Super Secure Individual File Encryption

I'm a bit of a noob to computer security and I've seen a lot of posts on this reddit and others that talk about solutions for encrypting folders and cloud storage but I'm really just looking for info on the most secure way to encrypt a single file within a mac computer. I've heard about using 7zip to compress and password protect a file but some people have said this wouldn't hold up against a skilled hacker. Any thoughts or …

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