What is the most secure cloud storage? 4 secure clouds to consider

The most secure cloud storage systems are characterised by advanced threat detection, end-to-end encryption, and a secure login system (such as two-factor authentication). Our top 4 picks for most secure online storage systems are IONOS HiDrive, Sync, pCloud and Icedrive.

The 4 best cloud storage security options

Updated: February 2025

HiDrive Cloud Storage

IONOS HiDrive cloud storage is a secure online storage service that offers you flexible access to your data. In addition to a smartphone app, direct use of Git is also supported.

This cloud storage solution is an excellent choice when it comes to security. ISO 27001-certified servers ensure that your personal data is protected according to strict data protection guidelines. Login is also secure thanks to two-factor authentication. End-to-end encryption is also available in the Pro package, allowing you to encrypt your data with ease.

Sync

Sync is a cloud storage service that emphasises security and privacy, offering zero-knowledge encryption to ensure that only users can access their data, with even Sync.com unable to decrypt it. This feature is available across all packages, including the free ones. The service employs end-to-end encryption for shared links and SSL encryption during data transmission, and supports two-factor authentication (2FA) for enhanced account security.

Sync’s servers are located in Canada, a country known for its strong data privacy laws, and the company complies with regulations such as PIPEDA, FIPPA, and PHIPA. The platform is compatible with Windows and macOS for desktop, as well as iOS and Android for mobile devices, and integrates with Microsoft Office 365 for seamless document editing and collaboration. For users handling sensitive health information, Sync offers HIPAA compliance on its Pro Solo Professional and all Pro Teams packages, providing a HIPAA Business Associate Agreement upon request. In summary, Sync provides a user-friendly cloud storage solution with robust security measures, compliance with stringent data protection laws, and a range of features suitable for both individuals and businesses.

pCloud

pCloud is also up there with the safest cloud storage and offers a wide range of features. It offers zero-knowledge encryption through pCloud Crypto, but this comes at an additional cost. This feature ensures that only you can access your encrypted files—pCloud itself cannot decrypt them. To prove the strength of their encryption, pCloud launched the pCloud Encryption Hacking Challenge, offering $100,000 (around £80,000) to anyone who could break their security. To date, no one has succeeded.

When signing up, users can choose to store their data on servers in either Dallas, Texas (USA) or Luxembourg (EU). However, this selection cannot be changed later.

pCloud is available on macOS, Windows, and Linux, along with mobile apps for Android and iOS. Its combination of strong security, flexible storage options, and multi-platform support makes it a leading choice for privacy-conscious users.

Icedrive Cloud Storage

Icedrive is a cloud storage solution from Wales, known for its high cryptographic security. As one of the most secure cloud services, Icedrive employs the zero-knowledge principle, ensuring that only the user can decrypt their data.

The cloud service, also available as an app, offers 10 GB of free storage in its basic package. Users can also opt for one of the paid packages for additional storage and features.

Why is security an important factor in cloud storage?

Many users upload personal data to cloud storage systems. This often includes sensitive data such as photos or documents that should not fall into third-party hands. However, this is precisely the problem with many cloud providers. The data uploaded to the cloud is often unencrypted and can become the target of cyberattacks. Additionally, some cloud service providers do not prioritise data privacy. This issue becomes particularly concerning when data is stored in data centres outside of Europe, leading to potential shortfalls in data protection.

Security issues in cloud storage can also cause problems in a corporate context. When data from customers is uploaded to cloud-based storage solutions, a high level of security regarding data protection is essential for good customer relations.

What are common cloud security vulnerabilities?

The security of your data is influenced by both user cloud security best practices and the cloud service provider you choose.

Weak data protection laws

Sometimes, data can be accessed even when stored securely. It’s important to consider the data laws of the country where your cloud server is based. Since the UK is no longer part of the EU, it has its own data protection rules under the UK GDPR. However, many of its principles align with the EU’s GDPR.

In addition to Europe, Canada also maintains high standards when it comes to online data protection.

Data encryption

It’s difficult to find out how and whether most cloud providers encrypt your data in their cloud. Only a few cloud service providers offer end-to-end encryption or zero-knowledge encryption. If your data is not encrypted, it makes an easy target for attackers who are able to gain access to the cloud service’s data centres. This is why it can be worthwhile to encrypt your data yourself and then only upload it to the cloud in an encrypted state.

What makes cloud services especially secure?

With the most secure clouds, server location really does make a difference. Servers in Europe and Canada are particularly secure. In addition, an ISO 27001 certification guarantees a high standard of security in the data centre, ensuring your data is protected against attacks in the best possible way.

There are also providers that offer two-factor-authentication. With this type of authentication, you typically need to enter a time-based one-time code in addition to a password to access your cloud. This increases the security of the login process. For extra data security, cloud service providers sometimes even offer end-to-end data encryption. This type of protection is very effective, especially against outside attacks. Hackers would then not only have to bypass the protective measures the data centre has in place, but also decrypt your data.

Is a private cloud the most secure online storage?

A private cloud offers a particularly high level of protection against security risks. One advantage of having a cloud to yourself is that you alone have access to your data and can manage it. Additionally, the risk of external attacks is minimal compared to conventional cloud services. This is because cybercriminals are much more likely to view a cloud solution used by thousands of users as a more worthwhile target.

For companies and businesses in particular, a private cloud is the most secure cloud storage available. With the help of configurable firewall management, the security settings within the cloud can be adapted to the company’s requirements in the best possible way.