Broadchurch cast and crew are said to have been so keen to keep the plot of the second series under wraps that they used encryption to make sure scripts and plots could not be leaked.
Bosses apparently used a combination of coded scripts and a crack security team to make sure that no storyline details were revealed, according to The Sun.
As ITV's murder mystery drama, which stars David Tennant and Olivia Colman, heads into its second series, the cast have stressed that they have been sworn to secrecy about what will happen. But they reportedly signed non-disclosure agreements, which would have seen them fired if they had spilled any details.
Scripts are thought to have been issued and the series filmed under a false name and call sheets used pseudonyms for the cast. All character names were taken out of the scripts, which were only handed out a few days before filming scenes, and all digital documents were kept firmly under password protection.
Added to these special measures, a team of ex-military guards are said to have been hired to patrol the set.
Meanwhile, creator Chris Chibnall has warned that none of his characters are safe this time around - even detectives Alec Hardy and Ellie Miller, played by David and Olivia.
According to the Daily Mirror, he teased: "No one is safe. Who knows who will be standing at the end?"
Broadchurch returns to ITV tonight (January 5) at 9pm.