Okay, so events like that are rare, but cloud storage provides an alternative (or additional) bullet-proof solution that’s immune to them.
For those who don’t know, ‘the cloud’ is tech speak for internet storage that’s accessed via special apps you install on your PC or mobile device. On a PC the cloud storage apps usually create a magical folder, the contents of which are automatically (and invisibly) synced with the cloud storage whenever you add new files or modify existing ones. You can install the client app on other computers and, once logged in, your files will sync there too.
'Because of the cost of cloud storage, dif cult decisions sometimes need to be made`
Alternatively, some dedicated cloud backup apps simply sync folders or types of file that you specify and scan periodically for changed files. Restoring data after a disaster is a matter of installing the app on a different computer and selecting the files or folders you wish to restore. Cloud storage is undoubtedly one of the greatest innovations of recent years, but a persistent concern is privacy. After all, you’re passing your files to a third party and have to trust they won’t peek at them. You also have to believe they’ve put in place sufficient protection against hackers – and in our post-Snowden world, government agencies fall into this category.
There are various solutions to this problem, but it’s a mistake to believe all cloud services are created equal. In you want true privacy and security, some thought needs to go into your choices, as we explain over the following pages.
Basic Backup
The most fuss-free way of using cloud storage to back up your files is to simply work within the cloud storage folder, essentially turning it into your User folder. That is, when you create files, you should save them to the Dropbox or Google Drive folder or copy existing files there. Most desktop apps like Microsoft Office or Adobe Photoshop let you change the default save location, so saving a cloud copy of each file can become something you don’t even think about.This way, your files will automatically be backed up in the cloud, as will any changes you make to them, and restoring them in the event of disaster involves simply installing the cloud storage client app on a different computer and logging in, which will create a synced clone of the folder.
In addition to backup, the benefit of this approach is that you have instant access to your files anywhere there’s an internet connection. Want to show somebody you’ve just met your holiday snaps that normally live on your PC? Well, now you can, and the major cloud services offer mobile apps to let you get at your files.
Dedicated cloud backup services take a different approach compared to basic cloud storage providers, in that their apps sit in the background and periodically back up certain folders or types of files, regardless of where they’re stored. Setup is usually automatic, although if you don’t use the usual User folders such as Music, Movies, My Pictures and so on, then you might need to delve into the settings to tell the app where to find your files.
Unlike with a backup disk attached to your PC, the goal of cloud storage and backup isn’t to clone your entire system. If nothing else, that would be prohibitively expensive because cloud storage is charged by the gigabyte. Instead, the goal is to back up your personal data, such as pictures, music, office files and so on.
Because of the cost of cloud storage, difficult decisions sometimes need to be made. For example, it might be cheaper to burn your MP3 collection to DVD-R discs for backup than rely on cloud storage. Or you might simply choose not to bother backing up your multimedia collection. After all, if they’re purchased through a service like iTunes or Google Play you’ll probably be able to download them afresh, and for free, should disaster strike. Just look in the previous purchases section of each service.
If you do decide to back up large multimedia files, the initial backup could take a while to complete. Most home internet services in the UK are asynchronous, which means that the upload speed is significantly slower than the download speed. For example, my ADSL service downloads at around 16Mbps, but uploads are limited to around 800Kbps.
Whichever method you choose for backing up – cloud storage or dedicated cloud backup – privacy should be a prime concern, and that means understanding what types of encryption are provided by the cloud storage provider.
Encrypted Backup
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| Like most cloud storage services, Dropbox encrypts your files on their servers but that doesn’t protect your files from them. |
To remove these possibilities, the data might be stored encrypted on the cloud server. In fact, this is the approach used by most cloud storage and backup services. Unfortunately, the encryption is usually controlled by the cloud storage provider, so they can still access your files by simply decrypting them whenever they want. This level of encryption does present a brick wall to any hacker that somehow gains access to the server, though.
'A DIY approach to encrypted cloud backup can be signi ficantly cheaper`
The best form of cloud storage is where providers have a ‘zero knowledge’ policy, which is to say the encryption takes place on your computer before the files are uploaded. As such, the cloud storage provider is simply unable to access the files, and to them the files appear to be gibberish. |
| Cloud backup apps like Spideroak promise ‘zero knowledge’, meaning they simply can’t view files you store with them |
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| A DIY approach with Amazon Glacier and CloudBerry Backup can remove you from the radar of hackers and provide even tighter security |
However, if a zero-knowledge approach is clearly the best, why don’t all cloud storage providers use it? The answer lies in convenience – for you as an end user and the cloud service provider itself.
One severe limitation of zero-knowledge cloud storage is that your account password becomes supremely important, because it’s used to create the encryption key that protects your files. If you forget the password, then your backed-up files are completely inaccessible to you or anybody else. Worst of all, people tend not to realize they’ve forgotten a password until they need to use it.
