Finding the best cloud storage provider can look like a challenge, with all kinds of factors and issues to consider.
If you're a cloud storage newbie then we'll point you in the right direction by explaining what cloud storage is, how cloud storage benefits you and how to choose your perfect provider.
Seasoned techies can check out how we test cloud storage providers, or maybe browse the extensive list of 50+ cloud storage services we've reviewed to date.
If you're just looking for the top providers, we've ranked our top eight based on capacity, price, security, ease of use and more, and you can read our conclusions just a short scroll down the page.
In this list we've focused on quality paid packages for consumers and small businesses, but if that doesn't quite suit your needs, we also have guides to the Best free cloud storage, Best business cloud storage, Best cloud backup services and Best photo cloud storage.
Our best cloud storage deals, right now
1. IDrive is out top cloud storage provider (opens in new tab)
IDrive (opens in new tab), the cloud storage veteran, delivers tons of storage online for an incredibly small outlay, across a wide range of platforms. 10TB of storage for $3.98 (opens in new tab) for the first year is unmatched and so is the support for unlimited devices and the extensive file versioning system available.
2. pCloud provides a lifetime cloud storage subscription (opens in new tab)
pCloud (opens in new tab) is more expensive than the competition, but the one-off payment means that you won't have to worry about renewal fees that can be horrendously expensive. $350 for 10 years service is less than $3 per month.
Solo professionals can access Sync cloud storage for just $24 a month (dropping to $20 when billed annually). Teams, meanwhile, can access unlimited storage for $18 per user, per month (or just $15 if billed annually) - only with this exclusive deal.
What is cloud storage?
Cloud storage is a remote virtual space, usually in a data center, which you can access to save or retrieve files.
It’s important to know a cloud storage service can be trusted with your files, so most providers go to a lot of trouble to make sure they’re safe. They’ll upload and download files via a secure encrypted connection, for instance. Maximum security data centers ensure no unauthorized person gets access to their servers, and even if someone did break in, leading-edge encryption prevents an attacker viewing your data.
There are dozens of services which are powered by some form of cloud storage. You might see them described as online backup, cloud backup, online drives, file hosting and more, but essentially they’re still cloud storage with custom apps or web consoles to add some extra features.
You won’t have to look far to find your nearest cloud storage service, though, because there’s a very good chance you have access to one already. Facebook and Twitter provide free cloud storage when they allow users to store photos and videos on their servers, for instance, while even the most basic free Google account gets you 15GB of cloud storage space via the Google Drive app.
Which is the best cloud storage service?
If you're searching for the best cloud storage service, overall - then look no further than IDrive. It boasts an easy setup process, unlimited devices per account, and a paid version costing only $3.98 for 10TB for the first year. And it tops our lists for Best free cloud storage, Best cloud backup, and Best cloud storage for photos, too.
PCloud is another service vying for the title of Best cloud storage provider, thanks to features like its built-in players, powerful file sharing tools and great value lifetime plans.
Sync only does file syncing, as you'll guess from the name, but it does this very well and it's really easy to use. Backblaze is a comprehensive backup tool which offers unlimited storage, and right now you can get one Backblaze year for free when purchased with ExpressVPN. And if you're looking for simplicity, IceDrive gives you easy access to your cloud files for a very low starting price.
|Cloud storage services||Best plan||Online Storage|
|IDrive (opens in new tab)||$3.98 for first year||10TB|
|pCloud (opens in new tab)||$350 lifetime||2TB|
|Backblaze (opens in new tab)||$0 when purchasing ExpressVPN||Unlimited|
|IceDrive (opens in new tab)||$599 lifetime||5TB|
|NordLocker (opens in new tab)||$119.88/year||2TB|
Best cloud storage services of 2022
IDrive tops our best cloud storage charts with its appealing mix of easy-to-use apps, excellent backup tools, strong security and great value.
