The Cipher of Mary Queen of Scots Quiz

Answer: Plotting to assassinate Queen Elizabeth I of England

Mary was born in December 1542, the daughter of James V of Scotland. However, having suffered a crippling military defeat to the English he had a breakdown and died shortly after her birth. As the only heir, Mary was crowned on the 9th September 1543, aged just nine months.

From an early age there were attempts for Mary to be suited by Edward, son of Henry VIII, in order to unite the two nations. However, Mary's mother, Mary of Guise had other ideas. As she was French she decided that it would be better for Mary to move to France (which she did at the age of six) in order to marry the Dauphin Francis and unite Scotland and France. When she was sixteen they married. Then in 1560, when Francis had been king for less than a year he fell ill and Mary was widowed.

When she returned to Scotland in 1561, she realised that her Catholic faith was likely to be shunned as many in Scotland were edging towards Protestant Christianity. Mary was imprisoned by Scottish parliament due to her Catholic faith, and having lost control of the Scottish crown she was forced to seek refuge with her cousin, Queen Elizabeth I of England.

Rather than provide refuge, Elizabeth imprisoned Mary as she saw her as a threat to her throne. Mary then lived out the rest of her life in prison leading up to her plot to assassinate Elizabeth shortly before her death.

Answer: Babington Plot

Anthony Babington was a young Catholic who was very supportive of his faith at a time when it was difficult to be so. Catholics were forced to pay huge taxes and religious leaders could often be subject to gruesome consequences such as disembowelment or mutilation.

It was for these reasons that Babington was in support of Mary becoming Queen, as she was a Catholic who would put a stop to all of this. Also, many English Catholics believed Elizabeth to be an illegitimate Queen as she was mothered by Henry VIII's second wife Anne Boleyn. As Catholics did not allow the concept of divorce they believed that Henry could not have married Anne legitimately and therefore Elizabeth was a bastard child.

In March 1586, Babington and other conspirators gathered to discuss the plot that would involve the assassination of Elizabeth and the freedom of Mary. However, they felt that they needed Mary's blessing to carry out their plan, and so the secret correspondence began.

Answer: Inside a leather packet inside the hollow bung of a beer barrel

Despite many of these sounding ridiculous, it is known that all four techniques have been used at some point in history. The 'shaved head' and 'wax ball' techniques are older and would clearly be used when there wasn't a great deal of urgency for the message to be delivered as it would take time for the hair to grow back or the ball to be passed.

The 'urine' technique is still used today as invisible ink when easier methods are not available. The urea burns brown when heated gently and the message can be discovered easily.

However, the 'beer barrel' is the right answer. Gifford (their courier) would go to the local brewery and use the bung to conceal the letter. Then somebody working at the place where Mary was held would open it up and deliver the message.

Answer: The practice of keeping the message hidden

The practice of encoding or enciphering the message is known as cryptography, and is viewed as a separate discipline. On the other hand, steganography involves keeping the message itself hidden, regardless of whether or not the message is encrypted. The practice of steganography has existed for several millennia, with the earliest known examples being some of those in the previous question (Shaved head or wax ball technique). Clearly these methods would have taken a while to carry out and as time progressed, faster methods of hiding the message had to be used.

This gave rise to invisible ink and other more modern methods of steganography.

Answer: Nomenclator

A Nomenclator will generally have one letter/symbol as a substitute for each letter of the alphabet and also a short selection of commonly used words or phrases which may be represented by separate symbols.

For example in the cipher that Mary used, there were 23 symbols representing single letters (excluding j, v and w) and also 35 other symbols that represented words and phrases such as 'mine' or 'your name'. A polyalphabetic cipher is where multiple cipher alphabets are used to encipher different parts of the message. An example of this is the Viginere cipher. The other two options are made up.

Answer: A nonsense symbol thrown in to confuse the analyst

It is clear to see how the presence of nulls would add to the security of the message. Given that both sender and receiver are aware of any nulls that may be present in the text then it would be easy to disregard them. However, if a cryptanalyst was trying to break the cipher and read the message then nulls give a clear advantage for the sender as the presence of nulls may deter frequency analysis as it would throw up false truths.

Answer: The next symbol represents a double letter

The dowbleth indicates that the next letter or symbol represents a double letter. This is another useful security tool as it deters frequency analysis by potentially halving the number of one letter that occur in the message. Also, the dowbleth itself could be seen as a separate symbol, again causing havoc with frequency analysis.

An example of how this would work can be seen by writing out the word MISSISSIPPI with a dowbleth symbol of '+'

In the normal word there are - 4 I's, 4 S's, 2 P's and 1 M.

MI+SI+SI+PI

In this case there are - 4 I's, 3 +'s, 2 S's, 1 P and 1 M.

Obviously it would be easy to decipher the message in this case despite the differences in frequency of each letter, but if a whole letter was enciphered then the differences in frequencies could throw an analyst off of the track.

Answer: e, t, a

A sample of 100,362 alphabetic characters was taken from novels and newspapers in order to compile a chart of the relative abundance of each letter in normal English text.

This showed that around 12.7% of letters used in the English language are the letter 'e', 9.1% are the letter 't' and 8.2% are the letter 'a'. Therefore these three letters are the ones which a frequency analyst would expect to be most common when trying to decipher an enciphered message.

For reference 'o' has a relative abundance of 7.5%, 'i' has 7.0% and 's' has 6.0%. The least commonly occurring letters are 'q' and 'z' with only 0.1% relative abundance each.

Answer: Yes

This was probably the greatest downfall of Mary and Babington's secret communication. The fact that they believed their method of communication to be secure meant that both of them spoke explicitly about their plans.

This meant that if the letters did fall into the wrong hands (as they did) and were deciphered then their intentions would be clear and prosecution would be easy.

Also, their belief in their cipher meant that Phelippes was able to add on to some of Mary's letters requesting the names of Babington's 'fine men' which would eventually lead to their conviction and execution.

Answer: To prevent them becoming religious relics

As Mary was a Catholic, Elizabeth's Protestant subjects believed that any of her clothes, artefacts or even the execution block may have become religious relics and therefore rallying points for any Catholics that remained in England. As this was the time of Protestants, any Catholic uprising was discouraged and therefore everything was burnt.