Editing Final Report 2012 (section)

===Cipher GUI===

[[Image:CipherGUI.png|thumb|350px|right|Cipher GUI Interface.]]

In the course of evaluating a range of different ciphers, the group last year developed a Java program which could both encode and decode most of the ciphers they investigated. Part of our task this year was to double-check what they had done. To do this, we tested each cipher with both words and phrases being encoded and decoded, to look for errors. Whilst most ciphers were faultless, we discovered an error in the decryption of the Affine cipher that lead to junk being returned. We investigated possible causes of the error, and were able to successfully resolve a wrapping problem (going past the beginning of the alphabet C, B, A, Z, Y... was not handled correctly), so now the cipher functions correctly both ways.

We also sought to increase the range of ciphers covered. One example we found was the Baconian Cipher, whereby each letter is represented by a unique series of (usually 5) As and Bs (i.e. A = AAAAA, B = AAAAB, and so on).  Whilst this was known of during the Somerton Man's time, the use of letters besides A and B in the code clearly indicates the Baconian Cipher was not used. Despite this, the Baconian Cipher would have made a useful addition to the CipherGUI. However,  the nature of the way it was coded, and our lack of familiarity with the program, made the addition of further ciphers difficult, so we decided to focus our efforts on other aspects of the project.

Last year's group did a lot of good work developing a "Cipher Cross-off list", which went through a range of encryption methods and determined whether it was likely or not that the Somerton Man passage had been encoded using them. We analysed their conclusions, and for the most part could find no fault with their reasoning. However, they dismissed "One-Time Pads" wholesale, arguing that the frequency analysis of the code did not fit that of an OTP. However, they assumed that the frequency analysis of the OTP would be flat, since a random pattern of letters would be used. This is fine for most purposes, but if the Somerton Man had used an actual text - for example the Rubaiyat - then its frequency distribution would not be flat. It is for all intents and purposes impossible to completely discount OTPs as the source of the cipher, since the possible texts that could have been used - even ignoring a random sequence of letters - is near infinite. You cannot disprove something for which no evidence exists; you can only prove its existence by finding it.