# How Amazon Cognito works with IAM
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Before you use IAM to manage access to Amazon Cognito, learn what IAM features are available to use with Amazon Cognito.






**IAM features you can use with Amazon Cognito**  

| IAM feature | Amazon Cognito support | 
| --- | --- | 
|  [Identity-based policies](#security_iam_service-with-iam-id-based-policies)  |   Yes  | 
|  [Resource-based policies](#security_iam_service-with-iam-resource-based-policies)  |   No   | 
|  [Policy actions](#security_iam_service-with-iam-id-based-policies-actions)  |   Yes  | 
|  [Policy resources](#security_iam_service-with-iam-id-based-policies-resources)  |   Yes  | 
|  [Policy condition keys](#security_iam_service-with-iam-id-based-policies-conditionkeys)  |   Yes  | 
|  [ACLs](#security_iam_service-with-iam-acls)  |   No   | 
|  [ABAC (tags in policies)](#security_iam_service-with-iam-tags)  |   Partial  | 
|  [Temporary credentials](#security_iam_service-with-iam-roles-tempcreds)  |   Yes  | 
|  [Principal permissions](#security_iam_service-with-iam-principal-permissions)  |   No   | 
|  [Service roles](#security_iam_service-with-iam-roles-service)  |   Yes  | 
|  [Service-linked roles](#security_iam_service-with-iam-roles-service-linked)  |   Yes  | 

To get a high-level view of how Amazon Cognito and other Amazon services work with most IAM features, see [Amazon services that work with IAM](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html) in the *IAM User Guide*.

## Identity-based policies for Amazon Cognito
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**Supports identity-based policies:** Yes

Identity-based policies are JSON permissions policy documents that you can attach to an identity, such as an IAM user, group of users, or role. These policies control what actions users and roles can perform, on which resources, and under what conditions. To learn how to create an identity-based policy, see [Define custom IAM permissions with customer managed policies](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_policies_create.html) in the *IAM User Guide*.

With IAM identity-based policies, you can specify allowed or denied actions and resources as well as the conditions under which actions are allowed or denied. To learn about all of the elements that you can use in a JSON policy, see [IAM JSON policy elements reference](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_policies_elements.html) in the *IAM User Guide*.

### Identity-based policy examples for Amazon Cognito
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To view examples of Amazon Cognito identity-based policies, see [Identity-based policy examples for Amazon Cognito](security_iam_id-based-policy-examples.md).

## Resource-based policies within Amazon Cognito
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**Supports resource-based policies:** No 

Resource-based policies are JSON policy documents that you attach to a resource. Examples of resource-based policies are IAM *role trust policies* and Amazon S3 *bucket policies*. In services that support resource-based policies, service administrators can use them to control access to a specific resource. For the resource where the policy is attached, the policy defines what actions a specified principal can perform on that resource and under what conditions. You must [specify a principal](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_policies_elements_principal.html) in a resource-based policy. Principals can include accounts, users, roles, federated users, or Amazon Web Services services.

To enable cross-account access, you can specify an entire account or IAM entities in another account as the principal in a resource-based policy. For more information, see [Cross account resource access in IAM](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_policies-cross-account-resource-access.html) in the *IAM User Guide*.

## Policy actions for Amazon Cognito
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**Supports policy actions:** Yes

Administrators can use Amazon JSON policies to specify who has access to what. That is, which **principal** can perform **actions** on what **resources**, and under what **conditions**.

The `Action` element of a JSON policy describes the actions that you can use to allow or deny access in a policy. Include actions in a policy to grant permissions to perform the associated operation.



To see a list of Amazon Cognito actions, see [Actions defined by Amazon Cognito](https://docs.amazonaws.cn/service-authorization/latest/reference/list_amazoncognitoidentity.html#amazoncognitoidentity-actions-as-permissions) in the *Service Authorization Reference*.

Policy actions in Amazon Cognito use the following prefix before the action:

```
cognito-identity
```

To specify multiple actions in a single statement, separate them with commas.

```
"Action": [
      "cognito-identity:action1",
      "cognito-identity:action2"
         ]
```

### Signed versus unsigned APIs
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When you sign Amazon Cognito API requests with Amazon credentials, you can restrict them in an Amazon Identity and Access Management (IAM) policy. API requests that you must sign with Amazon credentials include server-side sign-in with `AdminInitiateAuth`, and actions that create, view, or modify your Amazon Cognito resources like `UpdateUserPool`. For more information about signed API requests, see [Signing Amazon API requests](https://docs.amazonaws.cn/general/latest/gr/signing_aws_api_requests.html).

