Today, almost every one of us stores information in the cloud in one way or another. It can be photos, documents, work files, correspondence or even medical data. We entrust this data to third-party companies, which means we take risks. After all, hacker attacks, leaks, or even mistakes by the cloud provider’s employees can lead to data falling into the hands of outsiders. That’s where encryption comes into play – a technology that turns data into an incomprehensible set of characters and protects it from unauthorized access.
What is encryption in the cloud?
Encryption is a method of converting data from a normal readable form to an encrypted sequence of characters using a special algorithm and a key. Only the owner of the key can decrypt such information and return it to its original state. If an intruder gains access to encrypted files without the key, he or she will see only “digital noise” that is of no use.
When is encryption used?
- At rest – Data is encrypted on the disks where it is stored.
- In transit – information is protected during transmission between server and client.
- In use – when data is processed in memory, more sophisticated approaches like confidential computing are used.
Thus, encryption accompanies data at all stages of its lifecycle.
Cloud encryption models
- Server-side encryption
Here it’s simple: the cloud provider encrypts your files itself on the server side. This is convenient because you don’t have to configure anything. However, there is a nuance: keys are often also stored by the provider. This means you need to trust that they are protecting the keys properly and not misusing them.
- Client-side encryption
In this case, you encrypt your data before it is even uploaded to the cloud. Only you keep the keys. Even the provider itself cannot access the content. The disadvantage is that there is a little more configuration and key management is entirely up to you.
- End-to-end encryption
This is an option where encryption and decryption only happens at the end users. A great example is messengers like Signal or WhatsApp. Even the service provider doesn’t have access to the content.
- Bring Your Own Key (BYOK) or Bring Your Own Encryption (BYOE)
Some companies prefer complete control. They use their own encryption systems and only store encrypted data in the cloud. This approach requires a competent internal IT infrastructure, but gives maximum transparency and independence.
The technologies that cloud encryption relies on
Cloud data encryption is not just a single mechanism but a combination of well-established cryptographic techniques and innovative approaches. To understand how it ensures confidentiality and integrity, it’s important to look at the core technologies that form the foundation of secure cloud environments.
Symmetric and asymmetric encryption
Symmetric encryption uses the same key to encrypt and decrypt data, which provides high-speed processing and is suitable for large amounts of data, such as with AES-256. Asymmetric, on the contrary, is based on a pair of keys – public for encryption and private for decryption; this method is slower, but provides a more secure key transfer. In practice, the hybrid approach, which combines the advantages of both methods, is considered the most effective.
Envelope encryption
This method is widely used in cloud services. The data is first encrypted with a symmetric key (Data Encryption Key), after which the key itself is further protected by another key, the so-called Key Encryption Key. This approach simplifies key administration and significantly increases the security level of the system.
Confidential Computing
This technology solves an important problem: how to protect data while it is being processed. The data is processed inside an isolated and protected environment where neither the administrator nor the intruder has access. This approach is increasingly being used in medical and financial services.
Homomorphic encryption
This is one of the most advanced methods of data protection. What makes it special is that you can perform calculations directly on the encrypted information without revealing its contents. For example, you can send encrypted medical studies to the cloud, and the system will analyze and return the results without knowing what data it processed.
What’s all this for?
Cloud encryption may seem like a complex technical process, but its importance goes far beyond theory. It has a direct impact on the security of businesses and private users, protecting data from intruders and helping to meet modern standards.
- Privacy
If the data is encrypted, even if leaked, it will not be useful to an attacker.
- Legal compliance
Many industries are regulated by data protection laws – GDPR in Europe, HIPAA in US healthcare, PCI DSS in payments. Encryption helps companies comply with these requirements and avoid fines.
- Reducing the impact of attacks
Imagine a server with your files is stolen. If the data is encrypted, the attacker has no way to exploit it.
- Scalability and flexibility
Cloud services allow you to automatically scale your protection as your data grows. You don’t need to buy additional hardware or manually configure hundreds of servers.
Practical tips for companies and users
Understanding encryption is only half the battle. For data protection to really work, it is important to apply the technology correctly in practice and take into account the nuances that are often overlooked by both companies and individual users.
- Determine what data needs to be encrypted. Not all data is equally valuable. Personal information, trade secrets, and finances come first. It’s also a good idea to categorize information and assign criticality levels so that security resources are allocated wisely.
- Choose proven algorithms. It is best to use modern and recognized algorithms, such as AES-256 for storage and TLS for transmission. Keep up with updates in cryptography, as outdated algorithms can become vulnerable over time.
- Manage keys wisely. Keys are the weakest point of any encryption system. Use key managers (KMS), update keys regularly, and restrict access to keys. Consider using hardware security modules (HSMs) that provide an additional layer of key protection.
- Add an extra layer – confidential computing When it comes to truly critical data (e.g., medical records), consider implementing trusted execution environment technologies. This approach minimizes risk even if your operating system or cloud provider is compromised.
- Consider homomorphic encryption. It may still be expensive and resource-intensive, but it’s the future. This technology is especially relevant for industries where it is important to analyze large amounts of sensitive data, such as medicine and finance.