Project 5 Grades

[aruk...@asu.edu]

Hi, I was wondering why the average grade for Project 5 was so low compared to all the other projects? For example, I feel like we followed all the instructions well, but only received a 75. Were there any other grading criteria beyond what was explained on the project page or previously in the discussion board? 

Regards,

Adric Rukkila

[rssand...@gmail.com]

Hi Adric,

Most of people have not printed private key information correctly or have not printed at all. If you have any doubts regarding your marks, please come to our office hours.

The private key information should include modulus, private exponent, prime P, prime Q, prime exponent P, prime exponent Q and crt coefficient variables. Please follow java docs for more information about private key class. 

Regards,

Rubinder Singh

[aruk...@asu.edu]

Hi Rubinder,

The instructions just say "Print Raghu’s public and private key," nothing more. Which is to say, nothing about the modulus, private exponent, prime P, prime Q, prime exponent P, prime exponent Q, or crt coefficient variables. So we just printed the key itself. 

I understand how to derive such information from the key, but if more was required, why wasn't it specified? Especially if it was then part of the rubric?

Regards,

Adric Rukkila

[rssand...@gmail.com]

Hi Adric,

It is quite clear from statement "Print Raghu’s public and private key," that we are looking for information it is composed of and it is for purpose of students learning. So if you have not printed it, we cannot assume that you actually verified how public key and private key sit with each other before doing encryption decryption task.

Regards,

Rubinder Singh

[kai...@gmail.com]

I don't find that very clear at all. I think since there are so many lower grades for this project that most other people also found this unclear. 

[Partha Dasgupta]

1. "Print private key and public key" -- an RSA key consists of exponent and modulus. The modulus is public and there are two exponents (public and private). This was covered in class many many times. 

2. Other people got it wrong too -- that is not too relevant. Possibly other people did not know what keys meant. Your grade matters -- lower the average, the better for you.

3. Context and interpretation of questions matter. "What is 2+2?". The answer may be "4" or "arithmetic expression".

--p

Partha Dasgupta,
ASU/CIDSE/Computer Science & Eng. 
EMail: par...@asu.edu
http://cactus.eas.asu.edu/partha

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[aruk...@asu.edu]

Context is interesting, because we also say that "bits are bits" and "it's just numbers." So what is a key? It's just a number, stored somewhere. Knowing how that number was generated is essential to knowing RSA, but if you asked me, "What is your public key?" I'd send you the number in my RSA file, not n and e separately. 

I think this a difference between usages (how we send, receive, and read keys in every day life) and formal definitions (say, in rfc3447). I'd consider clarifying which interpretation you want in future assignments would be helpful.

Regards,

Adric Rukkila

--p

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[kai...@gmail.com]

I would agree. Please add clarification for the next semester of this class. It was an easy thing to print out and I am sad to have missed 25 points for something I *would* have done had I known it was expected.

[Partha Dasgupta]

The fist few lines of the RFC says:

   For the purposes of this document, an RSA public key consists of two
   components: 
      n        the RSA modulus, a positive integer
      e        the RSA public exponent, a positive integer

If you send someone your public key as some set of bits, how will the recipient know which is mod and which is exp -- these are important aspect of RSA encryption. So "print public key" means you print both numbers and identify what is what.

--p

Partha Dasgupta,
ASU/CIDSE/Computer Science & Eng. 
EMail: par...@asu.edu
http://cactus.eas.asu.edu/partha

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