# Using Tag-Based Access Control
<a name="ecr-supported-iam-actions-tagging"></a>

The Amazon ECR `CreateRepository` API action enables you to specify tags when you create the repository. For more information, see [Tagging a private repository in Amazon ECR](ecr-using-tags.md).

To enable users to tag repositories on creation, they must have permissions to use the action that creates the resource (for example, `ecr:CreateRepository`). If tags are specified in the resource-creating action, Amazon performs additional authorization on the `ecr:CreateRepository` action to verify if users have permissions to create tags.

You can use tag-based access control through IAM policies. The following are examples.

The following policy would only allow a user to create or tag a repository as `key=environment,value=dev`.

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#### [ JSON ]

****  

```
{
    "Version":"2012-10-17",		 	 	 
    "Statement": [
        {
            "Sid": "AllowCreateTaggedRepository",
            "Effect": "Allow",
            "Action": [
                "ecr:CreateRepository"
            ],
            "Resource": "*",
            "Condition": {
                "StringEquals": {
                    "aws:RequestTag/environment": "dev"
                }
            }
        },
        {
            "Sid": "AllowTagRepository",
            "Effect": "Allow",
            "Action": [
                "ecr:TagResource"
            ],
            "Resource": "*",
            "Condition": {
                "StringEquals": {
                    "aws:RequestTag/environment": "dev"
                }
            }
        }
    ]
}
```

------

The following policy would allow a user to pull images from all repositories unless they were tagged as `key=environment,value=prod`.

------
#### [ JSON ]

****  

```
{
    "Version":"2012-10-17",		 	 	 
    "Statement": [{
            "Effect": "Allow",
            "Action": [
                "ecr:BatchGetImage",
                "ecr:GetDownloadUrlForLayer"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Deny",
            "Action": [
                "ecr:BatchGetImage",
                "ecr:GetDownloadUrlForLayer"
            ],
            "Resource": "*",
            "Condition": {
                "StringEquals": {
                    "ecr:ResourceTag/environment": "prod"
                }
            }
        }
    ]
}
```

------