The first reason of the Great Cipher used was remained unbroken for 200 years is that the creative idea of replacing syllabus by different numbers. With the development of the cryptography, more and more encrypting methods are invented. This limits the thoughts of people to use previous methods to solve this new encrypted method. Also, it limits people that different alphabets are related to different numbers. It is hard for someone to come up with the idea that the numbers are representing the syllabuses of words. The second reason is that the amount of work is huge and difficult to analyze. With 587 different numbers, trying only one method without making any mistakes during the process itself is difficult to finish. For Bazeries, it takes him three years to finish decrypting the message and he is brave to try the idea of using numbers to represent the syllabus. An attempt to decrypt the method is already time-consuming and boring. Someone may have come up with the same idea with Bazeries, but the difficulty of finishing it held him back. He may mentally tell himself that this idea is impossible since no one has used that before. This thought provides him comfort for not trying the method at all. What’s more, the amount of the work requires people to be patient. Once, people get angry or bored about the decryption; he is more likely to make more mistakes. All these reasons makes the information as a secret for 200 years.
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The Great Cipher of King Louis XIV was an enhanced monoalphabetic substitution cipher that managed to remain unsolved for over two centuries. It was developed by the father-and-son team of Antoine and Bonaventure Rossignol, two of the best cryptanalysts in France. King Louis XIV used it to securely encrypt sensitive information regarding his political plans. The first characteristic of the Great Cipher that made it so strong was that it used 587 different numbers to encode messages rather than just 26 symbols, like a standard monoalphabetic substitution cipher. This meant that there were multiple possibilities for the significance of each number. Cryptanalysts initially thought that each number corresponded to a single letter, with several ways to represent each letter. A cipher like this would be quite effective in that it would be immune to frequency analysis, but the Great Cipher was actually even more complicated. Rather than a single letter, each number represented a full syllable in the French language. Since there are so many possible syllables, this method is several times more secure, requiring a cryptanalyst to match up far more than just 26 pairs of meanings. In addition, the Rossignols made the cipher extra deceiving to potential codebreakers by making some of the numbers delete the previous syllable instead of signifying a unique one. All of these strong encryption techniques contributed to the longevity of the Great Cipher, and it remained unsolved until expert cryptanalyst Commandant Étienne Bazeries finally broke through 200 years later.
The Great Cipher used by Louis XIV encoded syllables and single letters using 587 different numbers and remained unbroken for 200 years. One factor contributing to the strength of this cipher could be that during the time period in which the cipher was in use, the most well known ciphers included the monoalphabetic substitution cipher, the polyalphabetic substitution cipher, and the homophonic substitution cipher. People had commonly being encoding their message one letter at a time. Consequently, many trying to break The Great Cipher may have not considered syllables, consisting of a varying series of letters, were being encoded as one number. To further increase the strength the cipher, some single letters did correspond to a single number which would further confuse the cryptanalyst as to which numbers represented single letters and which represented syllables. To add to the confusion there were numbers that were traps which did not represent a syllable or a letter. Trap numbers deleted the previous number in the ciphertext. This cipher incorporated three layers of complexity which could attribute to why it remain unbroken for two centuries.
Furthermore, Louis XIV’s plaintext was in French meaning that enemies who potentially intercepted the messages would be unlikely to known common French syllables unless they were literate in French. It was probably more likely for a French-speaking people to loyal to his or her king than to Spain or other enemy countries during Louis XIV’s reign.
Lastly, after some time passed after Louis XIV’s reign the group of people interested in decoding his secret messages shifted from enemies to historians. Historians acknowledged the value of decoding the king’s secret messages to gain insight regarding the 17th century however, the urgency was nowhere near that of the enemies. Enemies need to decode his messages of his political scheming and planned attacks within days for the information to be of any benefit to them. A century later, the details of the dead king’s plans did not need to be deciphered within days considering they were events of the past. The lack urgency may have also contributed to the long lasting unbreakability of the cipher.
Louis XIV’s Great Cipher was unique in its complexity, far far beyond the other ciphers used during the time period. Indeed at the time, by far the most popular type of cipher was the mono alphabetic substitution cipher, yet that is easily deciphered by a good cryptanalyst through the use of frequency analysis. The Great Cipher was much more than a simple mono alphabetic substitution cipher in that it utilized numbers to represent letters, but on top of this, the numbers didn’t just stand for letters they also stood for syallables. Since there was not a 1 to 1 relationship between letters and the cipher alphabet, it was nearly impossible to perform traditional frequency analysis on the cipher text. Furthermore, the cipher was brilliantly created with cipher text indicating to ignore the previous syllable or letter, making it tricky for any decoder to figure out what was part of the cipher and what was simply nonsense.
