Is your feature request related to a problem? Please describe.
The current size of 2048 for RSA keys is not considered adequate.

Describe the solution you'd like
AFAICT, the change needs to be made here. This might be a quick/easy change, only affecting new key creation and encryption, as long as

• it won't break existing encryption functionality
• and won't require users to replace their keys.

Anyone who wishes to use the larger key size can then manually remove encryption, replace their key and re-encrypt.

I don't see a way to replace the encryption keys in either the GUI or the scripting/plugin API. This would need to be implemented and documented, including the re-encryption (with the new key) of any encrypted items/tabs.