Final release of p2 spec


Hey folks. Thanks Aditi for suggesting that I add a sentence about the file format required for messages and pads. I’m now considering this the final draft; enjoy!


Project 2 specification


8 Responses to “Final release of p2 spec”

  1. Kelsey Francis Says:


    Will our programs be judged on memory usage, or just execution time?


  2. diabolicalmdog Says:

    I wouldn’t count off for memory usage unless it made our system crash; so I’d say if you keep your memory usage sane you’ll be fine.

  3. Kelsey Francis Says:

    I have another question. Will the computer(s) our code is tested on have multiple cores? If yes, could we get a hint about how many?

  4. diabolicalmdog Says:

    You can assume multiple cores (say 4)

  5. diabolicalmdog Says:

    Something that came up with a student: The rotation of multiple pads will be “round robin,” which implies that the pads you output should have some kind of order to them. You can assume that the cypher “starts over” with the first pad when it’s newly invoked, but that when its fed multiple files from the command line that it starts from the first pad and rotates through them. So, when you recover pads, you need to make sure they are in the proper order (i.e., create filenames that are sequential). Hope this clears things up.

    • Kelsey Francis Says:

      So since the recover command takes in a directory as a parameter, can we just sort all the files in that directory lexicographically and safely assume that that was the order in which they were encrypted and can be decrypted?

      • diabolicalmdog Says:

        For the files being read from the directory, you should read them in the order that they’re listed (the order of the results from ls / readdir / etc.). It’d make sense to name the files in the directory sequentially 00000001.x, 00000002.x, 00000003.x, etc.

  6. diabolicalmdog Says:

    Regarding grading, I haven’t written out an exact rubric yet, but it’s fair to say that between 25 and 50% of the grade will come from one-time pad recovery, with some opportunity for credit for just the single one-time pad case. The rest of the grade will come from basic functionality, documentation, etc.

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