ScioVirtual

General Tips for Decryption:

Factorization is key!! The first step to a CCT cipher is to count the number of characters, and then figure out how many columns there could be. NOTE: minimum number of columns is 3X marks the spot. In a CCT cipher, let’s say you use a quote of 82 characters encoded using 7 columns. Well, you need 84 characters to create 7 columns of 84 / 7 = 12 letters each. So how do you get there? Add 2 X’s at the end of the quote - when decoding you simply ignore them when writing out the decrypted message.

CLARIFICATION: when you encode a message, you put the 1st letter in Column 1, 2nd letter in column 2, 3rd letter in column 3, etc. Once you reach the end of a column you wrap around to column 1. After you create the columns, you make the ciphertext by placing column 1 in order, then column 2, etc. So the X’s end up being a whole column length away, or a multiple of it.Look for the letters in the crib keyword given (quote contains “__”). If the letter ends up being very uncommon then it’s very easy to track the potential number of columns it could be. Work your way down. Start with the most amount of columns possible and then go down to the lower cases. According to the official rules, the length of the crib of the plaintext given must be no shorter than one less than the number of columns used. So if the crib was “there,” then there cannot be 7 or more columns, so you can also rule out those possibilities (or ask the event supervisor to discount the question.)

Let’s try some example problems! These will be regional level so no more than 9 columns :)

EXAMPLE 1

Solution 1

We can count that there are 70 characters in the quote. The factor pairs of 70 are (1, 70), (2, 35), (5, 14), and (7, 10). Using these pairs we can surmise that there are 5 or 7 columns. Now let’s look at the X’s in the quote. We see one at position 10 (positions 1-70 are used as opposed to 0-69), another at position 30, and another at position 40. The first two are separated by 30 - 10 = 20 characters while the second two are separated by 40 - 30 = 10 characters. So it looks like each column has 10 characters - this means there are 70 / 10 = 7 columns.Rearranging this into these 7 columns gives us:

We can see that in the 4th row there are 5 letters of baseball (A, L, L, B, E) and that in the row above there are the other 3 letters of baseball (B, A, S). But there are multiple A’s in the third and fourth rows. So how do we figure out what order they are in?Look at the end of each column. We can see in columns 1, 3, and 5 that there are X’s at the end - so these must be on the right. Clearly to get B, A, S, we organize them like this:

Then it becomes clear how to organize the first 4 columns (the last 3 are set due to the X’s at the end (BAS (3rd row) + EBAL + L (column 5):

ANSWER: If you have a bad day in baseball and start thinking about it, you will have ten more.

EXAMPLE 2

Solution 2

We can count that there are 84 characters total in the quote → meaning we can have 3, 4, 6, or 7 columns. We also can see an X at position 70, which we’ll assume is the end of some number of columns. Since it is at position 70, that means there are 14 letters after it. So the number of letters per column is a factor of 14 (since 14 and 70 share a factor of 14). Doing a quick check, we can see that 84 / 1 = 84 columns is absurd, 84 / 2 = 42 columns is not valid, and the same can be said about 84 / 7 = 12 columns. So there must be 84 / 14 = 6 columns.Arranging this gives us:

We can see 5 letters of “saying” in row 6 and the ending G in row 7. So it must be organized as SAYIN → G___ (This makes sense too, since the N should be at the end since it contains the X.) *The arrow denotes moving down from one row to another.

Thus we get: