AWS Key Management Service vs AWS Secrets Manager: What are the differences?

Key Differences between AWS Key Management Service and AWS Secrets Manager

AWS Key Management Service (KMS) and AWS Secrets Manager are both services provided by Amazon Web Services (AWS) to securely manage keys and secrets, but they have some key differences.

1. Encryption vs Secret Management AWS Key Management Service (KMS) primarily focuses on encryption, providing a centralized service to manage the creation, rotation, and deletion of encryption keys used to encrypt and decrypt data. On the other hand, AWS Secrets Manager focuses on secret management, providing a secure and scalable solution to store, rotate, and retrieve secrets such as database credentials, API keys, and passwords.

2. Secret Rotation AWS Key Management Service (KMS) supports key rotation, enabling users to periodically rotate encryption keys to enhance security. However, it does not natively support secret rotation. AWS Secrets Manager, on the other hand, includes a built-in secret rotation feature, automatically rotating secrets in a secure manner without the need for manual intervention. This helps organizations maintain the highest level of security by regularly updating and rotating secrets.

3. Integration and Automation AWS Key Management Service (KMS) integrates well with other AWS services for encryption purposes, allowing users to encrypt data stored in various AWS resources. It provides encryption APIs that can be integrated into applications or used directly with other AWS services. On the contrary, AWS Secrets Manager is designed specifically for secrets management and provides a Secrets Manager API for accessing and managing secrets. It can be used to securely store, retrieve, and manage secrets for various applications and services.

4. Additional Functionality In addition to basic key and secret management, AWS Secrets Manager provides additional functionality to enhance security. It offers automatic database credential rotation for Amazon RDS databases, eliminating the need for manual rotation. It also integrates with AWS CloudFormation, allowing developers to securely retrieve secrets during infrastructure provisioning. AWS Key Management Service (KMS) mainly focuses on encryption-related tasks and does not offer these additional features.

5. Pricing Model AWS Key Management Service (KMS) has a pay-as-you-go pricing model, where users pay for the number of key requests made, key storage, and custom key store usage. On the other hand, AWS Secrets Manager has a similar pay-as-you-go pricing model, but the charges are based on the number of secrets stored, secrets retrieved, secrets rotated, and the amount of secret data transferred. The pricing models of both services differ due to their distinct functionalities and usage patterns.

6. Granularity of Access Control AWS Key Management Service (KMS) allows fine-grained control over access to encryption keys. Users can define key policies and use AWS Identity and Access Management (IAM) policies to control who can manage, use, and delete specific encryption keys. In contrast, AWS Secrets Manager provides a broader access control mechanism for managing secrets. Access can be controlled through resource-based policies and IAM policies, but the granularity is limited to the secret level rather than individual secrets.

In Summary, AWS Key Management Service (KMS) primarily focuses on encryption, while AWS Secrets Manager focuses on secret management and includes features like secret rotation, additional functionality for secure credential management, and different pricing models for their distinct use cases.