LegalFling aims to make the sexual dos and don’ts explicit in a “fun and clear way,” according to its website.

Condom use, bondage, dirty talk, sexting: the app lets users set their boundaries before an encounter — boundaries that can be adjusted at any time with a tap and shared with a potential partner. (Sound familiar? Netflix’s twisted-tech series “Black Mirror” incorporated a similar transaction in its episode “Hang the DJ.”)

“A profile update is an event we store on the blockchain and will subsequently update the live contract,” Rick Schmitz, a co-creator of LegalFling, recently said. The transaction is encrypted, timestamped and stored. (A blockchain is a collection of digital transactions that are registered in a sequence of “blocks” of data.)