Cryptography

The History and Mathematics of Codes and Code Breaking

Tag: Mary Queen of Scots Page 1 of 3

Environmental change in Cryptological Perception

Mary Queen of Scots fully believed that her cipher was unbreakable, so she laid bare her plan to take control of Scotland. Thus when her cypher was encrypted, there laid a written confession on the table, ready to take her to the gallows. This historical example led to the development of an environment of secrecy and mistrust, where cryptanalysts held the power over cryptographers. Even if one made a seemingly "unbreakable" code, they did not know if another expert codebreaker was waiting to crack it. This never-ending cat-and-mouse game of codes has continued through the centuries, always adapting and evolving. The knowledge that one's code could be broken fostered more caution on behalf of the cryptographer, wherein they sent codes that were more cryptic in nature even in plaintext, knowing that an expert codebreaker might crack their code.

This strategy was a direct consequence of the knowledge that someone more experienced may crack your code - after all, if that was the case, why not make your plaintext message more difficult to understand as well? This would add an additional layer of security, and ensure more protection.  This shift was a significant one in cryptography history, and represented a transition to a more secretive/hard-to-decipher language where nothing was taken for granted.

The Perils of Hubris in Cryptography

On page 41 of Simon Singh’s The Code Book, Singh makes the interesting assertion that “a weak encryption can be worse than no encryption at all.” This seemingly paradoxical statement reveals how hubris can be the downfall of any great cryptographic scheme. Best exemplified in the case of Mary Queen of Scots, when two parties deem a cipher or code secure and therefore write their messages freely with no fear of discovery, this overconfidence can ultimately result in their downfall. Had Mary’s messages not been so explicitly linked to the assassination plot of Queen Elizabeth, and instead been deliberately vague, the evidence against her would have been weak enough to possibly save her life.

The beheading of Mary Queen of Scots should serve as a cautionary tale to any modern cryptographer to remember the possibility that your enemy has already cracked your code, or that another part of the world is already much advanced in the art of code breaking. A good cryptographist should take extra precautions when crafting their message to ensure that, if the encryption fails, the implications of their message, should it land in the wrong hands, are as limited as possible. No code should be deemed unbreakable by its creators, and stenography and subtlety of language are just as crucial in encryption as a strong cipher or nomenclature.

Inviting Suspicion

We generally don't bother to encrypt messages if we have nothing to hide. By using a code or cipher, it's implied that the contents are sensitive or illicit in nature. In fact, as Singh points out, they're likely to be more explicit because the encryption lulls the sender into a false sense of security and they write more openly about their plans. So by putting too much faith in an easily breakable cipher, you risk incriminating yourself further.

In addition, by using a cipher or code that is easily identifiable as such, you automatically invite suspicion.  In her trial, Mary claimed she knew nothing about the plot, but even without decrypting the message, it was clear she was corresponding with conspirators. Also, the fact that she didn't write her message in plain text implies she was concealing something. In situations like these, it may be better to stick to some sort of code that masks the message as something innocuous, or some sort of steganography that hides the secret message within another. By finding a way to hide a message in plain sight, it helps divert suspicion in the first place rather than relying on an imperfect cipher once you've drawn attention.

Weak Encryption VS No Encryption

The meaning of the sentence is that the consequence which is caused by weak encryption is worse than that of no encryption. First of all, a weak encryption can be easily deciphered. Once it has been deciphered, the enemy will get to know the hiding information and know the secret between lines. In the scenario, it causes the failure of Babington’s plan and causes the death of the members and Mary Queen of Scots. Secondly, the weak encryption creates an illusory secure. This means that both Babington and Mary Queen of Scots think their plan will not be reached by their enemy. With this feeling, they just keep on using the same method without doubting the possibility of exposing information to Walsingham. Finally, weak encryption creates secrets compared to no encryption. The enemy will spend more time on decoding it in order to get to the secret and get prepared for the scheme of their enemy.

