The ransom demand arrived one recent morning by email, after about a dozen guests were 
locked out of their rooms at the lakeside Alpine hotel in Austria.
The electronic key system at the picturesque Romantik Seehotel Jaegerwirt had been infiltrated, and the hotel was locked out of its own computer system, leaving guests stranded in the lobby, causing confusion and panic.
“Good morning?” the email began, according to the hotel’s managing director, Christoph Brandstaetter. It went on to demand a ransom of two Bitcoins, or about $1,800, and warned that the cost would double if the hotel did not comply with the demand by the end of the day.