to multiply two large numbers.(this was using a recent release of openssl)…

If this "I saw" has any further public details, I'd absolutely love to learn more, and I'm pretty sure others would as well.

In particular, I'm especially interested in electrical or real-world attacks - such as capacitor whine! - that can be applied a weakened security situations like asymmetric logic/branching. I vaguely recall CPU voltage fuzzing is a thing, I want to go learn more about that at some point.

I'm only familiar with eg ultrasonic accoustic airgap attacks (like MOSQUITO, eg https://securityaffairs.co/wordpress/70192/hacking/mosquito-...).

Re: An Intensive Introduction to Cryptography

#20

Post by blattimwind »

exikyut wrote: post #19
tom-c wrote: post #7

Earlier quoted context omitted.

The interesting thing about Crypto performance tuning is that you really have to ensure that no logical path does a different amount/kind of work than another(i.e. no short circuiting). I used to not think much of it until I saw an RSA private key recovered via acoustic analysis of capacitor whine due to a short circuit condition in a function to multiply two large numbers.(this was using a recent release of openssl)…

If this "I saw" has any further public details, I'd absolutely love to learn more, and I'm pretty sure others would as well. In particular, I'm especially interested in electrical or real-world attacks - such as capacitor whine! - that can be applied a weakened security situations like asymmetric logic/branching. I vaguely recall CPU voltage fuzzing is a thing, I want to go learn more about that at some point. I'm on…

http://www.cs.tau.ac.il/~tromer/acoustic/
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