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An Intensive Introduction to Cryptography

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Re: An Intensive Introduction to Cryptography

#21

Post by JoachimSchipper »

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…

For the specific case of acoustic signals, see https://www.tau.ac.il/~tromer/acoustic/. For "CPU voltage fuzzing", Google "glitch attack" (e.g. https://wiki.newae.com/Tutorial_A2_Introduction_to_Glitch_At... ) or, more generally, "fault attacks".

The relevant academic community can be found around https://ches.iacr.org/2018/program.shtml.

(I work for a company building high-assurance crypto appliances for the Dutch government, so I have a professional interest.)

Re: An Intensive Introduction to Cryptography

#22

Post by tom-c »

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…

I couldn't find the specific lecture/demo that I went to, but I found a video by the same guy with a similar presentation elsewhere. Coincidentally he's also one of the researchers who published the original paper on Meltdown

https://youtu.be/DU-HruI7Q30

Re: An Intensive Introduction to Cryptography

#24

Post by baby »

tptacek wrote: post #15
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. :)

(Actually half of our team has a phd in crypto atm)

Re: An Intensive Introduction to Cryptography

#25

Post by tptacek »

tptacek wrote: post #15
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. :)

Followup: I was asked offline, with a bunch of counterexamples, whether you need to go to school to be good at crypto. I want to be clear that I'm offering career advice here, not technical advice. For the record, I have something like 2 credit hours towards an LAS bachelors from 1995 and nothing else. :)

It's just my observation that people with full-time jobs in cryptography all (with some exceptions that I think prove the rule) have graduate crypto degrees. I'll venture a guess: there are more crypto PhD's interested in jobs in industry than there are full-time crypto jobs in the industry to give them.

I think people probably underestimate just how specialized serious cryptography is as a practiced skill in the industry.

(Also: I mean "crypto" as in "cryptography". Lord knows what's going on in the Monero mines.)

Re: An Intensive Introduction to Cryptography

#26

Post by Ar-Curunir »

This is a class for folks trying to understand the theory behind modern cryptography rigorously; it focuses on the theoretical foundations of crypto like one way functions and PRGs and builds up from them.

This course will not teach you how to implement crypto, but the material here is incredibly important to understanding the abstractions and reasoning behind modern cryptographic constructions, and is a prerequisite to becoming good at implementation aspects of crypto.

Re: An Intensive Introduction to Cryptography

#27

Post by malgregator »

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?

If you are interested in the boring part, so not how algorithms are invented and implemented, but more on the real world usage, I have written a blog "Commercial Cryptographic Key Management in 2018", where I am explaining a little bit about the hardware, people and processes behind it. https://www.malgregator.com/key-management.html

Re: An Intensive Introduction to Cryptography

#28

Post by distrorepoman »

a word of warning. off the page textbook crypto examples are not a good crypto scheme you have to think like a bank robber to start securing your bank. if you think like a banker then you will try to cut costs and corners to make revenue.

addendum > Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can't break. It's not even hard. What is hard is creating an algorithm that no one else can break, even after years of analysis. And the only way to prove that is to subject the algorithm to years of analysis by the best cryptographers around.

good crypto cant be broken by knowing the algo thats why closed proprietary crypto is POS

addendum 2 )

this makes the case for open source so there are multiple perspectives rather than ECHO CHAMBERS bcz when it comes down to it you can talk yourself into thinking anything is great when it is your own pet theory.

BTW im working around the posting too fast BS so thats why the addendums to parent post.

================================= ALSO off topic but, concerning:

Detecting Screen Content via Remote Acoustic Side Channels

{https://www.cs.tau.ac.il/~tromer/synesthesia/}

every time a pixel changes it makes a UHF+ EMF chirp every time a bus channel makes a bit state transition it makes a UHF+ chirp if you evesdrop the EMF radiation preserve it and analyse your data then you can reconstruct EVERYTHING that the hardware is doing not just the display screen.

Re: An Intensive Introduction to Cryptography

#29

Post by ChrisSD »

distrorepoman wrote: post #28

a word of warning. off the page textbook crypto examples are not a good crypto scheme you have to think like a bank robber to start securing your bank. if you think like a banker then you will try to cut costs and corners to make revenue. addendum > Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can't break. It's not even hard. What is hard is creating an alg…

Although be wary of how far even that can take you. As Bruce Schneier has said[0]:

> Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can't break. It's not even hard. What is hard is creating an algorithm that no one else can break, even after years of analysis. And the only way to prove that is to subject the algorithm to years of analysis by the best cryptographers around.

> If I have any contribution to this, it's to generalize it to security systems and not just to cryptographic algorithms. Because anyone can design a security system that he cannot break, evaluating the security credentials of the designer is an essential aspect of evaluating the system's security.

[0] https://www.schneier.com/blog/archives/2011/04/schneiers_law...

Re: An Intensive Introduction to Cryptography

#30

Post by pkcsecurity »

Another great crypto resource (though it's really an intro course) that's out there is the Cryptography course on Coursera: https://www.coursera.org/learn/crypto. It's taught by Dan Boneh who, in addition to being a genius, also happens to be incredibly talented at explaining crypto concepts in a way that leads to deep understanding. It's a great treat watching him write out and explain different proofs from memory.

After taking these two crypto courses, I signed up for CS155 https://crypto.stanford.edu/cs155/, which is his undergrad class on security at Stanford (they were offering it through their professional center, I don't think they still offer it, which is a bummer)

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