Because Amazon Cognito is a consumer identity product for apps that you want to make available to the public, you have access to the following unsigned APIs. Your app makes these API requests for your users and your prospective users. Some APIs require no prior authorization, like `InitiateAuth` to start a new authentication session. Some APIs use access tokens or session keys for authorization, like `VerifySoftwareToken` to complete MFA setup for a user that has an existing authenticated session. An unsigned, authorized Amazon Cognito user pools API supports a `Session` or `AccessToken` parameter in the request syntax as displayed in the [Amazon Cognito API Reference](https://docs.amazonaws.cn/cognito-user-identity-pools/latest/APIReference/Welcome.html). An unsigned Amazon Cognito Identity API supports an `IdentityId` parameter as displayed in the [Amazon Cognito Federated Identities API Reference](https://docs.amazonaws.cn/cognitoidentity/latest/APIReference/Welcome.html).

For more information about the authorization models and roles of Amazon Cognito user pools API operations, see [List of API operations grouped by authorization model](authentication-flows-public-server-side.md#user-pool-apis-auth-unauth).

**Amazon Cognito identity pools API operations**
+ `GetId`
+ `GetOpenIdToken`
+ `GetCredentialsForIdentity`
+ `UnlinkIdentity`

**Amazon Cognito user pools API operations**
+ `AssociateSoftwareToken`
+ `ChangePassword`
+ `ConfirmDevice`
+ `ConfirmForgotPassword`
+ `ConfirmSignUp`
+ `DeleteUser`
+ `DeleteUserAttributes`
+ `ForgetDevice`
+ `ForgotPassword`
+ `GetDevice`
+ `GetUser`
+ `GetUserAttributeVerificationCode`
+ `GlobalSignOut`
+ `InitiateAuth`
+ `ListDevices`
+ `ResendConfirmationCode`
+ `RespondToAuthChallenge`
+ `RevokeToken`
+ `SetUserMFAPreference`
+ `SetUserSettings`
+ `SignUp`
+ `UpdateAuthEventFeedback`
+ `UpdateDeviceStatus`
+ `UpdateUserAttributes`
+ `VerifySoftwareToken`
+ `VerifyUserAttribute`





To view examples of Amazon Cognito identity-based policies, see [Identity-based policy examples for Amazon Cognito](security_iam_id-based-policy-examples.md).

## Policy resources for Amazon Cognito
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**Supports policy resources:** Yes

Administrators can use Amazon JSON policies to specify who has access to what. That is, which **principal** can perform **actions** on what **resources**, and under what **conditions**.

The `Resource` JSON policy element specifies the object or objects to which the action applies. As a best practice, specify a resource using its [Amazon Resource Name (ARN)](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference-arns.html). For actions that don't support resource-level permissions, use a wildcard (\$1) to indicate that the statement applies to all resources.

```
"Resource": "*"
```

### Amazon resource names (ARNs)
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**ARNs for Amazon Cognito federated identities**

In Amazon Cognito identity pools (federated identities), it is possible to restrict an IAM user's access to a specific identity pool, using the Amazon Resource Name (ARN) format, as in the following example. For more information about ARNs, see [IAM identifiers](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_identifiers.html).

```
arn:aws:cognito-identity:REGION:ACCOUNT_ID:identitypool/IDENTITY_POOL_ID
```

**ARNs for Amazon Cognito Sync**

In Amazon Cognito Sync, customers can also restrict access by the identity pool ID, identity ID, and dataset name.

For APIs that operate on an identity pool, the identity pool ARN format is the same as for Amazon Cognito Federated Identities, except that the service name is `cognito-sync` instead of `cognito-identity`:

```
arn:aws:cognito-sync:REGION:ACCOUNT_ID:identitypool/IDENTITY_POOL_ID
```

For APIs that operate on a single identity, such as `RegisterDevice`, you can refer to the individual identity by the following ARN format:

```
arn:aws:cognito-sync:REGION:ACCOUNT_ID:identitypool/IDENTITY_POOL_ID/identity/IDENTITY_ID
```

For APIs that operate on datasets, such as `UpdateRecords` and `ListRecords`, you can refer to the individual dataset using the following ARN format:

```
arn:aws:cognito-sync:REGION:ACCOUNT_ID:identitypool/IDENTITY_POOL_ID/identity/IDENTITY_ID/dataset/DATASET_NAME
```

**ARNs for Amazon Cognito user pools**

For Amazon Cognito Your User Pools, it is possible to restrict a user's access to a specific user pool, using the following ARN format:

```
arn:aws:cognito-idp:REGION:ACCOUNT_ID:userpool/USER_POOL_ID
```

To see a list of Amazon Cognito resource types and their ARNs, see [Resources defined by Amazon Cognito](https://docs.amazonaws.cn/service-authorization/latest/reference/list_amazoncognitoidentity.html#amazoncognitoidentity-resources-for-iam-policies) in the *Service Authorization Reference*. To learn with which actions you can specify the ARN of each resource, see [Actions defined by Amazon Cognito](https://docs.amazonaws.cn/service-authorization/latest/reference/list_amazoncognitoidentity.html#amazoncognitoidentity-actions-as-permissions).





To view examples of Amazon Cognito identity-based policies, see [Identity-based policy examples for Amazon Cognito](security_iam_id-based-policy-examples.md).

