Cryptomator provides transparent, client-side encryption for the cloud (and locally, too).
The program creates an AES-encrypted file in your Dropbox folder, Google Drive, or whatever other location you like. Just specify the file name, location and a passphrase, and you're done.
Once the vault is set up, Cryptomator mounts it as a virtual drive on your computer.
Save any documents to that drive, and they're automatically encrypted, then uploaded to the cloud (if this is a cloud storage folder).
When you're finished, lock the vault, the virtual drive disappears, and no-one will even know it's there.
Cryptomator is available on multiple platforms, allowing access to your data from almost anywhere, but keep in mind that the iOS app is a commercial product ($4.99).
Verdict:
A simple way to secure your cloud files, and access them from just about anywhere.
Your Comments & Opinion
Automatically encrypt/ decrypt your cloud data
Automatically encrypt/ decrypt your cloud data
Quickly protect and share files with AES 256-bit encryption
Track and recover your lost or stolen laptop with this free tool
Maintain the security, privacy and performance of your computer
Create secure passwords, store them safely, then drag and drop to use them with this powerful security tool
The secure chat app is now available everywhere
The secure chat app is now available everywhere