extent to which governments can access our private lives. Putting this together with my experience of breaking codes for Dulwich Inventive, the importance of the encryption used by social networking providers suddenly dawned on me. But, if I can crack the Dulwich code, how confident should we be of the protection these providers offer? How sure can we be that Big Brother is not watching us after all? I was compelled to read more about cryptanalysis, despite the fear of incurring a ‘no prep’ from my teachers the following day. The study of codes, with the intention of deciphering them without keys, has a long history: from work by the 9th-century scholar Al-Kindi to the decoding of key documents in the Babington plot of 1586, which led to the demise of Mary Queen of Scots, to the use of the Enigma Machine by German Intelligence in World War II and the success of Alan Turing and his team at Bletchley Park in deciphering its messages. The art of intelligence, security and counterintelligence has been a never-ending rat race and encryption algorithms are just the next step. Helpfully, the STEM day, part of Dulwich Inventive week, had given me the chance to see the Enigma Machine up close. After marvelling at the ingenuity of this contraption, I felt driven to read up on Turing and his further scientific contributions. Turing’s Automatic Computing Engine marked the start of the extraordinary proliferation of computers in every aspect of society; and as the use of modern computers has increased, so has the need for more secure data transactions. Coherent, structured arrangements of numbers and letters must be transformed into an incoherent muddle of untranslatable gibberish before being sent to a recipient, and then reconstructed at the other end in its original form – all in the blink of an eye. Understanding how modern-day encryption works means encountering numerous acronyms such as DES (data encryption standard) and AES (advanced encryption standard). But it is easier to understand encryption algorithms, or ciphers, if we think of them as merely providing a way to craft a message and give a range of possible combinations. A key helps the recipient to decipher the possible combination. Such ciphers are mostly used for two different types of encryption: symmetric-key encryption and asymmetric-key encryption (also known as public-key encryption). A metaphor might help to make the concept even clearer. Chris wants to send a message to Jane and does so by putting a message in a box and locking it with a key. He sends the box to Jane, who has an exact copy of the same key, and so can open the box, read the message and reply by locking her message in the box with the same key. In the digital world, this would be symmetric-key encryption and the box and padlock are the encryption algorithm, which turns the message into an incomprehensible jumble of characters. Symmetric-key algorithms can encrypt data one
The study of codes, with the intention of deciphering them without keys, has a long history
Breaking the codes during Dulwich Inventive
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