From the course: Symmetric Cryptography Essential Training

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The importance of randomness to cryptography

The importance of randomness to cryptography

From the course: Symmetric Cryptography Essential Training

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The importance of randomness to cryptography

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- [Narrator] One of the big assumptions we made in the last video was that the cryptographic keys we're using are generated uniformly at random. If they're even a little predictable, our security assumptions no longer hold, and the key is effectively shorter. What does it mean for something to be random, though? There are two approaches to producing unpredictable numbers that don't follow any patterns. We distinguish between pseudorandom numbers and truly random numbers. The first is not truly random, but pseudorandom. Pseudorandom number generators, PRNGs, which we briefly mentioned in a previous chapter, do indeed look random by most metrics. These are difficult but not impossible to predict. They're deterministic algorithms. This means that they'll do the same thing every time they're run with the same inputs. In that sense, they're predictable. It may be difficult, but definitely not impossible. PRNGs work fine when the randomness is used to roll dice for a game or for running a…

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