If the cloud backup service controls the encryption, then they’re able to offer niceties such as password resets should you forget your login details and technical support whereby they can dig into your file collection
More importantly for cloud storage providers, keeping control of encryption allows space to be saved on the server by only storing one version of a file, regardless of how many users upload it. This is called deduplication. If users Bill, Chris and Mike upload the same MP3 file, then only one copy of the file is stored, even though all four users appear to have their own copy. If the MP3 file is individually encrypted by each user, then it’s impossible for cloud service providers to know it’s the same file, meaning much more storage space is used. This is why zero-knowledge cloud services tend to be more expensive.
to fix errors. Equally, if files are encrypted by the user before uploading, then they simply can’t be shared with other users. Offering files for download from public web pages becomes impossible, as does collaborative working. These are key features of cloud services like Dropbox and Google Drive.
Zero Knowledge
For those who desire the best possible security, zero-knowledge encryption – sometimes referred to as personal encryption – appears to be the way to go. But even here there are caveats. Not all zero-knowledge services are the same. |
| BoxCryptor provides a layer of uncrackable encryption to popular cloud storage services like Dropbox and Google Drive |
'Importantly for cloud storage providers, keeping control of encryption allows space to be saved`
Unfortunately, this is a dangerous setup, because if your hard disk fails, then the encryption key stored on it will also be lost. Once that’s lost, there’s no way to decrypt the cloud backup data.Because of this risk, most cloud services offering personal encryption use a ‘secrets file’, which contains the encryption key, alongside other authenticating data. This resides on your computer’s hard disk and is itself encrypted using a password you supply. It’s also uploaded to the cloud server, along with your data, so it can be restored in future and subsequently unlocked using your password, to allow the decryption of all your files.
Although sensible, this approach provides a point of weakness, because should a hacker get hold of the secrets file, they can attempt to brute force its password – something that’s significantly easier than attempting to crack the actual encryption key. A brute force attack is where hackers try literally billions of guesses, generated automatically by a special program running on powerful computers.
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| Some cloud backup services like Cyphertite let you take control of your all-important encryption key, so nobody can hack it |
You can make the hacker’s job significantly harder by ensuring your cloud password is extremely strong – at least 20 characters long and random, including letters, numbers and symbols.
To protect against the admittedly unlikely eventuality of hackers getting hold of the secrets file, a handful of cloud storage services provide the option of not uploading it, thus providing the best possible security. In this instance, you should back up the secrets file to something like a USB memory stick (or perhaps two or even three sticks, to prevent against loss). Some providers even advocate printing it out, so it can be re-inputted by hand, should the need arise – despite the fact it’s usually several lines of user-unfriendly gibberish letters, numbers and symbols.
Choosing A Provider
The table in Picture provides an at-a-glance view of some major cloud services you might choose to go with. We’ve only included services that provide zero knowledge encryption, because we think that, in today’s world, this is a necessity. Unfortunately, there aren’t very many of these at present. Most offer free plans, so you can discover how the service works for you.Most cloud providers not only back up files but store older versions of your files. In other words, if you tweak a photo, save your changes but decide you’ve made a mistake, you can use your cloud storage to retrieve an earlier version. Older versions are usually stored for a limited time, although some storage providers hold them indefinitely.
Sync Yourself
A DIY approach to encrypted cloud backup can be significantly cheaper than services like Dropbox or Spideroak. The trick is to use online storage space that you ‘rent’ yourself, and use a dedicated client app on the PC to back up to it. The client encrypts files before uploading them.
Services product. With Glacier you pay for what you use, rather than via monthly or yearly subscription fees. Prices start from US$0.01 per gigabyte of space, per month. However, retrieving data in the event of a disaster also has a cost attached, with the cost dropping significantly if you retrieve data slowly over several hours.
'Most cloud providers not only back up files but store older versions of your fi les'
Files uploaded to Glacier are encrypted automatically and invisibly to the user, although this approach means Amazon holds the encryption key and can potentially access your data. Therefore, encrypting files before uploading is a necessity for full peace of mind. Apps like CloudBerry Desktop Backup (www.cloudberrylab.com/amazon-s3-cloud-desktop-backup.aspx) cost $29.99 and offer the same features as dedicated cloud backup apps, except they let you choose your destination, which can include Amazon Glacier. CloudBerry Desktop Backup also includes individual file encryption.
Before using apps like CloudBerry, you’ll need to sign up for Glacier, which will involve handing over credit card details and being issued an Access Key ID and Secret Access Key, which you’ll need to enter into the backup software.
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| Mega offers a similar service to Dropbox, except it offers zero-knowledge encryption, so it can’t snoop on your file |
A semi-DIY solution is to use any cloud storage service, regardless of whether it offers encryption, and encrypt files yourself before uploading using a third-party app like Boxcryptor (free from www.boxcryptor.com), which will automatically and invisibly encrypt files by creating a new virtual folder that you use instead of the main cloud storage folder. The cloud backup service then takes care of uploading in the background as usual.
If you regularly use two of more computers, such as a desktop and laptop, then a third free potential solution is to use BitTorrent Sync (www.bittorrent.com/sync). This works like Dropbox, in that the contents of a magical folder are automatically synced to other computers on which the software is installed, and on which a secret passphrase has been entered. However, BitTorrent Sync is purely peer-to-peer, which means syncing only occurs while both computers are up and running; there’s no central cloud storage. However, if you have an old PC or laptop that you don’t mind keeping running 24/7, then installing BitTorrent Sync on it, along with your everyday computers, makes for a very usable solution. A similar but slightly more hands-on technology is SparkleShare (sparkleshare.org).
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