## Policy condition keys for Amazon Cognito
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**Supports service-specific policy condition keys:** Yes

Administrators can use Amazon JSON policies to specify who has access to what. That is, which **principal** can perform **actions** on what **resources**, and under what **conditions**.

The `Condition` element specifies when statements execute based on defined criteria. You can create conditional expressions that use [condition operators](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_policies_elements_condition_operators.html), such as equals or less than, to match the condition in the policy with values in the request. To see all Amazon global condition keys, see [Amazon global condition context keys](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_policies_condition-keys.html) in the *IAM User Guide*.

To see a list of Amazon Cognito condition keys, see [Condition keys for Amazon Cognito](https://docs.amazonaws.cn/service-authorization/latest/reference/list_amazoncognitoidentity.html#amazoncognitoidentity-policy-keys) in the *Service Authorization Reference*. To learn with which actions and resources you can use a condition key, see [Actions defined by Amazon Cognito](https://docs.amazonaws.cn/service-authorization/latest/reference/list_amazoncognitoidentity.html#amazoncognitoidentity-actions-as-permissions).

To view examples of Amazon Cognito identity-based policies, see [Identity-based policy examples for Amazon Cognito](security_iam_id-based-policy-examples.md).

## Access control lists (ACLs) in Amazon Cognito
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**Supports ACLs:** No 

Access control lists (ACLs) control which principals (account members, users, or roles) have permissions to access a resource. ACLs are similar to resource-based policies, although they do not use the JSON policy document format.

## Attribute-based access control (ABAC) with Amazon Cognito
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**Supports ABAC (tags in policies):** Partial

Attribute-based access control (ABAC) is an authorization strategy that defines permissions based on attributes called tags. You can attach tags to IAM entities and Amazon resources, then design ABAC policies to allow operations when the principal's tag matches the tag on the resource.

To control access based on tags, you provide tag information in the [condition element](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_policies_elements_condition.html) of a policy using the `aws:ResourceTag/key-name`, `aws:RequestTag/key-name`, or `aws:TagKeys` condition keys.

If a service supports all three condition keys for every resource type, then the value is **Yes** for the service. If a service supports all three condition keys for only some resource types, then the value is **Partial**.

For more information about ABAC, see [Define permissions with ABAC authorization](https://docs.amazonaws.cn/IAM/latest/UserGuide/introduction_attribute-based-access-control.html) in the *IAM User Guide*. To view a tutorial with steps for setting up ABAC, see [Use attribute-based access control (ABAC)](https://docs.amazonaws.cn/IAM/latest/UserGuide/tutorial_attribute-based-access-control.html) in the *IAM User Guide*.

## Using temporary credentials with Amazon Cognito
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**Supports temporary credentials:** Yes

Temporary credentials provide short-term access to Amazon resources and are automatically created when you use federation or switch roles. Amazon recommends that you dynamically generate temporary credentials instead of using long-term access keys. For more information, see [Temporary security credentials in IAM](https://docs.amazonaws.cn/IAM/latest/UserGuide/id_credentials_temp.html) and [Amazon Web Services services that work with IAM](https://docs.amazonaws.cn/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html) in the *IAM User Guide*.

## Cross-service principal permissions for Amazon Cognito
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**Supports forward access sessions (FAS):** No 

 Forward access sessions (FAS) use the permissions of the principal calling an Amazon Web Services service, combined with the requesting Amazon Web Services service to make requests to downstream services. For policy details when making FAS requests, see [Forward access sessions](https://docs.amazonaws.cn/IAM/latest/UserGuide/access_forward_access_sessions.html). 

## Service roles for Amazon Cognito
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**Supports service roles:** Yes

 A service role is an [IAM role](https://docs.amazonaws.cn/IAM/latest/UserGuide/id_roles.html) that a service assumes to perform actions on your behalf. An IAM administrator can create, modify, and delete a service role from within IAM. For more information, see [Create a role to delegate permissions to an Amazon Web Services service](https://docs.amazonaws.cn/IAM/latest/UserGuide/id_roles_create_for-service.html) in the *IAM User Guide*. 

For details about Amazon Cognito service roles, see [Activate push synchronization](identity-pools.md#enable-push-synchronization) and [Implementing push synchronization](push-sync.md).

**Warning**  
Changing the permissions for a service role might break Amazon Cognito functionality. Edit service roles only when Amazon Cognito provides guidance to do so.

## Service-linked roles for Amazon Cognito
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**Supports service-linked roles:** Yes

 A service-linked role is a type of service role that is linked to an Amazon Web Services service. The service can assume the role to perform an action on your behalf. Service-linked roles appear in your Amazon Web Services account and are owned by the service. An IAM administrator can view, but not edit the permissions for service-linked roles. 

For details about creating or managing Amazon Cognito service-linked roles, see [Using service-linked roles for Amazon Cognito](using-service-linked-roles.md).