Messaging app Signal's founder and Chief Executive Officer Moxie Marlinspike will step down and WhatsApp co-founder Brian Acton will become the interim CEO, Marlinspike said in a blog post on Monday.

"It's a new year, and I've decided it's a good time to replace myself as the CEO of Signal", he said. Marlinspike, who will remain on Signal's board, said he is scouting for candidates for the permanent CEO position.

Acton founded Signal's rival messaging app WhatsApp in 2009. The company was bought by Meta Platforms (FB.O), then Facebook Inc, in 2014. He left WhatsApp in 2017 due to differences around the use of customer data and targeted advertising, according to Signal's website.

In February 2018, he alongside Marlinspike, started the non-profit Signal Foundation, which currently oversees the app, by providing an initial funding of $50 million.

Signal, an end-to-end encrypted messaging platform, has been endorsed by people including Twitter Inc co-founder Jack Dorsey, and whistleblower and privacy advocate Edward Snowden.