COSI 171a Assignments

All assignments should be submitted on paper, so that the TA's can conveniently provide feedback.

• Programming assignment source code should be submitted also to cs171a as Email enclosures.
  
• The subject line should read "HWn", where n is the number of the assignment.
  
• Source code should be packed and zipped to preserve the directory structure of its contents.
  
• Standard libraries (stdio.h, math.h etc.) should not be enclosed, only your own files.
  
• All source code must be well documented. On a trial basis, we will now accept perl and python.

Assignments are due BEFORE class begins; late arrivals lose credit.

• Assignment 1, Friday, 30 August 2004
  • Due Friday, 3 September 2004
    Read Section 1.1
  • Due Friday, 10 September
    
    1. Read Sections 1.2, 1.3
       
    2. Program the shift cipher and the Viginere cipher for English. Your programs should first delete spaces,
       numerals, and punctuation, and should change all characters to upper case.
       
    3. Program a binary stream cipher, using LFSR's (linear feedback shift registers.)
       A list of (some) primitive polynomials for LFSR's is among the links on the homepage.
       This binary stream cipher is NOT secure, but will quickly scramble your files to confound your roommates and relatives.
    The programs should take the key as a command-line argument; input files can be command-line arguments or redirections.
  Solutions (text)
   
• Assignment 2, Friday 10 September 2004
  • Due Tuesday, 14 September 2004
    Read Sections 2.1, 2.2, 2.3, 2.4.
  • Due Tuesday, 21 September 2004
    Using your programs, do Exercises 1.21, 1.29.
    To save you the labor of transcription, here are the ciphertexts.
    Solutions
    
   
• Assignment 3, Tuesday, 21 September 2004
  • Due Friday, 24 September 2004
    Read Sections 3.1, 3.2, 3.5, 3.6; don't memorize them!
  • Due Tuesday, 28 September 2004
    Do Exercises 3.2, 3.3. Read Exercises 3.4 and 3.8; we will discuss them in class.
    Show that a one-round DES encryption plus a left/right swap is self decrypting.
    Solutions
    
   
• Assignment 4, Tuesday, 28 September 2004
  • Due Friday, 1 October 2004
    Read the Rivest article listed under "Useful Links"
  • Tuesday, 28 September 2004
    Quiz in class. Solutions
    
   
• Assignment 5, Tuesday, 5 October 2004
  • Due Friday, 8 October 2004
    Read Sections 4.0, 4.1, 4.2
  • Due Tuesday, 12 October 2004
    Stinson 4.1 (TYPO: "2N" should be "2S"), 4.2, 4.5. Solutions
    Extra credit: In the Birthday Paradox, find the expected number of people to achieve the first collision.
    What's known.
    
   
• Assignment 6, Tuesday, 12 October 2004
  • Due Friday, 15 October 2004
    Read Sections 5.1, 5.2, 5.3
  • Due Tuesday, 19 October 2004
    Do Stinson 5.1; read 5.2, it was done in class; 5.3, 5.4, 5.5, 5.6 (using your programs); 5.8
   
• Assignment 7, Tuesday, 19 October 2004
  • Due Friday, 22 October 2004
    Read Sections 5.4, 5.5; read Schneier's blog on DES
    
  • Due Tuesday, 26 October 2004
    Read Stinson 5.6
    Do Stinson Exercises 5.9, 5.10, 5.11, 5.13. Solutions.
    
   
• Assignment 8, Friday, 29 October 2004
  • Due Tuesday, 2 November 2004
    Read Sections 5.7, 5.9
  • Due Friday, 5 November 2004
    Do Stinson Exercises 5.14, 5.15, 5.16, 5.17, 5.18;
    Read Exercise 5.22, completing the proof of Solvay-Strassen's efficiency. Solutions
    
  • A quiz is planned for 9 November: Solutions
    Statistics will be published when my spreadsheet is fixed.
    
   
• Assignment 9, Friday, 5 November 2004
  • Due Friday, 12 November 2004
    Read Stinson Section 6.1, 6.2.1, 6.2.2, 6.2.3
    Do Exercises 6.1, 6.2 without the proof.
    
   
• Assignment 10, Friday, 12 November 2004
  • Due Friday, 19 November 2004
    Read Stinson Section 6.6, 6.7
    Do Exercises 6.3, 6.4 except for part d.
    Solutions
    
   
• Assignment 11, Friday, 19 November 2004
  • Due Tuesday, 23 November 2004
    Read pages 397 to 394 in the handout from Stinson First Edition.
   
• Assignment 12, Friday, 3 December 2004
  • Due Friday, 10 December 2004
    Do Exercises 13.1, 13.2 in the handout from Stinson First Edition.
  The final exam takes place Tuesday, 14 December. It will be two hours long,
  with one-half hour dedicated to questions from previous exams.
  Watch this space for Solutions.ps