Is Diffie Hellman key exchange based on one-way function or trapdoor function? I have a question for my information security lab, which I am not able to find online.
As the title says, is Diffie Hellman key exchange based on a one-way or a trapdoor function?

In case of RSA I would say it is based on a trapdoor function, since it is hard to factorize the modulo, if you don't know p and q.

Is Diffie Hellman also based on a trapdoor function, since it is hard to reverse the discrete logarithm, if you don't know the secret key?
No, the mathematical problem that is used for Diffie-Hellman is the Diffie-Hellman problem or DHP which is different from the trapdoor function that is behind RSA.

One way functions are for instance cryptographically secure hash functions.