questions, due september 30

the homework assignments have usually taken 1-2 hours, which isn’t all that bad. the lectures are usually pretty helpful and prepare me for the homework. the reading prepares me sometimes, but sometimes the reading is completely over my head, so it’s not all that helpful. but it can be.

i learn best through examples, because then i see the steps to solving the problem and can follow them later. doing examples in class has definitely contributed to my learning.

recently, i feel like i’ve been a bit behind in most of my classes, and i have frequently found myself scrambling to get the homework done during class. i need to remember that i have until 5 to do the homework, and that i need to pay better attention to the lecture, because it is usually pretty helpful.

3.11-3.11.2, due september 27

i have trouble with dividing by polynomials. i remember learning about how to do that, but i just need to practice it a little. i’m not very confident in my abilities to do that, but with practice that will come. but i did understand how to do the euclidean algorithm with polynomials—it will just be difficult to do division by polynomials.

it’s interesting for me to see how polynomials and binary numbers are used in the same method. i’ve always considered those two completely unrelated, and i’ve never seen them used in the same process/method. i’m actually kinda surprised they can be. a lot of work goes into creating these processes.

4.5-4.8, due september 25

these sections were a little rough for me. i think the hardest part was just keeping the modes of operation separate. they keep running together in my mind, and it’s hard to distinguish them. hopefully as i work with them, i’ll be able to tell one apart from the other.

i thought the history of breaking DES was interesting. it’s interesting to see the developments in code-breaking over time. that’s also probably because i can actually understand it because it’s a story, not the explanation of a code. i also liked that the abbreviation for counter mode is CTR. (that’s me being super mormon, but that’s okay)

4.1, 4.2, 4.4, due september 23

i’m a little confused on how the s-boxes work; they don’t really make sense to me. i usually get confused when we start talking about bits, because i’m not sure i know exactly what that means. i know i saw this a lot, but i usually don’t really understand this stuff until i go to class or do examples of it.

something that struck me was that a long time ago, the DES was resistant to differential cryptanalysis. i take that to mean that it was relatively unbreakable. but now it’s becoming outdated, which i take to mean that it’s becoming breakable. i just think it’s interesting that we are now able to break codes we haven’t been able to in the past!

2.9-2.11, due on september 20

the LFSR was confusing for me, as was the blum-blum-shub pseudo-random bit generator. maybe i missed it, but i wasn’t totally clear as to what the least significant bit was. it could be that it literally is the least significant bit, as in the one of least importance. i don’t think that’s really what it is though.

it still blows my mind that there are unbreakable codes. every time one is mentioned, i just can’t process it. i would love to be someone that came up with one, but i don’t think i have the ability to. most codes are unbreakable for me! it’s just crazy to think that there is a method that has created a one-time code. i can’t wrap my head around it. people are so cool!

3.8, 2.5-2.8, due on september 17

i’ll be honest. i read this pretty late, so i got lost a lot. it probably doesn’t help that i’m not the best with matrices or with binary numbers. if i focus hard and practice, i am sure i will get it.

the playfair cipher sounds really cool, but i’d need to write/try it out myself to actually understand it. but my favorite part was probably the sherlock holmes part, and now i really want to read the sherlock holmes books. besides, who doesn’t love sherlock holmes?

2.3, due on september 15

i got a little lost when the book was describing how to decipher the vigenere cipher. vectors always confuse me, so when they’re brought up for any reason, i tend to get a little lost. i was also confused about the shifts of the letters and how that worked.

although, i thought the idea behind this cipher was a pretty good one. i thought it would be really hard to decipher something where the letters were shifted based on where they appeared, not what letter it was. i guess i kinda understood the cipher, but when they were describing how to decipher it, i got a little lost.

