Category Archives: Ciphers

This one is entirely graphical: Thanks go to James Aaronson for the design.

After an important and immersive conversation lasting no fewer than four hours, I had very little time to compile this particular cipher. Its appearance reminded me of the endoplasmic reticulum surrounding the nuclei of biological cells, hence the name. I would … Continue reading →

At the moment, assuming everything has gone according to plan, I should currently be on a northward-bound train, returning from Kevin Buzzard’s talk at the Royal Society. As with some of the earlier ciphers, this is bipartite, consisting of both an image … Continue reading →

+39256408486145507991522778312122523892525408578736546 Sorry about the cryptic title and lack of hints.

Occasionally, some of my ciphers have the frustrating property that whilst easy to realise what to do, they can still be incredibly long-winded to solve. I can imagine that this is one such cipher: I apologise for the profusion of Petersen … Continue reading →

This is classically used as a rudimentary compression algorithm, although it also makes for a nice cipher challenge. 000011010110111 0100001111000111 1110 11000011100111101101001 001011101010100111 110100101 01001110100111110001010110001110111101111011010, 001001110101101001101010 11100111 1110 01100100000101001010011111101010 0000101100100, 0011001101011010010110 01011001100010101100011110010100000111 1111010000000010001010111 0011010110000110 01001110111111110110100111 110100101 001000111001011011111011000011110100 1111010010101100110000110 111111001100011001010111111001010000 11011010 … Continue reading →

For this cipher, I have encoded the information in a list of real numbers. Ordinarily, these would be complex, but I managed to circumvent this. Unfortunately, the ciphertext is thus longer than it needs to be. Really, it’s twice as … Continue reading →

This can be regarded as a sequel to cipher 21. One of the problems with that cipher was the fact that people could cheat by using an online Sudoku solver; I don’t believe that this suffers from the same vulnerability. … Continue reading →

I’ve incorporated a few classical ciphers before, but generally avoided the Caesar cipher due to how trivial it is to brute-force. This one should present more difficulty: When you have the password, use it to access the protected area.

Occasionally, mathematical olympiads contain no classical Euclidean geometry. One such example is the IMO paper in the action thriller X+Y, which encompasses discrete combinatorics, additive combinatorics and algebra. To compensate for this, I have designed a cipher based entirely on Euclidean plane … Continue reading →