End-to-end encrypted cloud storage, tools that encrypt files before they reach any cloud, self-hosting, private file transfer and backups.
Last reviewed · 19 entries
Cloud storage keeps copies of your files on someone else’s computers. With a mainstream service the provider holds the keys: it can scan your files, hand them over under a court order, expose them in a breach or lock you out of your account. Automated scanning has already led to innocent parents being reported to police over photos taken for a doctor (EFF, 2022).
End-to-end encrypted storage changes who can read your files: they are encrypted on your device before upload, and the provider stores data it cannot decrypt. It still knows your account, your IP address, how you pay and roughly how much you store and when. Encryption protects the contents, not your identity.
Almost every provider says your files are encrypted. The question that matters is who holds the key. If the provider does, it can decrypt your files whenever it wants or is ordered to. If only you do, it cannot.
Model
Who holds the keys
Can the provider read your files?
Examples
In transit and at rest
The provider
Yes. Encryption only protects against stolen disks and outsiders on the network
Google Drive, OneDrive, Dropbox, iCloud without Advanced Data Protection, Nextcloud server-side encryption
End-to-end (client-side)
You; files are encrypted on your device before upload
No, if the software is built correctly. Metadata remains visible
Proton Drive, Ente, Peergos, Filen, iCloud with Advanced Data Protection
Encrypt it yourself
You, with a separate tool
No. The provider only ever sees encrypted files
Cryptomator or rclone in front of any provider
Three kinds of “encrypted” storage
“Zero-knowledge” is a marketing term for end-to-end encryption. It is a claim about the software, not a guarantee: the provider writes the app that holds your keys, and a web app is downloaded fresh from its servers on every visit.
What end-to-end encryption does not hide
Your account. Email address, recovery details and payment records identify you. Use an alias address and pay privately where possible (see the Email guide and the crypto guide).
Your IP address. The provider sees where you connect from each time you sync. Use Tor or a VPN if that matters (VPN guide).
File sizes, counts and timestamps. Cryptomator states that it cannot hide the number of files, their sizes or their access and modification times. Even with Advanced Data Protection, Apple keeps the keys to file sizes, types and dates.
Sharing. A shared link usually carries the decryption key. Anyone who gets hold of the full link can open the file.
Your device. Malware on your phone or computer, or someone holding it unlocked, sees your files before encryption.
These providers encrypt your files, and in most cases the file names, on your device. All of them can still see who you are as a customer, so sign up with an alias address and pay privately if your identity matters. Laws on cash and cryptocurrency payments differ by country.
End-to-end encrypted file storage from the Swiss company behind Proton Mail. Encrypts file contents and names on your device, with open-source apps for most platforms.
Open-source, end-to-end encrypted backup for photos and videos, with a separate Locker app for documents and notes. The server code is public, so you can run your own.
Open-source, end-to-end encrypted storage, sync and sharing run by a non-profit. Designed so the server cannot see file names, sizes, folder structure or who you share with.
You do not have to trust a provider’s encryption at all. These tools encrypt files on your computer and hand only the encrypted result to whatever storage you use: a mainstream account, a cheap storage bucket, a friend’s server or an encrypted provider as a second layer. Changing provider later means moving a folder of encrypted files. The provider still sees your account, your IP address and the size and timing of uploads.
Creates an encrypted vault inside any synced folder, such as Dropbox, Google Drive, OneDrive or Nextcloud, and shows its contents as a normal drive while unlocked.
Platform Support
WindowsmacOSLinuxAndroidiOSOpen sourceNo account
Advantages
+Encrypts file contents and names and flattens the folder structure
+Free and open source on Windows, macOS and Linux
+Works with any provider that syncs a local folder
+No account needed
+Android licence and supporter certificate sold via ProxyStore (Monero, Bitcoin, cash)
+Cryptomator Hub for teams can be self-hosted (free for up to 5 seats)
Drawbacks
-Cannot hide file sizes, file counts or timestamps
-Write access on Android and iOS is a paid one-time purchase
-Last published third-party audit of its crypto libraries dates from 2017 (Cure53)
-No protection if other programs keep unencrypted copies of files you open
Running your own server takes the storage company out of the picture: you choose the hardware, the jurisdiction and who has access. In exchange you become the operator. You install updates, keep backups and fix things when they break, and a neglected server is easier to break into than a large provider. If the server is a rented virtual machine, the hosting company can read its disks, so encrypt there too or keep data on hardware you own (see the Server hosting guide). Ente and Peergos, above, can also be self-hosted.
