* Support salt in DeriveKey

* Revert "Support salt in DeriveKey"

This reverts commit b295ae42673308a2d66d66b53527c6f9aba92ac9.

* Refactor out key derivation, symmetric encryption, and symmetric decryption into generic functions

* comments

* comments

* go mod vendor

* bump both go.mods

* This one too

* bump

* bump

* bump

* Make the lesser used params of symmetric ops a struct

* go fmt

* Call GetKey instead of DeriveKey

* Address feedback

* Wrong rv

* Rename calls

* Assign the nonce field

* trivial change

* Check nonce len instead

* go mod vendor