1.1-1.2 and 3.1, due on August 29

1. (Difficult) I think these sections would make a lot more sense if there were some examples. For instance, "Here's the plaintext: It is said that one day... and here it is ciphertext: Kn ki iuky npun ... and the encryption key is: k=i n=t, i=s, ..." because I thought I got it and now I'm not sure. Are the encrpyt and decrypt texts or keys?

Also, how is the algorithm of encryption different than the key? Because Kerckhoff's principle says Eve knows the algorithm of encryption but not the key. What's the difference? 

2. (Reflection) I did not know that cryptography was such an art. I should have, but never thought about it. There is a lot of theory, techniques, vocabulary, ... about it. Wow!