NumberWorld

There are some arguments that the Dorabella Cipher is actually not a real cipher, which are based on the existence of long strings of consecutive symbols with pair-wise different number of semi-circles. Using theory and practise i will show that this is actually not as suspicious as it may seem but it indeed maybe a hint that something is fishy. T here’s an argument that the Dorabella Cipher may not be a real cipher at all. The main reason given is that it contains long stretches where the number of semicircles alternates: adjacent symbols never have the same semicircle-count. In this post I’ll test whether that pattern is actually as suspicious as it sounds.The Dorabella Cipher has remained unsolved for about 130 years. While looking for recent discussion and solution attempts, I went well beyond the first page of Google results and found several excellent deep-dive blogs. One post on ...

The Zodiac ciphers occupy a unique place in the history of cryptography because they are not abstract puzzles or literary inventions. They are directly connected to a real series of murders committed in Northern California in the late 1960s. The anonymous sender, who called himself the Zodiac, mailed several encrypted messages to newspapers, using the ciphers both to taunt the public and to assert responsibility for the killings. Unlike most historical ciphers, these messages were part of an active criminal investigation. Their successful or unsuccessful decryption had immediate consequences: it influenced public fear, police strategy, and media coverage. For this reason, the Zodiac ciphers are studied not only as cryptographic artifacts, but also as documents situated at the intersection of mathematics, psychology, and criminal history.

LCS35 IS SOLVED. It had been confirmed that Bernard Fabrot solved the challenge using a Core i7-6700, the GNU Multiple Precision Arithmetic Library and 3,5 years of time. The LCS35 challenge (see also Scienceblogs ) is a neat little and still unsolved challenge posed by Ron Rivest, one of the inventors of the famous RSA cryptosystem, back in the year 1999. It consists of a single task: Given 2048-bit RSA integer $n$ and an exponent $t$, compute the following value $W$: $$W \equiv 2^{(2^t)}  \pmod{N}$$ The actual values for the challenge are: n = 631446608307288889379935712613129233236329881833084137558899     077270195712892488554730844605575320651361834662884894808866     350036848039658817136198766052189726781016228055747539383830     826175971321892666861177695452639157012069093997368008972127     446466642331918780683055206795125307008202024124623398241073     775370512734449416950118097524189066796385875485631980550...

I don't know why, but in the last days I used my spare time to think about the good old D'Agapeyeff Cipher . As a reminder, below you see the actual ciphertext like it is presented in his book: 75628 28591 62916 48164 91748 58464 74748 28483 81638 18174 74826 26475 83828 49175 74658 37575 75936 36565 81638 17585 75756 46282 92857 46382 75748 38165 81848 56485 64858 56382 72628 36281 81728 16463 75828 16483 63828 58163 63630 47481 91918 46385 84656 48565 62946 26285 91859 17491 72756 46575 71658 36264 74818 28462 82649 18193 65626 48484 91838 57491 81657 27483 83858 28364 62726 26562 83759 27263 82827 27283 82858 47582 81837 28462 82837 58164 75748 58162 92000 Remark: In the first post, i wrote that the puzzle only appeared in the 1939 version of the book but meanwhile i got new information. The puzzle is still contained in the reprinted version from 1949. The first version that comes without the puzzle is the vers...

Heureka , the cryptogram that was published in 2007 by Klaus Schmeh [ 1 ] was finally solved on 26.11.2013 by George Lasry .  MysterieTwister  (user: george4096) made today the official announcement about his achievement.

