Google has enabled the RCS encryption capability by default for Messages. The company has recently published the related information on the official support page, saying that the RCS conversations are now fully end-to-end encrypted, including group chats.
So far, the US tech giant initiated this facility on June 2021 and is finally rolling it out gradually among users. Eventually, the motive is to ensure more people benefit from this added security. In case you don’t want to use encryption services, you can turn them off at any time via the Messages settings > RCS chats menu.
Ahead, Google notes that when RCS encryption is running by default in the Messages application, there are lock signs throughout the conversation. All participants must turn on RCS, but there is otherwise nothing you have to do, and cannot disable it.