Encrypted data before store via API

Hello. I want to store my creditionals via API. I found this documentation https://docs.cozy.io/en/cozy-stack/bitwarden/#post-bitwardenapicipherscreate. Problem is that in this documention we have encrypted data but we don’t have an information how can I encrypted this data. This end-point works but data in BW is empty. How can I encrypted this data? I use VaultWarden.

Anyone knows how I can solve my problem?