Crypto 101 – Introductory course on cryptography (2017)

pona-a 224 points crypto101.io

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baxtr

>Fortunately, we donʼt have an algorithm that can factor such large numbers in reasonable time. Unfortunately, we also havenʼt proven it doesnʼt exist. Even more unfortunate is that there is a theoretical algorithm, called Shorʼs algorithm, that would be able to factor such a number in reasonable time on a quantum computer. Right now, quantum computers are far from practical, but it does appear that if someone in the future manages to build one thatʼs sufficiently large, RSA becomes ineffective.

Can anyone comment on how close we are to having Shor's algorithm on a quantum computer? Is feasible like the moon landing was in 1962 when Kennedy announced that "We choose to go to the Moon" (hard, but possible with a lot of money).

Or is it still something that we have no clue how to get to?

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ctz

https://pqcrypto2025.iis.sinica.edu.tw/slides/Invited3.pdf

edit: video if you prefer - https://www.youtube.com/watch?v=nJxENYdsB6c

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baxtr

So it’s not like the moon landing since the horizon is much longer than a decade.

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z3phyr

I think cryptanalysis as a discipline is not massively funded. All of the cryptography is only as strong as the collective failure of all human intelligence so far to break it.

Most people consider cryptography as a "solved" problem, but I don't think it is. I am sure if enough cryptologists try algorithmic methods and are well compensated for it, they will likely find algorithmic weaknesses (and invent new kinds of mathematics) that can bring down complexity of solving such schemes, even before we have real and functional Shor machines.

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thaumasiotes

I think cryptanalysis as a discipline is not massively funded.

Really? That would be a change.

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z3phyr

I guess massively is the relative word. But I will stand by the claim that we can discover/invent new mathematical methods that can aid in cryptanalysis, if not directly by cryptographers, then by some adjacent field.

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anorphirith

this is the type of crypto i like

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teleforce

Thanks for the link.

You can download this entire Handbook of Applied Cryptography for free^[1].

Recently the authors also provided online course and video namely:

- Cryptography 101: Building Blocks (fundamental cryptographic primitives)^[2]

- Cryptography 101: Real-World Deployments (PKI, TLS, Bluetooth, AWS, Signal)^[3]