GCHQ, however, remains skeptical, stating that without the exact codebook, or full details of the encryption, it's impossible to verify any alleged solution.

ENGADGET: Alt-week 12.22.12: strange skulls, solar portraits and 17-minute code cracking

Gord Young, from Ontario, inherited a codebook which he thinks holds the key, believing the message relies on a cipher also used in World War I.

ENGADGET: Alt-week 12.22.12: strange skulls, solar portraits and 17-minute code cracking