Data encryption/decryption at rest

Hi guys,

We have some ETS tables persisted to disk periodically.

These data are almost static (rarely change) and contains clients
information such as: name, gender, date/place of birth, security token, etc.

Due to new policy in place, these data has to be encrypted at rest.
But I still need to access it in a decrypted way inside my Erlang app.

What approach should I take?
Is there any Erlang library to help with this task?

Disclaimer: I’m by far not a security expert

Thanks
/Frank