There are standout features everywhere. Lots of hardware to protect? Install it on as many devices as you like. Add or edit a file on one device, and it can be synced in real-time to all the others. And comprehensive backup tools allow protecting everything from individual files and folders, to creating a complete image of your device, for easy recovery after a disaster. (IDrive can even send you a physical drive with all your data, a big plus if you've a slow internet connection and it’ll take an age to download.)
Whatever you're doing, two-factor authentication protects your account, and end-to-end encryption ensures no-one will get the faintest sniff of your data. Highly configurable apps enable tweaking all kinds of low-level settings (bandwidth throttling, data verification), but if you're not the technical type, that's okay too: you can set up IDrive in moments and forget it's there, leave the service to do its job.
Standard prices are better than most, with personal plans starting at $59.62 at year ($79.50) for 5TB storage, rising to $74.62 ($99.50 on renewal) for 10TB, or $149.25 ($199 on renewal) for 10TB over two years. Right now there's also a spectacular deal offering 10TB for only $3.98 in the first year. And if you're still in any doubt, the company even offers a free-forever plan with 10GB space, perfect for trying out the service and making sure it's right for you.
Read our full IDrive cloud storage review and find out why it is the best cloud storage provider.
IDrive 10TB cloud storage -
$95.99 $3.98 for 1-year (opens in new tab)
IDrive, the secure cloud storage veteran, delivers tons of storage online for an incredibly small outlay. 10TB for $3.98 for the first year is unmatched, and so is the support for unlimited devices and the extensive file versioning system available.
Swiss-based pCloud is a comprehensive cloud storage service which offers a stack of essential backup, sharing and file management features.
Getting started is easy. Custom Windows, Mac, Linux, Android and iOS apps upload data using a secure TLS/SSL-encrypted connection, then copy your files to at least three separate pCloud servers for extra protection. You're able to sync key files across your devices (up to the recommended five per plan, anyway), and can freely share them with others.
We're not just talking plain download links, either (although they're an option.) PCloud allows users to create custom download pages with personalized messages for every shared file. You can build slideshows of shared images, and even play audio or video files directly from your storage space (no need to download them, first.)
All this looks costly at first glance, with pCloud asking £42.99 a year for just 500GB storage, or £85.99 for 2TB. But wait: choose pCloud's lifetime plans and you could get 500GB, forever, for a one-off £149, or 2TB for £299 (that won't even get you three years of protection with some provider’s 2TB accounts.)
Opting for the business plan adds a bunch of valuable extras: client-side encryption, central management of employees, secure file sharing, the ability to restore file versions up to 180 days old (up from 30 in the personal plan.) It's reasonably priced, too, at £7.24 a month per user for 1TB of storage space on the annual plan. And as with IDrive, a 10GB free plan gives you a risk-free way to check out the service.
Read our full pCloud Cloud Storage review.
pCloud 2TB lifetime cloud storage - $350 (opens in new tab)
At face value, you might think pCloud's offering is a little on the expensive side. However, a one-off payment will be cheaper in the long run plus, you can rest easy in the knowledge your data is secured by strong encryption and extensive redundancies.
As you'll probably guess from the name, Sync is a straightforward file syncing service: install the app across all your hardware, drop a file into the Sync folder on one device, and it'll quickly appear on all the others.
While this design limits Sync's backup abilities (you're only protecting what's in the Sync folder), it makes the apps exceptionally easy to use, and they still manage to beat many providers in other areas.
Versioning support allows you to restore file versions from up to the last 180 days, for instance (most providers stop at 30 days.) The mobile apps can automatically sync photos and videos as you take them. Sophisticated file sharing includes options to create read-only, password-protected or expiring links, set download limits and more.
Microsoft 365 users can open and edit Office documents directly from their Sync space. You're able to browse your files directly from Windows File Explorer or Mac Finder, making it easier to find what you need. And security features such as two-factor authentication and end-to-end encryption keep your data and transfers safe.
