BYOK (Bring Your Own Key)

Infrastructure
About 1 min read

A security method that protects data when using cloud or AI services by utilizing encryption keys directly generated and managed by the user, rather than the service provider's encryption keys.

Also known as
Customer Managed Key ManagementCMEKCustomer Managed Encryption Key

Detailed explanation

An essential technology for retaining security ownership over enterprise data or training data inputted into AI tools. While the service provider (SaaS) offers physical storage space, the keys to decrypt the data are controlled directly by the customer in their own Key Management System (KMS). This prevents even the service provider's administrators from unauthorized access to the data, and allows immediate cutoff of data access by revoking the keys if necessary. It serves as a crucial selection criterion when adopting AI in regulated industries such as finance and healthcare.

Why it matters in tool selection

It minimizes the risk of data leakage when sensitive internal corporate knowledge is utilized for AI training or RAG (Retrieval-Augmented Generation). In particular, even in the event of an infrastructure incident at a cloud provider, only the company holding the key can restore or read the data, ensuring complete data governance.

What to check

  • Check compatibility with currently used KMS (AWS KMS, Azure Key Vault, etc.)
  • Whether additional licensing costs are incurred due to changing the key management entity
  • The impact on AI service availability during key rotation and revocation
  • Whether key usage history can be monitored in real time through log analysis

Example

When a financial enterprise adopts Azure OpenAI, it encrypts banking-related text data by linking a hardware security module (HSM)-based key stored in its own Azure Key Vault instead of the default key managed by Microsoft.

Comparison of key management methods

BYOK (Customer-Managed Key)

The customer controls the keys in their own key management system, meaning even the service provider cannot read the data if the keys are revoked. Suitable for regulated industries.

Provider-Managed Key (Default)

The service manages the keys on behalf of the user, making implementation simple, but the control over data decryption authority remains with the provider.

Related terms

Air-gappedOn-premiseEnterpriseRole-Based Access Control (RBAC)