Cryptomator looks quite impressive! Though if I may throw a suggestion in to the mix, I quite like rclone. It's also FOSS, with support for a wide range of cloud services.
The one downside for most most people with rclone is likely that it's only a command line interface, so not the most user-friendly thing out there. But on the other hand, this means you're more likely to be able to access your files in desperate situations where all you have available is an internet connection and a terminal. It's also far easier to write scripts for.
Thx for your comment, yeah also for me it looks not very user friendly. Maybe i take a closer look at it. But you can use Cryptomator also as a normal encrypter because you only need a place where you can store your data and the master key for it. So you only need a supported OS. and can also recover your data so long you have the master key and password. But i don't know if a other program can also read the public keys. Maybe you know more? I never try it. ;)
Technically, you only need the public key to encrypt data, not decrypt. Decryption is the job of the private key. Unless I'm misunderstanding your use of the term.
As far as I'm aware, rclone does not use asymmetric encryption (public/private keys), since you're not encrypting the data for anyone else, so it's not really necessary.
I suppose that any program implementing the scrypt algorithm should be able to work with files encrypted by Cryptonator.
As far as programs that are just plain encryptors, there are loads out there - 7zip, VeraCrypt, GPG, and even rclone. Out of those 4, only GPG implements public/private key cryptography, since it's intended for sending encrypted messages to other people, rather than just storing the data for yourself.
Yeah its not called public key it is a master key by Cryptomator. This means that Cryptomator encrypt your data and place a master key. So the only thing what protect your data is your password.