There are a host of business and team-friendly features. You can request files from multiple people, add comments to file sharing links, share folders with teams, view activity logs and manage everyone from a central console.
Prices are higher than most, with even the cheapest 2TB Solo Basic plan costing $96 a year, but if Sync's feature set matches your needs then it could be a smart choice. A 5GB free plan is available if you'd like to try it out.
Read our full Sync cloud storage review.
While some cloud storage services try to offer every possible file sharing and syncing feature, Backblaze takes a simpler approach: it handles personal and business backups, and that's it.
Fortunately, the company does this very well. All plans offer unlimited backup space, for instance, with no limit on file size. How many providers on this list can say that? (We'll save you looking: none.)
Worried about lengthy download times if you need to restore everything? No problem, the company can send you a hard drive with your data (up to 8TB.)
Backblaze is super-easy to use; just install the Windows or Mac apps (no mobile backups, unfortunately) and they'll automatically detect files as they're changed, then upload them to the cloud.
Smart security touches include two-factor verification to protect your account, while a private encryption key ensures no-one (not even Backblaze) can access your files online.
Pricing is fair at $70 a year per device for personal plans. There's no free tier, but a 15-day trial gives you a chance to check out the service for yourself.
If you're also looking for a VPN to protect yourself online, though, you can currently get Backblaze completely free for a year when you sign up to our #1 favorite, ExpressVPN (and you get three extra months of ExpressVPN protection, too.)
Read our full Backblaze review.
Get unlimited BackBlaze Cloud Backup FREE (opens in new tab)
BackBlaze is the only unlimited cloud storage service we recommend, offering unlimited bandwidth and file size. Sign up for the #1 rated VPN provider - ExpressVPN (opens in new tab) - for $6.67 per month and get your first year of BackBlaze completely free, a freebie worth $72.
Internxt is a security-focused provider which does way more than most to ensure that your files stay safe. End-to-end and zero-knowledge encryption prevents anyone accessing your data, and once your files are uploaded, they're split into parts and spread around a peer-to-peer network. Storing your data across multiple hosts not only hides it from hackers, it also means you're less likely to lose files through hardware failure or some other disaster.
Well-designed and intuitive apps mean uploading files can be as simple as a drag and drop. The ability to sync any folder keeps all your devices up-to-date, and you can easily share files via custom links.
Unusual bonus features include a password checker to identify weak passwords, and there's even a free virus scanner to identify and remove malware from your files.
Internxt also has its share of issues. It can't match the advanced features you'll find with OneDrive or Dropbox. Prices are higher than many at 41.88 Euros for a one-year, 200GB plan, or 107.88 Euros for 2TB. There is a 10GB free plan, but getting the full allowance is a hassle (you have to subscribe to the newsletter, invite four friends and more.)
Still, Internxt's security-first approach and quality apps give it a lot of appeal, and if that's what you're after, it more than deserves a place on your shortlist.
Read our full Internxt cloud storage review (opens in new tab).(opens in new tab)
UK-based cloud storage newcomer IceDrive may not yet have the power and polish of the top contenders, but the company already has more than enough nifty features to justify a very close look.
Windows users can browse their storage space from Explorer, for example, moving, renaming, opening and even editing files, just like working on a local drive.
A custom Windows, Mac and Linux app goes further, allowing you to browse files, preview documents, and stream your media files with a built-in player without having to download them first.
Smart service design uses multiple encryption technologies to keep your precious data safe from snoopers. The apps encrypt files using a private encryption key which never leaves your devices, for instance. Even if the world's best hackers managed to access IceDrive's servers, your data would be locked up and inaccessible.
A 10GB free plan gives you an easy way to get started, although with some restrictions (no client-side encryption, a 3GB/ day bandwidth limit.) IceDrive's subscriptions are so reasonably-priced, though, that we can forgive any free deficiencies. The Lite plan gives you 150GB for only $19.99 a year, for example. 1TB costs an annual $49.99, $5TB just $179.99, and lifetime options are priced from a one-off $99 for 150GB, to $599 for 5TB.
