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Hot answers tagged cryptanalysis

6

The point of cryptography is having algorithms that are secure even when the attacker knows them. Google security by obscurity to see why it's bad. I'll add the following based on otus comment. Python can be reverse engineered, so you can't hide your algorithms. Basically, if someone can run your code, they can reverse engineer the algorithms. The point of ...

4

Without the specific reference I can't be sure this is what you are talking about, but generally a "long message" attack is a way to defeat second preimage resistance with less complexity than expected. It uses a time-space tradeoff to find a second preimage with complexity $2^{n/2}$ for a $n$-bit hash function (normally you would expect $2^n$). In the ...

4

A long message is a message that, when padded, is longer than the block size of the hash function. That means that the hash function has to process the message in parts and keep track of state somehow, which may allow for attacks. Such attacks would not apply to messages shorter than the block size, and may additionally require a large number of blocks to ...

2

Python is a scripting language, so if you've got the program, you usually also have the source code. So you don't even have to reverse-engineer. That doesn't matter much for two reasons: other languages are pretty easy to reverse engineer (or they are complex for both the programmer and the attacker); the algorithm does not have to be kept safe anyway, due ...

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