The cloud is a convenient place to back up and store files, but you should hesitate before uploading that sensitive data, whether you’re using Dropbox, Google Drive, or SkyDrive. Sure, your files may be encrypted in transit and on the cloud provider’s servers, but the cloud storage company can decrypt them — and anyone that gets access to your account can view the files. Client-side encryption is an essential way to protect your important data without giving up on cloud storage.
Encryption does add some complexity, however. You can’t view the files in the cloud storage service’s web interface or easily share them. You’ll need your encryption tool to decrypt and access your files.
Encryption is ideal for sensitive files, but you don’t have to encrypt everything. Be sure to use a strong passphrase when setting up encryption, too.
Create A TrueCrypt Container
TrueCrypt is a do-it-yourself method of encryption. With TrueCrypt, you can create an encrypted file container and save it to your Dropbox folder. This file is a big, encrypted blob — no one can see the inside of it without your passphrase. TrueCrypt can mount the encrypted file container as a drive letter or fodler on your computer. Files you place inside the special TrueCrypt drive or folder will be encrypted and stored inside the TrueCrypt file container in your Dropbox folder. Our guide to creating and mounting an encrypted file container with TrueCrypt will walk you through the process.
Why Dropbox? Good question. Dropbox can synchronize only the changed portions of large files, while Google Drive and SkyDrive can only synchronize entire files (as far as I can tell). This means that, if you have a 2GB TrueCrypt drive and change a small file in it, Dropbox will upload a small portion of the TrueCrypt file, while Google Drive and SkyDrive will re-upload the entire 2GB file. Some other cloud storage services may also offer delta uploads – be sure you choose one that does if you’re using a TrueCrypt volume.
Use An App
BoxCryptor is an easy-to-use encryption solution. In spite of its name, you can use it with any cloud storage service, not just Dropbox. BoxCryptor creates a special subfolder in your cloud storage folder — in this folder, BoxCryptor stores encrypted versions of the files you add to a special BoxCryptor drive letter.
BoxCryptor also has mobile apps, allowing you to access your encrypted files on the go. The Android app supports Dropbox and Google Drive, with SkyDrive support on the way. The iOS app will also receive Google Drive and SkyDrive support in the future. The free version of BoxCryptor is limited to 2GB of encrypted files.
For more information, check out our full BoxCryptor walkthrough.
CloudFogger, which we’ve covered in the directory, and are other, competing services which work similarly.
Switch To An Encrypted Service
All the other options here are ways of grafting client-side encryption onto a cloud storage service that doesn’t natively support it. Instead, you could opt for a cloud storage service that includes client-side encryption. SpiderOak and Wuala are good options. These services encrypt and decrypt your data locally – the services themselves have no idea what data you’re storing; they couldn’t view it if they wanted to.
Check out our full walkthrough of SpiderOak for more information. It’s a bit more complicated to set up than Dropbox and similar services, but it offers more flexibility – for example, you can synchronize any folder on your computer.
Encrypt Individual Files
If this all seems a bit much for you, you can just encrypt a handful of important files with a utility on your computer. You’ll need the utility to decrypt and access your encrypted files in the future. We’ve covered a variety of ways to easily and quickly encrypt files in the past, including creating an encrypted archive file.
Set Up EncFS On Linux
EncFS is an open-source option for Linux users. It’s exactly what it sounds like – an encrypted file system. It works similarly to BoxCryptor (in fact, it inspired BoxCryptor) – EncFS creates a special folder that contains encrypted versionsof your files. EncFs transparently decrypts and provides access to these files in another folder. You work with your files in this folder, and EncFS stores the files in encrypted form in your cloud storage folder.
It’s a bit more complicated to set up, involving terminal commands. But, unlike the free version of BoxCryptor, it doesn’t limit the amount of files you can encrypt. We’ve got a guide to setting up EncFS on your Linux system, if you’re interested.
Which encryption solution do you prefer – or do you not store sensitive data in the cloud? Leave a comment and let us know.
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