Read our full IceDrive review.
IceDrive 1TB lifetime cloud storage - $149 (opens in new tab)
One of the top options from IceDrive is the lifetime Pro deal, which gets you 1TB of storage – and 2TB of monthly bandwidth – on a permanent basis. Normally, it runs to $224, but you can pick up this plan for $149 now, which is a third off. If you prefer an annual Pro subscription, it’ll set you back $4.17 per month (meaning that in three years, you’ll pay the same as the lifetime cost).
The service is supremely easy to use. You begin by creating one or more lockers, which look like regular folders on your Windows and Mac device (Android and iOS devices can only use the more basic web interface.) Drag and drop files into a locker, and that's it, they're immediately updated to the cloud.
Super-tight security sees your files protected by industry-standard AES-256 and xChaCha20-Poly1305 encryption algorithms. Multi-factor authentication prevents attackers from hacking your account, and zero-knowledge architecture ensures only you can decrypt your files.
File sharing is relatively limited. You can do it, but there aren't many options, and your recipients must have a NordLocker account and be using the app.
A big introductory discount means prices look reasonable, but increase later. 500GB storage costs $38.28 for the first year, $69.98 on renewal; the 2TB plan is $95.88 in year one, but jumps to $179.88 after that. A free plan gives you 3GB storage to play with, a little disappointing when you often get 5-10GB elsewhere, but that's still enough to see how NordLocker works for you.
Read our full NordLocker review.
NordLocker Premium 2TB cloud storage - $9.99 per month (opens in new tab)
NordLocker only has one paid plan, which gives you 2TB of online storage. The good news is that it’s currently being offered at 50% off for the first year, so instead of forking out $19.99, you’ll pay $9.99 per month. There’s also a 30-day money-back guarantee if you’re not satisfied with the service initially.
Microsoft OneDrive isn't the most powerful or feature-packed cloud storage services around, but it more than handles the basics, and there's a lot to like here for anyone committed to the Microsoft world.
OneDrive is well integrated into Windows 10 and 11, for instance. You can work with the service from Explorer, dragging and dropping files to sync them with the cloud and any other devices using your Microsoft account. Microsoft 365 (opens in new tab) users who store their documents on OneDrive get auto saving to the cloud, and collaboration options including the ability to work on documents simultaneously with others, direct from the Office apps or web interface.
Microsoft hasn't forgotten other platforms, and OneDrive also has a straightforward Mac app, along with some very well-designed, intuitive Android and iOS apps. Xbox One gamers can use it to protect their game save files, and there's a capable web interface, too.
OneDrive's free plan looks a little disappointing, giving you a mere 5GB of storage. But you can upgrade to 100GB for only $19.99 a year (or $1.99 billed monthly.) And if you’ll make use of Microsoft Office, signing up for Microsoft 365 Personal not only gets you Outlook, Word, Excel and PowerPoint, but also boosts your OneDrive storage to a chunky 1TB each for up to 6 users.
Read our full Microsoft OneDrive review.
Microsoft 365 Family | $99.99 for 1-year (opens in new tab)
This is the best value for money offer from Microsoft. 365 Family costs only $99.99 per year and provides you with 6TB of secure cloud storage in all, spread across six separate users. Other than the apps included (Outlook, Word, Excel, Access, Publisher, OneNote and PowerPoint), you get AI-powered creative tools and 60 minutes of Skype calling per month.
Google Drive is a cloud storage service that's very easy to access. Got an Android device? It's built in. A Google account? Access it from your browser. There are official Mac and iOS apps, and a host of third-apps with Drive support.
Drive's integration with Google's other apps is a highlight. It doesn't just preview Office documents; Google's Sheets, Docs and Slides can create, edit and share cloud files with others, without ever downloading anything.