2.1-2.2 and 2.4, due on september 13

2.1 and 2.4 were pretty easy to understand, but the section in 2.2 about known plaintexts confused me. the math dealt a little with division in modular arithmetic, and i’m still a little shaky on that. i’m sure i’ll get it with time, but i just need to practice it.

when i was reading the sections about the simpler ways of encoding messages, it made me feel hopeful. i really feel like i’ll be able to be successful in this class! (i may be speaking too early) i’m relieved that the book is starting with extremely basic methods, and i’m excited to learn more complicated methods!

guest speaker on september 11 (due by september 13)

i actually really enjoyed listening to the speaker. i didn’t take any notes, and i can’t remember any specifics about the codes she talked about. but i thought it was all pretty interesting. i honestly had no idea that leaders of the Church used codes when they communicated. now that i think about it, it totally makes sense, especially for the early members/leaders. there was so much persecution they had to deal with, and they couldn’t risk giving away the identity of key people. i also really liked the code she was talking about at the end of class, the one with the code word and the 26 possible keys. it’s crazy that someone thought that up.

i honestly didn’t think anything was difficult to understand. i guess the most difficult part was that some of the codes were a little confusing, but i’m sure that whoever had to use them understood them well.

3.2 and 3.3, due on september 9

when i first read through it, the section on dividing and using fractions mod n kind of confused me. those are a little more complex than the basic mod n problems. i just wasn’t quite sure how exactly to do it, but i think that i will understand it if i practice doing it a little bit.

i remember when i first learned about modular arithmetic: i was so confused! but once i got the hang of it, i actually kind of liked it. i’m still not 100% comfortable with it, but i do enjoy doing some of the basic problems. it’s a pretty cool concept.

1.1-1.2 and 3.1, due on september 6

because 371 is still somewhat fresh in my mind, i think the most difficult stuff from this reading is all the new vocabulary. there are so many new terms and i keep getting them confused and forgetting. i’m sure they will come with time as we continually use them, but i need to keep reviewing them so i don’t keep confusing them.

i’m excited that the basic number theory from the reading is related to cryptography. i really enjoyed that section of 371 (probably because it actually made sense) and i feel pretty comfortable using it. it’s also so cool to think that there are some codes that are unbreakable! it actually kinda blows my mind when i think about how many possibilities and keys there are.

introduction, due on september 6

my name is tenery campbell. this is my 5th year at byu and my last semester of classes. i’m studying math education and will do my student teaching in the winter.
i did take calculus here at byu (twice—that’s how much i liked it), but i have also taken a lot of others:
math 113 (calc 2)
math 290
math 313
math 314
math 334
math 341 (bane of my existence)
and math 371.
i’m taking cryptography because for my major, it’s required that we take one of four higher upper-level classes (number theory, graph theory, combinatorics, or cryptography). i chose cryptography because it didn’t have the word “theory” in the title and it fit right into my schedule. also, it seemed like a really interesting class.
i don’t really have any experience with maple, mathematica, SAGE, or any other computer algebra system. i have done a little programming, but it was just programming on a graphing calculator. i do feel pretty comfortable using these programs, as long as i know how to use them. i’ll probably be just fine with it.
my favorite math teacher was one i had in high school for pre-calculus. he was my favorite because he was very realistic, and helped make math relevant. he made me want to learn more and i learned a lot from his class. not just about the subject, but about how to use a calculator and about life in general.
i have also had teachers who are on the other end of the spectrum. the least effective teacher i’ve had, at least for me, wasn’t very realistic. he was one of my math ed professors, and he always taught us about how we would teach ideally. not every situation is ideal, and we won’t be able to apply what he taught us every time we teach. i didn’t feel like he cared about what i had to say, because i had different opinions than he did.
in short, i feel like effective teachers need to be realistic and get on their students’ level. they need to help their students care about the subject and show them that it is relevant.
luckily, i have a weird name, so i don’t always have to make up something unique about myself. my name is tenery because i’m the tenth child in my family. (yes that really is true, and no the ninth one is not named ninery. and yes i’m the only one in my family with a number name.)