Make-up work must be completed as soon as possible after an absence. I will not accept a pile of make-up work coming in on the last day or two of class. In any case, all class work must be turned in by Friday, January 26, before I leave campus.

• W 1/3
  • Sinkov #1-8
  • Lab 1
• R 1/4
  • Sinkov #9, 11-14, 16, 23
  • Lab 2
• M 1/8
  • Do Lab 4 while reading Sinkov pp. 47-55.
  • Sinkov #32: Prepare trigraph frequency distribution and solve the cryptogram.
• T 1/9
  Exam 1
• R 1/11
  • Sinkov #43, 44, 46
    Show your supporting work.
  • Lab 6
• F 1/12
  • Summarize the evidence for the keyword length of the cryptogram on page 79 of Sinkov.
  • On pp. 87-88 Sinkov compares 1:2, 2:3, 3:4, 4:5. Use the Lab 7 prodedures to do the other six comparisons (1:3, 1:4, 1:5, 2:4, 2:5, 3:5) and assess what alignment of alphabets works best.
  • Sinkov #48, 49, 50
  • Lab 7
• M 1/15
  Exam 2
• T 1/16
  • Who published the earliest known digraphic system?
  • Who devised the Playfair cipher?
  • Using a Playfair square based on the keyword "PALMERSTON," (a) encipher "call home at once" and (b) decipher ZGGLSTSLTG.
  • Using a Playfair square based on the keyword "GUSTAV," decipher HSTAT GBVUN EQCA.
  • Use the linear transformations C₁ = 2 P₁ + 3 P₂ (mod 26) and C₂ = 5 P₁ + 6 P₂ (mod 26) to encipher "Hello, world!"
  • Use the linear transformations P₁ = 24 C₁ + C₂ (mod 26) and P₂ = 19 C₁ + 8 C₂ (mod 26) to decipher ERHBU EFAJF
  • Sinkov exercise 64
  • Lab 8
• W 1/17
  • Sinkov exercises #65, 66, 67
  • Sinkov exercises 69, 70
  • Study Sinkov pp. 130-139.
    Assuming that the cryptogram was enciphered by Hill's digraphic cipher, figure out what the following digraph equivalences tell us about the entries in the deciphering matrix:
    • XZ = th
    • KY = e? and AN = e?
      Here ? stands for an unknown letter, possibly different in each case.
• R 1/18
  • View the Nova video "Decoding Nazi Secrets" and write a summary.
  • Describe the extended Euclidean algorithm; use it to solve the following problem:
    • g = gcd(234, 432) = ?
    • Find integers s and t such that 234s+432t=g.
    • Solve 234 x = 54 (mod 432) for all solutions.
• F 1/19
  • Use the extended Euclidean algorithm to find the greatest common divisor g of 851 and 703 and integers s and t such that 851s + 703t = g; then find all solutions of 703 x = 74 (mod 851).
  • Describe the RSA algorithm using the same notation as in class, and illustrate the encipherment and decipherment of "yes" using the RSA encipherment based on primes p = 11 and q = 31.
  • Lab 9.
• M 1/22
  Exam 3
• T 1/23
  • Solve the Exam 3 problems.
  • Encipher "Civil War field cipher" via a railfence cipher with key 213.
  • Sinkov Exercises 74-75
  • Solve the following complete columnar transpostions (show your work):
    • MERTS SIAHS GOHSS EIT
    • HEORF LSCTW IPORL OARCN EHOSE SLNDS LHYPT MLXIV TAAHW URTEO NTNOL EEEVX AGLYN RGESF SXHTO TNFEO AITSO HMSIE
• W 1/24
  Solve the following incomplete columnar transpositions, showing your work:
  • TSOSA TRPYU ARMEI OWARA AONSG AREHC NMTES SNABD HTSSI YIATP LTEAT ENECN BOTYL YGT
    Probable word: "probable"
  • IPLAI HLTCH EFAOH ORWKR ACTIT AMLNO NPTRO DCEMO RTTBE LEXAR SABDI AEMSN PWOAS LUNOE EHR
    Probable words: "the probable"
  • GAELT CCRNT EOMEL EDOND GSBDH SOEDU HDAEE EEINT TEEAQ UENES EGGTO EGPHI NNUUL SANEB YEAHM IESNA RLBBV DE
• R 1/25
  For each presenter note
  • the presenter's name
  • the title of the talk/paper
  • the main results of the presenter's research
• F 1/26
  For each presenter note
  • the presenter's name
  • the title of the talk/paper
  • the main results of the presenter's research