I have a bit of data that has to be encrypted and stored into a file so that it can be moved across file systems and possibly OSes. Disk encryption like dm-crypt and a loop device isn't appropriate as it may not exist on another OS.

It's been a very long time since I needed this sort of software. More than a decade ago I used TrueCrypt. I know that VeraCrypt is the current re-incarnationn of the project. Is that still the go-to software for this sort of application? Is there something else that's popular these days?