The free plan benefits from a market-leading 15GB storage, and there's more available with other apps (Google Photos specifically stores HD photos, for example).
Google Drive more than delivers on the cloud storage essentials, with easy access to data from apps and your browser, the ability to restore previous versions of files, and offline access for when you're not connected. But it's not all good news. Syncing isn't as simple as some competitors, and there's no end-to-end encryption; in theory, Google could see your files.
If you're not a Google fan, tying yourself so tightly into the company's ecosystem may not appeal. For everyone else, it offers a slick and powerful free service, and plenty of benefits if you upgrade. The $99.99 upgrade to Google One doesn't just get you 2TB of storage, but also includes 10% off Google Store purchases, access to Google experts, and even an Android and iOS VPN.
Read our full Google Drive review.
Google One (2TB) | $99 for 1-year (opens in new tab)
Google offers One as a membership, a quasi-lifetime commitment that's not unlike Amazon Prime. Although you get unlimited storage for your photos (terms and conditions apply), you "only" get 2TB to play with via Google Drive. You can share it among up to six members, and Google Experts are only a phone call away should you need them.
What to consider when choosing cloud storage services
Given the number of cloud storage providers on the market today - from tech giants like Google to smaller, more niche players - choosing the solution that’s right for you isn’t easy. One of the first things you’ll probably want to consider is cost. While the capital expenditure for cloud storage is usually very low (or nonexistent), the operational expenditure can add up when you factor in additional storage requirements and premium features. Be sure to check your cloud contract carefully to ensure you don’t receive an unexpectedly large bill.
Credentials around service and security standards are also key. Look for a cloud storage provider that can boast the certifications that promise an SLA you can rely on - and safeguards that protect your data. In addition, make sure your storage provider offers the scalability you need should you grow - and a flexible pricing model to accompany it. Perhaps the best thing to do when choosing a cloud storage provider is simply to shop around. There’s bound to be a solution that suits your needs - but don’t simply go with the first cloud provider you find.
How we tested the best cloud storage providers?
When we test a cloud storage provider, we look at the upload and download speeds of file transfers but this is a minor component of the overall rating as there are scores of other factors that affect your download or upload speeds that cannot be easily mitigated (contention rate, time of day, server load etc).
The other thing you’ll probably want to consider is cost. While the capital expenditure for cloud storage is usually very low (or nonexistent), the operational expenditure can add up when you factor in additional storage requirements and premium features. Be sure to check your cloud contract carefully to ensure you don’t receive an unexpectedly large bill.
Credentials around services and security standards are also key. Look for a cloud storage provider that can boast the certifications that promise an SLA you can rely on - and safeguards that protect your data. In addition, make sure your storage provider offers the scalability you need should you grow - and a flexible pricing model to accompany it.
Last but certainly not least is the level of support that a cloud storage service will provide to its customers, whether it's 24x7 over the phone or web-based only. Our reviews include all this and more details including usability, and platform compatibility, and compare each cloud storage service to similar rivals, across key features and pricing, so you can make an informed decision based on as much data as possible when it comes to the time when you will choose the best cloud storage provider for you.
For more detailed coverage, read: Cloud storage reviews: how we tested them (opens in new tab)
What is cloud storage and more:
What are the benefits of cloud storage?
Saving your data to the cloud protects you from all kinds of data disasters. Whether it's a dead hard drive, a lost laptop or a ransomware attack, having your files out of harm's way means you'll avoid a whole lot of pain.
Sharing files via the cloud is safer and easier than many alternatives. Send something by email or copy it to a USB key, and your data doesn't have much protection beyond wishful thinking ('no-one else has access to that email account, right?') The best cloud storage encrypts your files from the moment they leave your device, then gives you a range of secure ways to share them with others.
Many providers allow you to access files directly from your storage, without downloading them first. You might be able to stream a huge video from the cloud, for instance. You can often collaborate on files with others, perhaps with two people editing a document at the time.
