What generic encryption method to use to transfer a string from client to server?

Question

Encryption

There is a project that has a backend server (API) and clients - they all use different programming languages: PHP, Java, C++, ......
Question: Which encryption method / library to use to transfer data (json strings) between the client / server that both could decrypt knowing only the password?
PS. At the moment I see only openssl encrypt/decrypt.

Answer 1

PS. At the moment I see only openssl encrypt/decrypt.

Here openssl and use.
Choose an encryption algorithm, for example, AES-256-CBC and google for each specific language how to encrypt and decrypt a string / byte array.
Here I answered a similar question: Is it possible to transfer encrypt / decrype over the OpenSSL network?