The ALAN TURING
Cryptography Competition.
(edition 2015: #4).
You are reading the website of the 2015 edition of the competition, which ended on Wednesday 13th May at 11:59 pm.

Mike and Ellie will return for a new adventure next year!

The website for that new edition, to start in January 2016, appears in December here. If you would like to receive a reminder around that time by email please look here. For any particular enquiries you can contact us on cryptography_competition@manchester.ac.uk.
The Tale of the

Carbon

Conundrum

Is released!
Is released!
Is released!
Is released!
Is released!
Is released!
Is released!
Announcing

The Alan Turing

Cryptography Day

2015!

Want to come over to Manchester for a bit of live crypto stuff, the prize ceremony and an opportunity to meet the organisers?

# Chapter 3 of the Tale of the Carbon Conundrum.

The following day Ellie was inconsolable. "I just can't believe that Barquith is gone," she said, staring at her uneaten lunch. "And I'm sure I saw a gun up in the gallery. Somebody was about to shoot Lord Porterfield, but Barquith saved him!" She sobbed quietly to herself as Mike looked on awkwardly, choking back his own tears.

"Barquith left us a coded message, so he must have been expecting trouble," said Mike. "We've got two mysteries to solve: who shot Barquith, and who stole the quantum computer?"

Ellie looked up. "The police searched everybody as they left. It said on the news that they searched the whole building and found nothing. And they've no idea how the computer was taken from the locked room!" she said.

"They didn't find a gun either... I wonder if they're hidden in the same place?" mused Mike.

The silence was broken as the bell rang. "Come along you two", said a passing teacher. "Clear that food away: it's ICT next."

The lesson was all about binary numbers. The teacher explained how different number bases work: how we use base 10 because we have 10 fingers, but the ancient Mayans used base 20, and computers use base 2, or binary.

"We already know about binary!" a familiar voice piped out from the back of the room. "Instead of hundreds, tens, and units, with digits 0 to 9, you have fours, twos, and units, with digits 0 and 1", chimed in a second voice.

"Darcie, Donna: stop showing off", said the teacher. "You're right though, in base 10 you count 0, 1, 2, 3 and so on up to 9, then 10, 11, 12, then all the way up to 97, 98, 99, 100. In binary you count 0, 1, 10, 11, 100, 101, 110, 111, 1000, and so on. For example, 1101 in binary means 1 eight, 1 four, 0 twos and 1 unit, so that's 8+4+1=13 in base 10. Now, can you tell me how many binary digits, or bits, I would need to represent all the letters of the alphabet?"

The lesson drew to a close but the class were enjoying themselves so much that they hardly heard the bell ring. As they picked up their bags, Ellie heard a familiar voice behind her. "We knew all of that already!" said Darcie. "We're far smarter than you!" said Donna, as the twins left the classroom.

"Let's see if there have been any developments about what happened yesterday," said Ellie, as she turned on her tablet. She and Mike scrolled through the news stories. "What's that!" said Mike, as one item caught his eye. He read out the headline: "`Lord Porterfield talks about his narrow escape'."

"`Today, Lord Porterfield released a statement paying tribute to the man who died saving his life and called for those responsible to be brought to justice'", said Ellie, reading out the summary. "I think we owe it to Barquith to hear what Lord Porterfield has to say." She clicked on the video.

If this video does not play, then click here to stream from the University of Manchester video repository.

Above is the video of Lord Porterfield reading out his statement, but it contains a hidden message. Your task is to decode Lord Porterfield's statement. Once you have done that, submit your answer to the question below.

Question: What is the 22nd word of the plaintext?