Codebusters

Q: Are xenocrypts only limited to Spanish? The wording makes it unclear. (Section: 3 / Paragraph: e / Line: 7)

A: Yes. For this year, all Xenocrypts will be in Spanish.

Q: For aristocrats with spelling/grammar errors, should the errors be included in the final answer? (Section: 3 / Paragraph: e / Sub-Paragraph: iii / Line: 5)

A: Yes. The final answer should exactly match the errors in the encoded text. Specifically if the aristocrat was LFOE JG KOI GNFQJH then the correct answer would be HEAR IS BAD SPELIN in order to count as zero mistakes.

Q:  Is xenocrypt necessarily monoalphabetic substitution? (Section: 3 / Paragraph: e / Sub-Paragraph: vii / Line: 1)

A: Yes. All Xenocrypts will be mono-alphabet substitution following the same substitution rules of Aristocrats.

Q: What type of baconian Cipher is being tested, the one in which V and J do not have a unique code or the one where all the letters have a unique code? (Section: 3 / Paragraph: e / Sub-Paragraph: vi / Line: 1)

A: The Baconian ciphers will use the 24 character alphabet in which I and J are both represented by ABAAA and U and V are both represented by BAABB.

Q: Will the crib necessarily be provided in the exam? (Section: 3 / Paragraph: f / Sub-Paragraph: iii / Line: 1)

A: Not for all questions. "cribs" (also known as Hints) will only be supplied for cipher types under rules 3.e.iii.(1), 3.e.iii.(3), 3.e.iii.(5), 3.e.vi, 3.e.vii, 3.f.iii and 3.f.vi.

Q:  Does "Mathematical Cryptanalysis of the Affine Cipher" refer to merely decoding a cipher given the a and b values, or determining the a and b values from given ciphertext? (Section: 3 / Paragraph: f / Sub-Paragraph: vii / Line: 1)

A: Mathematical Cryptanalysis of the Affine Cipher means that the student has to decode the entire plain text of the cipher given two plain text characters to match the cipher text.

Q:  For monoalphabetic ciphers, is an error defined as per incorrect letter or does one error encompass everything from that letter matching to an incorrect letter? If A is B and if the word AA is translated by mistake to CC is that 1 or 2 errors?. (Section: 4 / Line: 1)

A: Errors are counted against the decode phrase and not the alphabet. If A is supposed to map to B, then AA mistakenly translated to CC would count as two errors.

Q:  Must competitors finish the first question before moving on in order to obtain points for the bonus, or may one or two students move on from the first question while others work on the first question in the first 10 minutes? (Section: 3 / Paragraph: d / Line: 1)

A: Rule 3.d states that "participants are free to answer the questions in any order, working individually or in groups, attempting whichever of the questions seem right for them." Therefore, there is no requirement to complete question 1 before moving on to the other questions to be eligible for the timing bonus on the timed question.

Q:  Are different types ( i.e. pencils, highlighter, pens, etc.) of "writing utensils" acceptable? (Section: 2 / Paragraph: a / Line: 1)

A: Yes. pencils, highlighters and pens are all valid writing instruments. However, any solutions written must be readily read by the person grading the test and an answer written only with a yellow or other color highlighter may be scored the same as a non-answered question.