Perhaps the deciphering of the Great Cipher is even more impressive than the creation of such a complex cipher. The amazing creativity and brilliant thinking that Bazeries had to even consider looking at syllables has to be commended. Furthermore, for him to harp on a repeated phrase and be able to figure out what it meant is incredibly impressive. This also illustrates how amazing the cipher was in that it took Bazeries over three ears to crack it even with his uncanny ability to recognize that it is comprised of syllables.
The first thing The Great Cipher used by Louis XIV did well was not being a monoalphabetic cipher. These ciphers are too susceptible to frequency analysis, making them crackable in a matter of hours at the most. Instead, the Great Cipher is more along the lines of a polyalphabetic cipher. Instead of letters, however, the cipher alphabets are compromised of numbers. But the thing that really makes this cipher a strong one is the fact that these numbers represent single syllables, letters, or even commands instead of just single letters. In doing this, deciphering The Great Cipher would take years.
This cipher took 200 years to decipher due to the odd nature of the cipher. No conventional ciphers substituted numbers for both syllables and letters, as well as having some traps lain within. Due to this, nobody knew how to begin deciphering it. It was only through the efforts of Bazeries that this cipher was eventually cracked. Even so, it took Bazeries 3 whole years to figure out the messages hidden behind the code. He was only able to crack the code as a result of his very out of the box thinking and pure determination. After trying polyalphabetic combinations, which are hard enough to crack on their own due to the pure number of possibilities that exist, and diagraphs, which also took a long time, Bazeries thought to try syllables. It was only after trying many different combinations that he found a single phrase which worked. He then used this word to painstakingly decipher the rest of the text. The pure creativeness of The Great Cipher led to its strength, and the only way it could be decoded was through equal creativity.
I see The Great Cipher is synonymous to the simple monoalphabetic substitution cipher, just on steroids. The concept is the same—one cipher letter or multiple cipher numbers represent a number of plaintext letters. However, what makes the two so different in their difficulty to be cracked lies in the sheer possibility of combinations that could be created from each cipher.
The cipher key was not limited to just one letter replacing another; instead, a few numbers represented syllables. Thus, this opened up a lot more possibilities to stump cryptanalysts.
Before, it was clear in monoalphabetic substitutions that one cipher letter represented one letter of the plaintext. Therefore, we were only faced with a certain amount of different cipher keys to deal with. Even though a completely random monoalphabetic cipher would yield so many possibilities, frequency analysis could easily help decipher it. But now with a cipher with undeterminable characteristics (does “1” represent a letter or does “123” represent one letter? Or a syllable? I’m guessing they did not know how many numbers represented how many letters), patterns that lead to the cracking The Great Cipher become less obvious. There is a multitude of syllables that exist in the French language, making combinations all the greater in amount. This increases the difficulty because although we might see a string of numbers or other patterns, the specific plaintext it refers to—whether it be just one letter or two or three—has much more holes and traps.
In addition, many people might still be familiar with only the mono alphabetic substitution (since cryptology was still developing), so people might have not thought in a “numbers now represents syllables” way just yet. A reason for the people’s unfamiliarity would be that since the Great Cipher was made by two people (the Rossignols) who already knew how to crack extremely hard ciphers, their knowledge of the weakness of strong ciphers bolstered their knowledge to build something knew that didn’t fall into the traps of the simple mono alphabetic substitution cipher. As such, because they thought five steps ahead of everyone else. In addition to their death, the Great Cipher remained unsolved for 200 years because the only people smart enough to crack hard ciphers and used the weakness of those to create a new super hard to crack cipher had died. In short, their knowledge of the Great Cipher died along with them until it was unearthed 200 years later.
The father-and-son team of Antoine and Bonaventure Rossignol invented the Great Cipher for the French king Louis XIV to encrypt the empire’s most secret messages, protecting details of his plans, plots and political schemings. While the nature of the Great Cipher was simply an enhanced monoalphabetic cipher with homophones, it seemed implausible that it remained unbreakable for two centuries. However, there were two main factors that led to such a secure cipher.
