How does the concept of a "public key" and a "private key" work together in public key encryption?

Explain the significance of the Caesar cipher in the history of encryption.

What does the term "out of band" imply? In symmetric encryption, why is it required to swap keys out of band?

How are symmetric and asymmetric key encryption different?

Is it true that using symmetric encryption techniques comes with a set of advantages as well as a set of disadvantages? What kinds of things should be taken into account before deciding on a certain method of encryption to put into practise?

What are some of the drawbacks of employing symmetric encryption when it comes to the maintenance of the key?

What are the disadvantages of symmetric encryption in terms of key management?

What are the downsides of symmetric encryption's key management?

Calculate the key space for 128-bit keys and compare that to the key space for 10-character passwords (lower case English alphabetic, upper case English alphabetic, 10 digits and 14 special characters are allowed). How many characters does a password following the above rules must have to achieve the same or better security as 128-bit random keys if the passwords would be chosen randomly?

Asymmetric and symmetric encryption schemes have equal benefits and drawbacks. How does one decide what kind of encryption to use and what factors need to be taken into account?