Open-source platform you run on your own server for files, calendars, contacts and sharing. A good choice when you control the hardware; its optional end-to-end encryption is limited.
To pass a file to someone once, you do not need a cloud account. These tools encrypt the transfer end to end. With Send and Wormhole, the decryption key sits in the part of the link after #, which browsers do not send to the server, so anyone who sees the full link can open the file. Share links through an end-to-end encrypted messenger (Messaging guide), and remove hidden metadata such as GPS location from files first (Metadata guide).
Turns your computer into a temporary Tor onion service from which others download files with Tor Browser. Can also receive files, host a simple website and run a chat room.
Community-maintained fork of Mozilla’s discontinued Firefox Send. Encrypts a file in your browser and gives you a link that expires after a set time or number of downloads.
Most people’s files already sit in one of these, often through automatic phone photo backup. Apart from iCloud with Advanced Data Protection switched on, none of them encrypts your personal files end to end, so the company can scan them and must hand them over when legally ordered. If you need one for work, family sharing or free storage, keep sensitive files inside a Cryptomator vault.
With Advanced Data Protection (ADP) switched on, iCloud Drive, Photos and device backups are end-to-end encrypted. It is off by default, and new users in the UK cannot enable it.
February 2025: Apple withdrew ADP for new UK users after a UK government order under the Investigatory Powers Act. That order was reported dropped in August 2025; a second, UK-focused order followed in October 2025, which Apple has challenged at the Investigatory Powers Tribunal.
Platform Support
macOSiOSWeb
Advantages
+With ADP, iCloud Drive, Photos and backups are end-to-end encrypted
+Built into iPhone, iPad and Mac
+ADP available everywhere except to new UK users
Drawbacks
-ADP is off by default; without it Apple holds the keys to Drive, Photos and backups
-Even with ADP, Apple holds keys to file sizes, types, dates and checksums
-Shared albums and “anyone with the link” shares are not end-to-end encrypted
-Mail, contacts and calendars are never end-to-end encrypted
Google’s storage for files and photos, shared under one quota. Google holds the keys and scans content for child abuse material with hash matching and machine-learning classifiers.
Platform Support
WindowsmacOSAndroidiOSWeb
Advantages
+Free storage tier
+Convenient sharing and collaboration
Drawbacks
-No end-to-end encryption for personal accounts
-Client-side encryption only on some business and education Workspace editions
-Scanning flagged two fathers’ medical photos as abuse; Google refused to restore one account (2022)
Encryption protects your files from other people. Backups protect them from loss: a dead drive, a stolen laptop, ransomware, a provider that shuts down or suspends your account, or a forgotten password. With end-to-end encrypted storage a lost password can be final: the provider cannot reset your key, so without your recovery phrase the files are gone.
Sync is not backup. Sync services and Syncthing copy deletions, overwrites and ransomware-encrypted files to every device. Use a tool that keeps older versions.
Encrypt backups before they leave your machine.restic and BorgBackup are open-source tools that encrypt, deduplicate and version backups, so the backup server only stores ciphertext. rclone and Cryptomator, above, also work.
Keep one copy offline. An encrypted external drive that is unplugged most of the time survives account suspensions and ransomware. See the Encryption guide.
Test a restore. A backup you have never restored from is a guess.
Store recovery keys safely. Keep your vault passwords and recovery phrases in a password manager and on paper in a safe place (Password guide). Losing them means losing the data.
Check what uploads automatically. Phone photo apps and Windows can back up photos and folders to Google, Apple or Microsoft. Check those settings when you move to an encrypted service, or new copies keep arriving at the old one.
Delete what you leave behind. After moving, delete files from the old service and empty its trash. Deleted files may still be kept for a while under the provider’s retention rules.
Sign up and pay with care. Use an alias email address, skip the phone number where you can, and pay with cash or cryptocurrency where accepted. Keep pseudonymous accounts separate from your real identity (alting guide).
Protect the account. Use a unique password and app-based or hardware two-factor authentication. Anyone who logs in to your account can read your files, encrypted or not.
Strip metadata before sharing. Photos carry GPS coordinates and device details; documents carry author names. See the Metadata guide.
Manage share links. Set expiry dates and passwords, revoke links you no longer need, and remember that anyone holding a link can usually open the file.
Hide your IP address if it matters. Connect through Tor or a VPN when uploading anything that could identify you by location.
Make sure you can leave. Before committing, check that the service lets you export everything in a usable form, and export from time to time.