The most significant one was considered to be the Rossignol’s ingenuity and resourcefulness. Including 587 different numbers, the Great Cipher was obviously not a straightforward substitution cipher. But when Étienne Bazeries, a distinguished cryptanalyst tried to crack it as a homophonic cipher, he failed. He then came up with the idea that each number might represent a digraph, or a pair of letters. Although his efforts to this deciphering approach again yielded nothing, it enlightened him on the possibility that some numbers corresponded to syllables. After a few attempts, he made a breakthrough, with the discovery of “les-en-ne-mi-s” represented by a cluster of numbers (124-22-125-46-345), and thus his idea eventually proved to be right. During that time when cryptography was mainly about encrypting plain alphabets with cipher alphabets, it was creative of the Rossignol to use syllables for the complexity of homophones. More importantly, they had also laid traps for codebreakers, adding numbers which deviously deleted previous numbers instead of representing any meaningful letters or syllables. All their creative encipherment contributed to the strength of its encryption, making it confusing and harder to decipher.
Additionally, after the death of both father and son, the Great Cipher fell into disuse and many details about it were lost; therefore, for those who wanted to break the codes had to start from scratch. Due to its difficulty, only the most prominent cryptanalysts were capable of deciphering it with consistent dedication and patience. As a result, it was no surprise that the Great Cipher was known as one of the strongest ciphers in the history of cryptography.
There exists a never ending battle in the field of cryptography between those coming up with encryption methods and encrypting messages to those trying to break these ciphers. This back and forth is an ongoing and fairly quick process with each side constantly making advancements. However, the 2nd chapter of Singh discussed “The Great Cipher” which was the cipher used by Louis XIV, which remained unbroken for 200 years. The obvious question is then, what made this particular cipher so difficult and take so long to crack?
There are multiple reasons for this, starting with the complexity of the code itself. The code was comprised of 587 unique numbers with thousands of numbers altogether. This alone makes it very difficult to decipher as if you were assuming these numbers corresponded to letters or a set number of letters, as there would have to be repeated elements of the cipher text corresponding to the same thing in the plain text, which would render frequency analysis practically useless. This leads into the next reason why the cipher was so secure, which is that the numbers corresponded to syllables instead of letters or groups of letters. The majority of the ciphers up till this point revolved around changing something into individual letters, so this not being the case probably threw off many would be deciphers of the text.
Lastly, one of the main reasons this code was so secure is the technology that was available at the time. Nowadays with our computers, excel files, other programs and whatnot it is fairly simple and straightforward to do things such as frequency analysis or substituting in sequences in the cipher text for what we assume it to be in plain text. However, back in the 17th and 18th centuries performing these tasks by hand (especially with a text thousands of characters long) would be an incredibly daunting task. The sheer time commitment it would take to decipher a text of this length would be enormous and this probably discouraged many people from attempting to decipher it.
The Great Cipher used by Louis XIV remained unbroken for 200 years. What were the factors that led to such a secure cipher?
The Great Cipher, invented by Antoine and Bonaventure Rossignol, was one of the toughest codes to decipher. There are some very important factors to consider when trying to understand why it may have taken so long for someone to crack it. First of all, Antoine got his recognition for deciphering the letter that resulted in a victory for the French. With his work in cryptanalysis he and his son were appointed to the senior positions in the court, so by this time he has already established his reputation as being one of the best cryptanalysts in Europe. His expertise gives him an advantage because he can recognize the weaknesses in ciphers, therefore when he has to create his own, he would know how to make it indecipherable. Of course, this is relative because ciphers can only stay indecipherable for so long before new methods are developed by cryptanalysts to break them. Second, it is usually a weakness to have a long cipher text because it gives the other person a better chance to recognize patterns, however, this cipher had thousands of symbols with only 587 of them being different. This only makes it a lot more difficult for someone to decipher it because it gives them too much information to work with which instead of showing a pattern, creates confusion. Finally, the more time that passes, the harder it is for someone to decipher a text because of lack of contextual clues. When it is the same time period, there is a better chance to crack a cipher text because you would be fully immersed in the linguistics of that society. Since language evolves over time it is best to try to decipher a code as soon as possible. Because of the complexity of the Great Cipher it did take a lot of dedication and persistence for Bazeries to finally crack it after 200 years.
