How does database storage encryption handle data isolation in a multi-tenant environment?

Database storage encryption enhances data isolation in a multi-tenant environment by ensuring that each tenant's data is encrypted with unique keys or key hierarchies, preventing unauthorized access across tenants. Even if data is stored in shared infrastructure, encryption ensures that one tenant cannot read or manipulate another tenant's data, even with physical or logical access to the storage medium.

How it works:

1. Tenant-specific encryption keys: Each tenant’s data is encrypted with a dedicated key, often managed through a key management system (KMS). This ensures that even if data files are co-located, they remain inaccessible without the correct key.
2. Column-level or table-level encryption: Sensitive fields (e.g., personally identifiable information) can be encrypted separately, adding granularity to isolation.
3. Access control integration: Encryption keys are tied to tenant identities, so only authorized users or applications with the right permissions can decrypt and access the data.

Example:
In a cloud-based SaaS application hosting multiple clients, each client’s database tables or partitions are encrypted with unique keys. Even if a database administrator accesses the raw storage, they cannot read Client A’s data without Client A’s key.

Tencent Cloud services:
For such scenarios, Tencent Cloud offers Tencent Cloud Key Management Service (KMS) to manage encryption keys securely and TencentDB for MySQL/PostgreSQL with transparent data encryption (TDE) to encrypt data at rest. These services ensure multi-tenant data isolation while maintaining performance and compliance.