Test Review

I think the most important things we have learned is the names and algorithms for encrypting using different ciphers. The most common of the things we've learned are DES and AES, so we should probably know those.

I expect proofs and questions about what type of attack will work on which cipher.

I need to study more about the modes of operation and the things that we studied this week.

Sections 5.1-5.4

It was interesting to read that AES was chosen from 15 crypto-systems. I wonder what was different and inherently better about AES than the other options.

It understood most of the reasons that AES was designed in this way, but i had one questions. Why is it that if you change one input byte all four outputs are changed but if you change two, then at least three are changed?

Questions

Each homework assignment took around 5 -7 hours. Each assignment was a learning opportunity. I felt that i knew where to look when i struggled with the assignments because of the reading and the lectures  introduced the concepts but the assignments required me to delve in deeper.

I think lectures make all the difference. Each unclear concept from the reading is clearly explained in class.

I need to start the assignments earlier in the week in order to not be rushed to finish them.

Section 3.11

I found this section very similar to abstract algebra. It was interesting to see how finite fields apply to cryptography.

I was confused by the GF field and its properties.

Section 4.5-4.8

I was interested to learn a little history about the breaking of DES.  It is clear how hard it is to change the standard in encryption because of the many problems it solves. It is interesting to read about salt and how it can make DES more secure. I understand a little more why my passwords must be secure.

It was difficult to understand the different modes of operation, such as Cipher Feedback and Output feedback. I don't understand how the functions work.

Sections 4.1,4.2,4.4

I found the discussion on DES very interesting. I like how the many permutations kept it secure for so long.

I was thoroughly confused by the example given to illustrate the DES algorithm.

Section 2.9-2.11

I was thoroughly intrigued by the one way function that creates randomness. I am interested to understand more about random numbers and how to find them.

On the other hand, i was thoroughly confused by LFSR sequences and how the recurrence formula's describe them.

Sections 3.8, 2.5-2.8

The Sherlock Holme's story was very interesting and it was interesting to read how each of the ciphers discussed can be broken.

I do not understand the concept of binary, so it was difficult to follow the section about binary.

Section 2.3 Due September 10

I thought it was very interesting how using process of elimination and the frequency of letters, the encryption key could be found fairly easily. But this method seems to rely heavily on the frequency being known and perfectly followed.

I was not able to understand the second method for finding the key. How did the knowledge that the larges dot product .0713 lead the author to the first shift being 2??