This month's cipher

This month's cipher awaits a worthy adversary. First correct answer wins. Winner announced, and their method examined with suspicion, next issue.

The Challenge is verified by hand before publication, not by a machine, on the grounds that a machine cannot be made to look appropriately smug about it afterward. Last month's cipher was solved by a reader who described the process as “a genuine waste of a Tuesday,” and who has asked to remain anonymous, a request we are respecting by referring to them only as last month's winner.

Entries close the Wednesday before the next edition. No correspondence will be entered into, mostly because nobody here is confident enough in the cipher to defend it under questioning.