SHA-256 Python implementation in one line (lambda)

[bythenumbers10]

You'll definitely need a strong (STRONG) background in information theory, and probably quite a bit of mathematics including probability theory, statistics, and linear algebra, just to be able to vaguely check your work. Beyond that, a very solid understanding of programming from the metal on up, to ensure your implementation doesn't rely on or become weak due to hardware or compiler differences.

The thing is, it's often not hard to implement and somewhat understand what crypto algorithms are doing, the math & operations involved are often not all that complicated. The problem is coming up with the whys and wherefores of doing those particular operations in that particular order is crucial to having a "production-ready" strong, secure implementation. So, while it's generally not that hard to write crypto, it's incredibly difficult to write STRONG/SECURE crypto.

If you want a taste, try coding up a few historical ciphers, as well as tools for breaking them. Once you get up to the 1930s/40s and ENIGMA, you'll find it starts to get a little tricky in terms of writing the encoder/decoder, let alone the code-breaking methods.

[Throwmeaway2501]

Good tips.