Elixir Version of Javas Encrypted Class Files? -> Securing Elixir Code

So you write a module, encrypt and save to disk/db, application reads it and loads module? Where does the encryption key live?

Currently on the encrypted file which isn’t good.
So I would change my question to, what is the best way to go about securing an important module, so that if I am hacked, the hacker cannot see the encryption methods I am using, and therefore decrypt all data.

If the module is unencrypted in memory, then they can dump all of that. If you encrypted the module, then you also have key for that encryption stored anywhere in the memory or in a file that is readable by current application.

In short, it doesn’t really make sense to me to encrypt the BEAM files.

The module would be created then encrypted and the original deleted, the module would not be stored anywhere in an unencrypted format, but I can dismiss this idea if you think it doesn’t make sense, because as you stated key storage is a problem.
Would you suggest a different method of keeping my elixir encryption method secret in case of a dump?

You must secure the keys. Not the methods.

A motivated attacker can likely guess or infer the method based on structure of the encrypted blob.

I see, this was in-part motivated by the recent Twitch dump… Really don’t want that happening to me.

Just use method properly, then even if there will be a breach, as long as the key do not leak, you will be safe. There is little to no point of keeping encryption method secret. It can help with slowing down attack, but itself it does nothing. As long as your protocol do not have flaws and keys are secure then forcing yourself with hiding encryption method is pointless. See at the TLS where encryption method is actually public.

I’d like to second what @hauleth said.

You should be able to reveal how you encrypt data (minus the key) and that data should still remain effectively safe. That is the overall meaning or expectation behind strong/good encryption (I’m “colloquializing” but for simplicity’s sake).

You don’t want to have an encryption method that’s strength is due to the obfuscation of the method. That would render it effectively weak or not good encryption and would provide a false sense of security for you and the people depending on the encryption.

I’m not sure for your particular use-case what strategy you may want to take, but the enacl library mentioned in my other post is an elixir library that enables you to work with the world class NaCl/libsodium libraries.

So, storing keys separately is typically how it’s done. There are even key management services you can use that are more sophisticated ways of, again, storing keys separately so that if your encrypted data is obtained, it’s not necessarily obtained with the keys to decrypt it.

Cloak is another elixir library that is geared more toward what it sounds like you’re trying to do: encrypted at rest in the db (cloak_ecto too if dealing specifically with ecto).