Ok, let us shortly recall what we know: As far as I know, all existing images of the Dorabella cipher do not show Elgar's original message, but Penny's rewritten version, which she published in her memoirs. Perhaps this act of rewriting removed some information that might have been helpful. For example: the orientation of the symbols; the length of the lines; since a horizontally reversed symbol is also a valid symbol, perhaps she wrote everything upside down; sometimes the cipher symbols are ambiguous, did she get the right direction of each symbol? etc... Elgar used his cipher symbols at least four times: Lisz-Fragment, Courage Card set, Dorabella cipher, notebook. The suggested solution(s) for each of these parts do not fit together, i.e., a solutions for the Lisz fragment can not directly be applied to the, e.g., dorabella cipher.  This either means that those solutions are wrong, or that Elgar slightly varies his system each time, or that Elgar just uses his symbols a...

Today, only a very small update regarding the Dorabella cipher. Below is a timeline showing the 4 points in time when Elgar used his cipher symbols. If anyone knows of another point and can tell me what Elgar did with his symbols or what he wrote about them, please let me know. Timeline: 1 - - - - - - - - - - 2 3 - - - - - - - - - - - - - - - - - - - - - - 4 1: 1885/86 - That is the Lisz-Fragment; the annotation he wrote on the side of some musical nodes [Figure 5,6, in Part 1 ]. 2: 1896 - The Courage card set. He wrote his cipher symbols [Figure 3, in Part 2 ] on the first card of the set of nine cards on which he explained his solution of the Pall Mall Magazin cipher challenge. 3: 1897 - The Dorabella cipher [Figure 1, in Part 1 ]. 4: 1920 - His notebook, that contains the example subsitutions [Figure 2, in Part 1 ]. Based on this timeline, one can see, that the timespan between $3$ and $4$ is $23$ years. Thus the cipher scheme approach written in h...

The 1939 edition of D'Agapeyeff's book Alexander D'Agapeyeff was a Russian-born cartographer who lived most of his life in London. He became famous for his exercise cipher, he left for the readers on the last page of the first edition of his book "Codes and Ciphers" published in 1939. In the later revisions of his book, he removed this exercise. The reason, he said, was that he had forgotten how he did the encryption. Perhaps he has not really forgotten how to do it, but he has made some mistakes that prevent him and everyone else from deciphering the message. What makes me a little angry is that he did not reveal what he remembered. He probably still knew what method he was supposed to have used and some of the words that were in the message. Just as he knew that many people were working on a solution, why did he not support them with a little information? The D'Agapeyeff cipher is one of those ci...

Elgar seems to have been so familiar with his cipherbet, that he even was able to quickly write some notes or annotations. Which means, that he either learned this cipherbet by heart or he could quickly deduce the corresponding cipher symbol from a given letter. And if so, why shouldn't it be possible that he quickly writes to Penny the more or less irrelevant note   "P.S. Now drocp beige weeds set in it – bure idiocy – one endtire bed! Luigi Ccibunud lu'ngly tuned liuto studo two." or reinterpreted  "P.S. Now droop beige weeds set in it - pure idiocy - one entire bed! Luigi Ccibunud luv ' ngly tuned liuto studo two." as Tim Roberts solution suggests? In Figure 1 one can the three Pigpen circles for his solution. Figure 1. The Pigpen circles for T. Roberts solution. The red marked letters indicate symbols that are not used in the Dorabella cipher. Of course, he did not use this representation but used the key setence " LADY P...

Today we explore one of the most famous unsolved cryptographic mysteries in history — the Dorabella Cipher, a coded note written in 1897 by the English composer Edward Elgar to his friend Dora Penny. Even after more than a century of attempts by expert cryptanalysts, its meaning remains a genuine enigma that still captures the imagination of mathematicians, historians, and puzzle lovers alike. What makes this cipher exceptionally fascinating is not just that it’s unsolved — but the unusual context in which it was created. Elgar, already a gifted composer (best known for works such as the Enigma Variations), crafted a string of strange semi-circular symbols addressed to a woman with no particular background in ciphers or codebreaking. Why would a composer write a secret message that no one — not even its intended recipient — could decipher?  Below, in Figure 1, you can see the famous  Dorabella Cipher , which Edward Elgar wrote to Miss Dora Penny 1897. Figure 1. The Dor...