How much of Probability do I need to know to study Cryptography? I have just started MSc in Computer Security. I didn't study probability before. Now, I have some short time to complete my MSc semester.

What are the minimum topics from 'Probability' do I need to know to complete my Cryptography course?
Not much. All you need can be found in any "Intro. to cryptography" book such as Katz/Lindell. In particular, you don't need any of the fancy measure-theoretic stuff since in cryptography you only work with discrete distributions.