The Side Channel

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9:49 AM

Q: Composition of cryptographic hash functions

I've stumbled upon many opinions, so I ask about them myself. Let $H(x)$ and $F(x)$ be hash functions. is $H(F(x))$ or $F(H(x))$ safer than $H(x)$ or $F(x)$ is $H(F(x))$ or $F(H(x))$ safe when $H(x)$ or $F(x)$ becomes vulnerable is $H(H(x))$ safer than $H(x)$ Background Doing my own research, I...

6 hours later…

Crypto HNQ

3:39 PM

Q: How is MitM attack prevented when complete session is hijacked?

Lets say there is mutual authentication between a client which connects to a server on an otherwise unsecured TCP channel. Both parties create a random challenge and the other side answers with a keyd-hash, based on a pre-shared symmetric key. $$C\rightarrow open \,\, connection \rightarrow S$$ ...