For the people who want to hide their communications, they must use strong and new cryptographic methods to keep their information from deciphering easily by their enemies. In this story, the method of using frequency of the symbols has already applied at that time. Although Babington uses new symbols and kind of different encryption, Phelippes just uses the frequency method to decipher it. The methods of encryption decide whether the secrets can be easily got by enemy or not. What’s more, the sender and the recipient need to change their encryption from time to time and they also need to make sure the person who send the message is not a spy. With all of these, the possibility of divulging a secret will decrease and creates a safer environment for transfering the secrets.

The Cryptographic Needs of the Common Man

It is said that history is written by the winners, but many forget the second part of of that statement, that history is also written about only the powerful and important. The examples of cryptography that survived throughout the ages were those that caused great uproar, such as the beheading of Mary Queen of Scots.

Besides, the common man did not have much need for cryptography before the invention of modern technology. Unless communicating about a potential insurgency plot, most people did not need any form of secret keeping. It was often unnecessary to require a secret address to the nearby woods where their secret stash of gold was buried.

The primary difference between the times then and now, is the amount of information on a person that could be used with malicious intent. Compared to the 16th century, where a person's identity was comprised of a family name, some heirlooms and the land upon which they lived, today every person is a collection of numbers and electronic impulses. Whether it is Social Security, bank account numbers, credit card numbers or even account passwords, today there is every possibility for the threat of theft.

As society continued to advance away from the tyrannical rule of the monarchies that was so well documented in chapter 1, people began to look towards their right to privacy. In the 16th century the only reason to conceal common correspondence was usually an indication that there was something to be concealed in the message. Today however, people use encrypted communication for every day conversations, to ensure their privacy, no matter the message. Electronic communication means that almost any message could be at least intercept, an impossible task with physical messages. The importance of encryption for the common man has grown tenfold.

The Consequences of Weak Encryption

One may assume that any type of encryption is better than no encryption, but for many situations, that may not be the case. Take the story of Mary Queen of Scots. Her weakly encrypted correspondence with Babington was interpreted by expert cryptanalysis Phelippes, leading to her eventual execution. Mary and Babington were so confident in their substitution cypher that they explicitly spoke about their plans to assassinate Queen Elizabeth. Unbeknownst to them, there had been huge advances in the field of cypher-breaking. Had Mary and Babington possessed an accurate sense in the weakness of their cypher, their conversation would have been far more discreet, taking care to discuss their plans in a more cautious manner.

This form of explicit versus discreet communication can be seen in everyday situations where cyphers are not involved. For example, if a group of bilingual people want to talk about someone nearby without their knowledge, the group will most likely switch to the second, less widely-spoken language. They would talk about said person without any filters, as they'd assume that no one around them would be able to understand what they are saying. However, if the group of people aren't lucky enough to have a second language to fall back on, they will probably communicate in a more discreet manner, with facial expressions and gestures, rather than clearly spoken words.

The case of Mary Queen of Scots could be a lesson to anyone who wishes to communicate through encryption- communicate as if your cypher is breakable, no matter how secure you might think it is.

 

The Race Between Cryptanalysis and Encryption

The status quo of cryptography can be accurately represented by a game of tennis between two equally good players. When a strong cipher is developed, the ball moves to cryptanalysis. Upon development of better decryption techniques, the ball returns back to the court of the encryptors. The period in which an event happens in the world of cryptography is heavily influenced by who has the power between cryptanalysis and encryption.

During the time of Mary Queen of Scots, the users of cryptography had little to no faith in the abilities to decrypt, causing them to have  undue faith on their abilities to encrypt. By not giving sufficient credit to cryptanalysis, they did not bother with either reinforcing the difficulty of the cipher  or any sort of counter measures in case the cipher was broken, leaving them in a worse position had they chosen not to encrypt. On the other hand, the situation before the Vigenère cipher was the exact opposite as the strength of any cipher was presumed to be weak. Encryptors were motivated to fortify their ciphers and even after encryption, they would communicate in  ways that would seem senseless without context. Some would even avoid cryptography altogether and find other ways to convey the desired message.

