What was difficult?
All the sections were very hard to read through. As the book mentions it is hard to explain quantum computing to a non-physicists. I wasn't able to follow most of the chapter and a lot of the time I felt like I was just reading words rather then understanding anything. As a computer science major it was too much for me to except that a computer can do a lot of the things that they said it can do. And when it got into the math of Fourier transforms I got further confused.
Reflections
While I was not able to understand the bulk of the section I was able to get a few things out of it. Quantum computing has been brought up before to me and I have never understood it. I was told that quantum computers can also sort numbers in O(n) which is also amazing. Advance in technology are always amazing and I would love to see the ideas of quantum computing materialized. In all the section was interesting in the ideas it presented, though a lot of the math went right over my head
Friday, June 6, 2008
Monday, June 2, 2008
Sections 4.5-4.8 and 8.7 due June 2
What was hard?
Section 4.5 was very hard to follow. I guess I am easily scared when I see a bunch of symbols and diagrams. I was unable to follow most of the subsections and have a very loose understanding of the section as a whole. I am hoping that I will gain a better understanding of it from lecture.
Reflections:
Section 4.8 (on password security) was very interesting. One of the first things I learned about computer security is passwords. I was always told to use a alphanumeric password and to use a different password for all my accounts. Doing so would make it hard for my account to be broken into as well as make it so if one account is compromised...not all accounts become so. I found it interesting that there are ways to help safeguard people who choose somewhat dubious passwords with the addition of "salt".
Section 4.5 was very hard to follow. I guess I am easily scared when I see a bunch of symbols and diagrams. I was unable to follow most of the subsections and have a very loose understanding of the section as a whole. I am hoping that I will gain a better understanding of it from lecture.
Reflections:
Section 4.8 (on password security) was very interesting. One of the first things I learned about computer security is passwords. I was always told to use a alphanumeric password and to use a different password for all my accounts. Doing so would make it hard for my account to be broken into as well as make it so if one account is compromised...not all accounts become so. I found it interesting that there are ways to help safeguard people who choose somewhat dubious passwords with the addition of "salt".
Friday, May 30, 2008
Sections 4.1, 4.2, and 4.4 due May 30th
What was difficult?
Following the DES algorithm was very hard and something I will definitely have to pay attention to in class. All the numbers and diagrams and steps caused a lot of confusion with me when I tried to understand the cryptosystem.
Reflections
One of the cool things about cryptography that this chapter mentioned was using one system to send a key for another system. It just seems weird and cool at the same time that two different systems are used in tandem to send encrypted data (though it makes total sense).
Following the DES algorithm was very hard and something I will definitely have to pay attention to in class. All the numbers and diagrams and steps caused a lot of confusion with me when I tried to understand the cryptosystem.
Reflections
One of the cool things about cryptography that this chapter mentioned was using one system to send a key for another system. It just seems weird and cool at the same time that two different systems are used in tandem to send encrypted data (though it makes total sense).
Wednesday, May 28, 2008
Sec 9.1 - 9.4 due May 28th
What was difficult?
Following the algorithms were not all that hard. However, it is not easy to see what a "digital signature" is without actually seeing how it effects the document. At first I thought it was a little encoding appended to the end of the document (however as the book mentions) this would make it easy for an Eve to copy and past it anywhere she pleases. This would mean that the digital signature totally changes the actual message. It was hard for me to understand how one could get the message back, or how multiple people could sign a message. However, I am sure after going over the algorithms in class I will understand it.
Reflections
One of the things that was interesting was the mentioning of using the Birthday Attack to get someone to sign the hash of one document that had exactly the same hash of another document. It was interesting to see that it suggests changing the document before signing it which inhibits the birthday attack from succeeding. It seemed weird that such an attack can be thwarted by merely changing one character before signing.
Following the algorithms were not all that hard. However, it is not easy to see what a "digital signature" is without actually seeing how it effects the document. At first I thought it was a little encoding appended to the end of the document (however as the book mentions) this would make it easy for an Eve to copy and past it anywhere she pleases. This would mean that the digital signature totally changes the actual message. It was hard for me to understand how one could get the message back, or how multiple people could sign a message. However, I am sure after going over the algorithms in class I will understand it.