Storing files in the cloud gives them real protection from damage, too. Accidentally deleted something? You'll usually find it in the Recycle Bin. Made a big mistake in the last few edits? You can often restore any previous version of the document from the last 30 days, and sometimes more - a real life-saver.
Where is data stored in the cloud?
The actual location of your files is usually in a data center somewhere, in a server, on a hard drive or solid-state drive. But bear in mind that there are providers that allow you to store files on tape drives and even on other people's computers using a technology similar to bit-torrent.
How does cloud storage work?
Believe it or not, the concept of cloud storage has been around for a long, long time. Amazon popularized the concept with its S3 (Simple Storage Service) launched in 2006 but the ability to upload and save files remotely on a service provider's disk drive can be traced back to 1983's Compuserve offer.
At the end of the day, you are simply using someone else's resources (part of whole of a hard drive, a solid state drive, or even tape) to store your information.
That resource is usually located in a server housed in a data center (but not always) alongside potentially hundreds of others. The process is done over the internet over a secure connection via a dedicated app or via a web browser.
Almost everyone who has a smartphone or an email address has a cloud storage account of some sort. One might even consider Facebook to offer a limited version of cloud storage to its members as videos and photos can be uploaded free of charge to its servers.
How to choose the best cloud storage service?
Finding your perfect cloud storage solution starts by thinking about your needs. What are you hoping the service will do?
If your goal is to protect all your data from harm, then look for a service with solid backup tools and the ability to access your files from anywhere.
If you'd like to share a group of files - photos, say - across multiple devices, then you'll need quick and easy syncing abilities.
If you're more interested in sharing individual files or folders with others, look for a platform which supports password-protected or time-limited links, anything that helps you stay more secure. Businesses will benefit from collaboration tools, too, allowing users to work on files together, add comments and more.
Pay attention to the figures. Most cloud storage keeps previous versions of your files for up to 30 days, for instance, but that's not always the case. If your provider says it supports 'versioning', that's good, but check the details, see how it really compares to the competition.
You'll want to consider a provider's cost and capacity, too, but be careful. Don't simply opt for a high-capacity plan just because it seeks better value: think about whether you really need that much space. And when it comes to price, browse the small print, look out for hidden charges or fees which jump on renewal, make sure you know exactly what you're getting.
Free vs Paid cloud storage: what you need to know
If your backup budget is low (or non-existent) then opting for free cloud storage might appeal, but is it the right choice for you?
Capacities are often very low (NordLocker's free plan has just 3GB), which is likely to rule out free plans for any heavy-duty tasks. Some free options may have other limits, or leave out important features from the paid plans. IceDrive's 10GB plan looks generous, for instance, but you can only use 3GB bandwidth a day, and there's no client-side encryption.
These may not be deal-breaking issues, at least if your needs are simple, and you can do better with a little work. Signing up with one provider doesn't mean you can't use another, for instance: set up IDrive for one task, Google and OneDrive for a couple of others, and suddenly you've 30GB to play with.
Free plans aren't only useful for bargain-hunters, though. However much you've got to spend, the real advantage of a free plan is it gives you time to try out different platforms before you commit.
How we test for the best cloud storage services
We begin our cloud storage reviews with a close inspection of the service's key features. How much storage space do you get? How many devices does the plan support? How secure are your data transfers, and exactly how much is all this to cost?
Many providers sell themselves on their own custom features - clever photo and media management tools, smarter and more secure ways to share files - and we drill down into the details of everything a provider offers.
There's more to a great cloud storage provider than the length of their feature list, though. That's why we also take the time to try out the service apps and web interface, find out how easy they are to use, and run our own comprehensive speed tests to check performance.
Benchmarks complete, we then drill down into the data, compare all the features and figures, and identify just where each provider ranks in our best cloud storage service charts.
