Storing important files online is convenient, but it also poses a security risk. Even if your cloud service offers encryption, that won’t necessarily keep your data safe, as if someone manages to obtain your account password then they’ll probably be able to access whatever they like.

If you need real privacy, then, you might want to consider encrypting files before they’re uploaded. This adds a useful extra layer of protection which makes it far more difficult for an attacker to view your files. And it doesn’t have to involve any real extra work, either – the open source CryptSync makes the process almost automatic.

The program works by setting up pairs of folders. Just create a new source folder to hold your local, unencrypted copies of any files. Point CryptSync at this, providing your cloud storage folder as the destination, and that’s essentially it: anything copied or saved to the source folder gets encrypted by 7-Zip, synced to the destination, then uploaded to the web.

All the key encryption and syncing details are set up in a single simple dialog box

The synchronisation works both ways, too. If a file is changed in the encrypted folder then CryptSync will detect this and update the decrypted version. (Or that’s the default setting, anyway – you also have the option to turn this off and simply mirror the contents of one folder to the other.)

There are some obvious complications. In particular, if your cloud files are encrypted then you can no longer immediately access them from any device or browser; you’ll always need a decryption tool to hand.

Still, using CryptSync doesn’t mean you have to encrypt all your online files. You might use the program to protect a few personal documents, while leaving media files as they were before. At least that way you’ll still be able to stream music, say, even if accessing other files is a little more complicated.

On balance, then, CryptSync does provide a convenient and largely automatic extra layer of protection for your cloud storage files, and if you’re concerned about their security then it may be worth a look.