The key points from this module are:
Cryptography is the science of keeping data secure from unwanted and untrusted entities.
The main objectives of cryptography are:


Privacy


Authenticity


Integrity


Fundamental problems addressed by cryptography are:

Key agreement problem
Secure Communication problem

The two main types of cryptographic primitives are:

Symmetric key primitives
Asymmetric key primitives

The four most common types of attack models are:

Ciphertext-only attack (COA)
known-plaintext attack (KPA)
Chosen plaintext attack (CPA)
Chosen ciphertext attack (CCA)

Kerckhoffs' Principle states: A cryptosystem should be secure even if everything about the system, except the key is public knowledge.
The interpretation of Perfect Security suggests that the probability of knowing a plain-text remains the same before and after seeing the cipher-text