What TV understands about crypto

One of only two shows that we actually watch on television is “Murdoch Mysteries.”  Set in Toronto, circa 1900, it shows Detective Murdoch “inventing” much of modern forensics using the technology of the time.  Some of it might actually work  :-)

The latest episode, “Invention Convention” (season 5 episode 9) had someone promoting “i-mail” (instant mail). which Gloria thought was Telex, and I figured was more akin to fax.  (For those in Canada, CityTV runs “Murdoch” a number of times during the week, but won’t say which ones are the current season, and which are older.  I’m pretty sure this episode will be relayed at 8 pm on Saturday.  For those outside Canada, I’m not sure whether you can watch the episode on the Website.)  Part of the plot turned on someone sending encrypted messages.

The code used by the group is a form of Ceasar cipher, aided by an Alberti disk.  In reality, by 1700 this probably would have been considered old hat: Casanova writes of breaking what must have been at least a shuffled alphabet cipher.  (In the episode an “analytical engine” is used to try and brute force the Ceasar cipher.)  Autocode and other forms were well established by 1900.  (De Vigenere created one form of autocode, rather than the cipher which bears his name, which he considered weak.)

In the end, the code turns out to be based on a keyboard layout, which probably was not completely standard by that time.  Which would, in any case, have been a simple substitution cipher, and easily breakable by frequency analysis (one case of which was said to have failed in the plot).