# Using service-linked roles for AWS KMS
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AWS Key Management Service uses AWS Identity and Access Management (IAM)[ service-linked roles](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_terms-and-concepts.html#iam-term-service-linked-role). A service-linked role is a unique type of IAM role that is linked directly to AWS KMS. Service-linked roles are defined by AWS KMS and include all the permissions that the service requires to call other AWS services on your behalf. 

A service-linked role makes setting up AWS KMS easier because you don’t have to manually add the necessary permissions. AWS KMS defines the permissions of its service-linked roles, and unless defined otherwise, only AWS KMS can assume its roles. The defined permissions include the trust policy and the permissions policy, and that permissions policy cannot be attached to any other IAM entity.

You can delete a service-linked role only after first deleting the related resources. This protects your AWS KMS resources because you can't inadvertently remove permission to access the resources.

For information about other services that support service-linked roles, see [AWS Services That Work with IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html) and look for the services that have **Yes **in the **Service-Linked Role** column. Choose a **Yes** with a link to view the service-linked role documentation for that service.

To view details about updates to the service-linked roles discussed in this topic, see [AWS KMS updates to AWS managed policies](security-iam-awsmanpol.md#security-iam-awsmanpol-updates).

**Topics**
+ [Authorizing AWS KMS to manage AWS CloudHSM and Amazon EC2 resources](authorize-kms.md)
+ [Authorizing AWS KMS to synchronize multi-Region keys](multi-region-auth-slr.md)