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The five services in this comparison are Sync.com, pCloud, Internxt, Proton Drive and Tresorit. They differ most in how broadly they apply client-side encryption: pCloud requires you to use its opt-in Crypto folder, while the comparison describes the other four as encrypting storage account-wide. That distinction matters more than the phrase “zero-knowledge” alone. The list reflects Cloudwards’ editorial selection, not a universal ranking; features and plan terms can change, so confirm them with each provider before choosing.
What zero-knowledge cloud storage means
In practical terms, zero-knowledge or client-side encryption means a file is encrypted on your device before upload, and you control the key used to decrypt it. Cloudwards uses “client-side encryption” and “zero-knowledge encryption” interchangeably in its comparison, but providers can apply encryption to different portions of an account. The label alone is not proof of a particular implementation or a security guarantee.
Check whether encryption covers the whole account by default or only files you deliberately place in a protected folder. Also consider how recovery works: if you alone control the decryption key, losing access to it may affect your ability to recover encrypted files. Encryption does not remove the need to secure your devices, account credentials and sharing settings.
How the five services differ
Sync.com
Sync says its storage uses end-to-end encryption and zero-knowledge authentication. Cloudwards describes client-side encryption across Sync storage and reports a 5 GB free plan; confirm the current capacity and terms with Sync before signing up. The comparison and Sync’s product pages describe sharing, backup, restore and collaboration features. Those vendor descriptions are not independent security testing.
#1 Best Overall
- Hardware encrypted drive
- Simple to use pin access. RPM-5400
- Administrator password feature
- Bus powered
- Utilizes Military Grade FIPS PUB 197 Validated Encryption Algorithm
pCloud
pCloud’s client-side encryption is an opt-in feature: its instructions describe enabling Encryption and putting files in a Crypto folder. Cloudwards says the free tier does not include client-side encryption. Do not assume that files in the ordinary pCloud account receive the same zero-knowledge protection as files placed in Crypto.
Internxt
Cloudwards describes Internxt as applying client-side encryption account-wide and reports a 1 GB free plan. Those technical and plan details are comparison-page claims; the material available for this overview did not establish them through an Internxt security page. Check Internxt’s current documentation and plan terms directly, especially if encryption scope or free capacity is decisive.
Rank #2
- Utilizes Military Grade FIPS PUB 197 Validated Encryption Algorithm
- Super fast USB 3.0 Connection - Data transfer speeds up to 10X faster than USB 2.0
- Software Free Design - With no admin rights needed
- Sealed from Physical Attacks by Tough Epoxy Coating
- Brute Force Self Destruct Feature
Proton Drive
Proton says files are end-to-end encrypted and describes encrypted sharing. The company also publishes audit reports and makes its apps and encryption libraries open source. Proton’s pricing page lists a 5 GB free plan with end-to-end encryption, while prices were not reliably available in the captured page. Proton identifies Switzerland as its base; that fact is separate from how encryption works and does not by itself establish a particular legal outcome.
Tresorit
Tresorit says files and relevant metadata are encrypted on users’ devices with unique keys that are not sent to its servers in unencrypted form. The company describes granular sharing controls and ISO 27001:2022 certification. For regulated or sensitive workflows, assess the plan, settings, agreements, jurisdiction and applicable obligations rather than treating a certification or product statement as proof of compliance.
Rank #3
- Slim durable design to help take your important files with you
- Vast capacities up to 6TB[1] to store your photos, videos, music, important documents and more
- Back up smarter with included device management software[2] with defense against ransomware
- Help secure your important files with password protection and hardware encryption
- 3-year limited warranty
Compare the details that affect your choice
Encryption scope
Start by identifying which files are encrypted client-side and whether you must take an extra step to protect them. The comparison describes Sync.com, Internxt, Proton Drive and Tresorit as covering the account, while pCloud’s Crypto folder is opt-in. Confirm this behavior in the current documentation and understand what happens to files outside any protected area.
Storage and plan terms
The free-plan capacities reported by Cloudwards are 5 GB for Sync.com, 1 GB for Internxt and 5 GB for Proton Drive. They are not a complete or independently verified comparison of current plans. Plan prices, storage ceilings and included features can change; check provider pricing pages for current paid capacity, billing periods, limits and conditions. No reliable current paid-price comparison is established here.
Rank #4
- Easily store and access 2TB to content on the go with the Seagate Portable Drive, a USB external hard drive
- Designed to work with Windows or Mac computers, this external hard drive makes backup a snap just drag and drop
- To get set up, connect the portable hard drive to a computer for automatic recognition no software required
- This USB drive provides plug and play simplicity with the included 18 inch USB 3.0 cable
- The available storage capacity may vary.
Sharing and collaboration
Encryption and sharing are related but distinct decisions. Sync.com, Proton Drive and Tresorit describe sharing or collaboration features; review each service’s current controls for recipient permissions, link access, password protection, expiration and revocation. Decide whether the recipient needs an account and whether a shared file remains encrypted in the way you expect. Do not infer a specific control from a general claim that a service supports secure sharing.
Devices and everyday workflows
Before moving files, confirm that the service supports the desktop, mobile and web clients you need, and check its current sync behavior. If your workflow depends on backup or restore, verify which files and versions those features cover. Sync describes backup and restore, but feature availability and behavior can vary by plan and platform; they were not exhaustively assessed for this comparison.
Jurisdiction and assurance
Location, audits, certifications and encryption design answer different questions. Proton identifies Switzerland as its base, and Tresorit describes Swiss-law handling and ISO certification. Those claims may be relevant to a location or assurance requirement, but they do not replace review of key handling, account recovery, contractual terms or the rules that apply to your situation. Provider security and compliance statements should be treated as vendor claims.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Choose according to your requirements
- For account-wide encryption as described by the comparison: consider Sync.com, Internxt, Proton Drive or Tresorit, then verify scope and recovery details in the provider’s current documentation.
- If you are considering pCloud: decide whether an opt-in Crypto folder fits your workflow, and check the plan requirements for that feature.
- If free capacity is important: use the reported capacities only as a starting point, then confirm the current free-plan limit and feature set with the provider.
- For frequent sharing or teamwork: compare the precise recipient controls and collaboration tools you need instead of relying on broad “secure sharing” language.
- For regulated information: review your organization’s obligations, the service agreement and configuration alongside any certification or jurisdiction claim.
Sources and current details
Cloudwards’ comparison provides the selection and reported free-plan figures: Best zero-knowledge cloud storage. Provider information is available from Sync.com, pCloud Encryption, Proton Drive security, Proton Drive pricing and Tresorit security. Check these pages for current terms; provider security descriptions are claims by the providers.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