I also believe that during the period of Mary Queen of Scots, cryptography itself was fairly new and unheard of. This meant that almost no one had any idea how to encrypt (and naturally, decrypt) ciphers. After cryptography became more popular, more people explored the avenue and cipher breaking became more ubiquitous. This was another reason for encryptors to strive to strengthen their ciphers.

Uncertain Environments Generate Safer Practices

An environment in which one knows he or she must constantly maintain precautions is safer than one where they are unaware of the dangers that potentially exist.  

This concept is exemplified in the case of Mary Queen of Scots by the simple fact that her naive belief that she was speaking in secrecy directly resulted in her death. She essentially signed up for her own funeral by openly disclosing matters of treason. If she had been living in the era in which it was common knowledge that a “codebreaker might intercept and decipher their most precious secrets,” (Singh, p.45) then it is much more likely she would have been less forthcoming with the information she provided in her encrypted messages.

The new environment created was far more advanced than anyone in her time could have predicted. Mary’s generation falls in the era of monoalphabetic substitution, whereas the new age moved on to as many as twenty-six (polyalphabetic). Furthermore, everyone in this new era of cryptography frequently changed their methods. They would not be caught dead using such a basic cipher over a prolonged period of time to transport such crucial information. Even the ciphers used for general business information transported by telegraphs was more secure than the cipher Mary trusted her life with.

The new environment of encryption even allowed for progression in the cryptography field. As ciphers became more complex, more professional codebreakers emerged that continued to prove how difficult it was to create an uncrackable code. In turn, this generated more ciphers and the loop continues from there. Progression did not just make the population more cautious, but it also generated societal growth.

The Nature of Cryptography

In Cory Doctorow's novel "Little Brother", the passage which resonated with me the most was the one on page 57 where Marcus had just given up his phone password to Carrie Johnstone. In this passage, he begins to explain the essence of cryptography and the reason why it stood out the most was that in that one short passage, he went over almost everything that we have done in historical aspect of our cryptography class.

Firstly, he touches upon the fact that cryptography  used by the common man is just as strong as the one used by the National Security Agency. This is representative of the progress we've made as compared to the cryptography used by Mary Queen of Scots, a topic we discussed in detail as the first chapter of Simon Singh's "The Code Book". In that chapter, we see how niche cryptography was and more so cryptanalysis whereas now it is a ubiquitous phenomenon, very often taken for granted.

Secondly, Marcus talks about how his privacy was in question, again something we have deliberated on as we weighed out the balance between public safety and privacy. Reading between the lines, it is also seen that when it comes to cryptography, having enough resources can always crack the code, regardless of the ethics of the means you use to do so. Just like in the San Bernardino's case, the FBI found a way to get past the encryption, the DHS were able to pressure Marcus into giving up his own privacy, which begs the question that in an absolute sense, can anything ever be kept completely secret?

Finally, Marcus asserts that the best means of measuring the efficacy of an encryption is its prevalence. This argument runs parallel to the ideas of Joseph Bramah's challenge as explained in "Perfect Security-99 Percent Invisible" where he  explains the mechanism behind it and still exacts the public to try and open it. The fact that his lock was not picked for a substantial period of time reinforces the level of security it provided to its user.

Never Trust A Weak Encryption

In the first chapter of The Code Book by Simon Singh, he states that “a weak encryption is worse than no encryption at all”. A weak encryption is worse than no encryption at all because the sender and receiver of the message believe that the message is secure. A weak encryption leads to a false sense of security. If someone was to send a message with no encryption, they would know that their message was floating around and would be more cautious. People that send encrypted messages should always be mindful of what information their message contains. Over time many messages can be decrypted, and a sender of an encrypted message should remain mindful of that. No one should put all of their trust into a encryption since the message could possibly be deciphered. People that want to keep their messages secret should keep their messages very vague even if they are encrypted. There is always a chance that a message can be decrypted, so the sender should not only rely on a encryption to make sure that their message is secure. Mary Queen of Scots should have been vaguer with the messages that she sent. Since she truly believed that her messages would not be decrypted, she was not withholding the information that she sent. Her trust in the encryption led to her execution.

 

Page 1 of 3

Powered by WordPress & Theme by Anders Norén