Reflections
One of the things that was interesting was the mentioning of using the Birthday Attack to get someone to sign the hash of one document that had exactly the same hash of another document. It was interesting to see that it suggests changing the document before signing it which inhibits the birthday attack from succeeding. It seemed weird that such an attack can be thwarted by merely changing one character before signing.
Friday, May 23, 2008
Sec 8.3 due May 23rd
What was difficult?
Understanding how SHA-1 works at all was very hard. It was difficult to make sense of the algorithm. I kind of was able to follow the steps, but it was very difficult to make sense of it all. I was hard to see what the algorithm was trying to accomplish mainly because it is an iterative algorithm and unless you use an example as you go it is hard to see what exactly is going on at each step.
Reflections
It is strange how much work is needed to come up with a secure hashing algorithm. It was also interesting to see how many times "good" hash functions are found out to actually be insecure. I have heard of both SHA and MD before as they are used a lot in computers for verification purposes. I believe they are also used to read computer virus signatures which programs like norton and sophos use to identify viral files.
Understanding how SHA-1 works at all was very hard. It was difficult to make sense of the algorithm. I kind of was able to follow the steps, but it was very difficult to make sense of it all. I was hard to see what the algorithm was trying to accomplish mainly because it is an iterative algorithm and unless you use an example as you go it is hard to see what exactly is going on at each step.
Reflections
It is strange how much work is needed to come up with a secure hashing algorithm. It was also interesting to see how many times "good" hash functions are found out to actually be insecure. I have heard of both SHA and MD before as they are used a lot in computers for verification purposes. I believe they are also used to read computer virus signatures which programs like norton and sophos use to identify viral files.
Monday, May 19, 2008
Questions due May 19th
Which topics do you think are most important out of those we’ve covered since the last midterm?
I think the most important topic since the first midterm is factoring and hash maps. I think learning and knowing how to apply the factoring algorithms given to us to try to break cryptosystems is important. Also, the idea of hash maps and there various uses is also important.
What kinds of questions do you expect to see on the midterm?
I expect to see questions asking to factor a certain integer using x method. Of course being there are no calculators the integer would have to be small and the method used would have to be able to be executed in a small amount of steps. I also see questions along the line of "is this a good hash map". Also, I forsee definition questions.
If you were writing a question that would be appropriate for the midterm, what would it be?
Here is xyz hash map function, is it strongly collision free?
Solve 7^x = 12 (mod 41) using Pohlig-Hellman
I think the most important topic since the first midterm is factoring and hash maps. I think learning and knowing how to apply the factoring algorithms given to us to try to break cryptosystems is important. Also, the idea of hash maps and there various uses is also important.
What kinds of questions do you expect to see on the midterm?
I expect to see questions asking to factor a certain integer using x method. Of course being there are no calculators the integer would have to be small and the method used would have to be able to be executed in a small amount of steps. I also see questions along the line of "is this a good hash map". Also, I forsee definition questions.
If you were writing a question that would be appropriate for the midterm, what would it be?
Here is xyz hash map function, is it strongly collision free?
Solve 7^x = 12 (mod 41) using Pohlig-Hellman
Friday, May 16, 2008
Sec 8.4 due May 16
What was hard?
Understanding the logic and math behind the birthday paradox was a bit hard. Not because I didnt understand it, but because it just seemed untrue (I guess that is why its a paradox). I also looked it up online to further prove to myself its true. Also, I dont really see the use of the birthday paradox, as the book points out BSGS algorithm is still somewhat superior and it will work all the time.
Reflections:
Even though the book didnt really make clear how the birthday attack is used to successfully attack a system, it still is a cool idea. I hope to see cool examples in the future of using the birthday attack to break a system (with high probability). Also, was nice seeing probability used, some of the calculations reminded me of poison distributions (which is what I think they were using to calculate some of the probabilities).
Understanding the logic and math behind the birthday paradox was a bit hard. Not because I didnt understand it, but because it just seemed untrue (I guess that is why its a paradox). I also looked it up online to further prove to myself its true. Also, I dont really see the use of the birthday paradox, as the book points out BSGS algorithm is still somewhat superior and it will work all the time.
Reflections:
Even though the book didnt really make clear how the birthday attack is used to successfully attack a system, it still is a cool idea. I hope to see cool examples in the future of using the birthday attack to break a system (with high probability). Also, was nice seeing probability used, some of the calculations reminded me of poison distributions (which is what I think they were using to calculate some of the probabilities).
Subscribe to:
Posts (Atom)