What cloud storage have you reviewed?
As of March 2022, we've reviewed the following cloud storage providers
- IDrive Photos
- Microsoft OneDrive
- Google Drive
- Amazon Drive
- Amazon Photos
- Apple iCloud cloud storage
- Zoho WorkDrive cloud storage
- Ionos HiDrive
- SOS Online Backup
- WD Upthere
- Hetzner storage box
- Data deposit box
- G Cloud Unlimited cloud storage
- Internxt cloud storage
- 500px cloud storage
- Gladinet CentreStack
- AOMEI Multcloud cloud storage
- Rewind cloud storage
- Arq cloud storage
- IDrive e2
- Backblaze B2
Where did cloud storage come from?
Amazon is widely credited with launching the first true cloud storage. Simple Storage Service or S3 was unveiled in March 2006, almost 16 years ago. The actual term Cloud Storage predates it by more than 100 years. The earliest mention of Cloud Storage can be found in an 1896 book with a title that seems to come straight from the Marvel Cinematic Universe, The Mystery of the White Snake: A Legend of Thunder Peak Tower. 1896 was the year the modern Olympic games were revived in Athens; it’s that old.
Cloud storage jargon buster
Baffled by cloud-storage techno-speak? We've got the key terms you need to know.
AES-256: one of the strongest encryption algorithms around, AES-256 is often used to protect cloud storage and ensure no-one else can access your data.
At-rest encryption: encrypts your data while stored on a device, protecting it from snoopers. See In-transit encryption.
Cloud: servers that are accessed over the internet, along with the software, databases, computing resources and services they offer.
Continuous data backup: a clever technology which automates backups by looking out for new and changed files, and uploading them as soon as they appear.
Data center: one or more physical facilities which house networked computers and the resources necessary to run, access and manage them: storage systems, routers, firewalls and more.
Egress: the transfer of data from a network to an external location, such as downloading a file from a cloud storage account. (See Ingress.)
End-to-end encryption: a method of communicating data which ensures no-one but the sender and receiver can read or modify it. In cloud storage terms, it means your files can't be intercepted and accessed by anyone, even your provider.
Ingress: the transfer of data into a network, such as uploading a file to a cloud storage account. (See Egress.)
In-transit encryption: encrypts your data before transmission to another computer, and decrypts it at the destination. Even if an attacker can intercept your communications, they won't be able to read your files. (See At-rest encryption.)
Private cloud: a cloud computing environment which offers services to a single business only. A business might use its own private cloud storage to ensure no other company gets to handle its data, for instance, improving security. (See Public cloud.)
Private encryption key: a method of encryption which means only you can access your encrypted files. This guarantees your security, but is also a little risky, because if you forget your password, the provider can't help you recover it, and your data is effectively lost.
Public cloud: a network of computers which offers cloud services to the public via the internet. Google, Microsoft and Amazon are examples of public cloud providers. (See Private cloud.)
S3: A fast flexible cloud storage type invented by Amazon and used by major companies like Netflix, reddit, Ancestry and more.
Sync: the process of keeping a set of files up-to-date across two or more devices. Edit a file on one of your devices, for instance, and a cloud storage service which supports syncing will quickly upload the new version to all the others.
Two-factor authentication: a technology which requires you to enter an extra piece of information (beyond just a username and password) when logging into a web account: a pin sent by email or SMS, a fingerprint, a response to an authenticator app. It's an extra login hassle, but also makes it much more difficult for anyone to hack your account. Sometimes called 2FA or two-step authentication.
Versioning: the ability to keep multiple versions of a file in your cloud storage area. Accidentally delete something important in a document last Tuesday, and even if you've updated the file several times, you may still be able to recover the previous version.
Zero-knowledge encryption: a guarantee that no-one else, not even your cloud provider, has the password necessary to protect your data. That's great for security, but beware: if you forget your password, the provider can't remind you, and your files will be locked away forever.