[jmnicolas]

I would use something like 7zip.

However my unsophisticated parties are really too unsophisticated or too lazy so I send it in clear.

This is why you will not find a comment from me throwing stones at Equifax or other orgs that had breach.

[tomsyouruncle]

Thanks yeah 7zip looks useful although the standard macOS unzipping utility can’t decrypt it when it’s encrypted using AES256 (not sure if windows can natively). Hence I’m concerned that the third party will also need a copy of 7zip...