How do cloud providers handle data encryption?

Cloud providers handle data encryption through a combination of encryption in transit, encryption at rest, and key management services. Data in transit is protected using protocols like TLS (Transport Layer Security), which encrypts communication between user devices and cloud servers. For example, when you upload a file to AWS S3 or Azure Blob Storage, the data is encrypted during transmission using TLS. Data at rest is encrypted using algorithms like AES-256, applied to storage systems such as databases, disks, or backups. Providers like Google Cloud automatically encrypt stored data by default, often using keys managed by their internal systems unless configured otherwise. Key management services, such as AWS Key Management Service (KMS) or Azure Key Vault, allow developers to control encryption keys, including rotation and access policies.

Key management is a critical component. Cloud providers offer options for customers to manage their own encryption keys or rely on the provider’s managed keys. For instance, AWS KMS lets users create and control keys used to encrypt data in services like S3 or RDS, while Google Cloud’s Cloud KMS integrates with services like BigQuery. Some providers also support hardware security modules (HSMs)—physical devices that securely store keys—such as Google Cloud’s Cloud HSM. This ensures keys are protected against unauthorized access, even from the cloud provider’s staff. Developers must decide whether to use provider-managed keys (easier but less control) or customer-managed keys (more secure but requiring active management).

Additional layers include client-side encryption and confidential computing. Client-side encryption involves encrypting data before sending it to the cloud, as seen in tools like AWS Encryption SDK or Google’s Tink library. This ensures data is never exposed in plaintext to the cloud provider. Confidential computing, offered by Azure Confidential Computing or AWS Nitro Enclaves, encrypts data during processing in memory, protecting it even while in use. For example, a healthcare app could use Azure’s enclaves to process sensitive patient data without exposing it. Developers must evaluate these options based on compliance needs, performance, and the sensitivity of their data to choose the right encryption strategy.