Request Syntax Request Parameters Response Syntax Response Elements Errors See Also

RespondToAuthChallenge

Some API operations in a user pool generate a challenge, like a prompt for an MFA code, for device authentication that bypasses MFA, or for a custom authentication challenge. A RespondToAuthChallenge API request provides the answer to that challenge, like a code or a secure remote password (SRP). The parameters of a response to an authentication challenge vary with the type of challenge.

For more information about custom authentication challenges, see Custom authentication challenge Lambda triggers.

Note

Amazon Cognito doesn't evaluate AWS Identity and Access Management (IAM) policies in requests for this API operation. For this operation, you can't use IAM credentials to authorize requests, and you can't grant IAM permissions in policies. For more information about authorization models in Amazon Cognito, see Using the Amazon Cognito user pools API and user pool endpoints.

Note

This action might generate an SMS text message. Starting June 1, 2021, US telecom carriers require you to register an origination phone number before you can send SMS messages to US phone numbers. If you use SMS text messages in Amazon Cognito, you must register a phone number with Amazon Pinpoint. Amazon Cognito uses the registered number automatically. Otherwise, Amazon Cognito users who must receive SMS messages might not be able to sign up, activate their accounts, or sign in.

If you have never used SMS text messages with Amazon Cognito or any other AWS service, Amazon Simple Notification Service might place your account in the SMS sandbox. In sandbox mode , you can send messages only to verified phone numbers. After you test your app while in the sandbox environment, you can move out of the sandbox and into production. For more information, see SMS message settings for Amazon Cognito user pools in the Amazon Cognito Developer Guide.

Request Syntax


{
   "AnalyticsMetadata": { 
      "AnalyticsEndpointId": "string"
   },
   "ChallengeName": "string",
   "ChallengeResponses": { 
      "string" : "string" 
   },
   "ClientId": "string",
   "ClientMetadata": { 
      "string" : "string" 
   },
   "Session": "string",
   "UserContextData": { 
      "EncodedData": "string",
      "IpAddress": "string"
   }
}

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

The request accepts the following data in JSON format.

AnalyticsMetadata

The Amazon Pinpoint analytics metadata that contributes to your metrics for RespondToAuthChallenge calls.

Type: AnalyticsMetadataType object

Required: No

ChallengeName

The challenge name. For more information, see InitiateAuth.

ADMIN_NO_SRP_AUTH isn't a valid value.

Type: String

Required: Yes

ChallengeResponses

The responses to the challenge that you received in the previous request. Each challenge has its own required response parameters. The following examples are partial JSON request bodies that highlight challenge-response parameters.

Important

You must provide a SECRET_HASH parameter in all challenge responses to an app client that has a client secret.

SMS_MFA

"ChallengeName": "SMS_MFA", "ChallengeResponses": {"SMS_MFA_CODE": "[code]", "USERNAME": "[username]"}

EMAIL_OTP

"ChallengeName": "EMAIL_OTP", "ChallengeResponses": {"EMAIL_OTP_CODE": "[code]", "USERNAME": "[username]"}

PASSWORD_VERIFIER

This challenge response is part of the SRP flow. Amazon Cognito requires that your application respond to this challenge within a few seconds. When the response time exceeds this period, your user pool returns a NotAuthorizedException error.

"ChallengeName": "PASSWORD_VERIFIER", "ChallengeResponses": {"PASSWORD_CLAIM_SIGNATURE": "[claim_signature]", "PASSWORD_CLAIM_SECRET_BLOCK": "[secret_block]", "TIMESTAMP": [timestamp], "USERNAME": "[username]"}

Add "DEVICE_KEY" when you sign in with a remembered device.

CUSTOM_CHALLENGE

"ChallengeName": "CUSTOM_CHALLENGE", "ChallengeResponses": {"USERNAME": "[username]", "ANSWER": "[challenge_answer]"}

Add "DEVICE_KEY" when you sign in with a remembered device.

NEW_PASSWORD_REQUIRED

"ChallengeName": "NEW_PASSWORD_REQUIRED", "ChallengeResponses": {"NEW_PASSWORD": "[new_password]", "USERNAME": "[username]"}

To set any required attributes that InitiateAuth returned in an requiredAttributes parameter, add "userAttributes.[attribute_name]": "[attribute_value]". This parameter can also set values for writable attributes that aren't required by your user pool.

Note

In a NEW_PASSWORD_REQUIRED challenge response, you can't modify a required attribute that already has a value. In RespondToAuthChallenge, set a value for any keys that Amazon Cognito returned in the requiredAttributes parameter, then use the UpdateUserAttributes API operation to modify the value of any additional attributes.

SOFTWARE_TOKEN_MFA

"ChallengeName": "SOFTWARE_TOKEN_MFA", "ChallengeResponses": {"USERNAME": "[username]", "SOFTWARE_TOKEN_MFA_CODE": [authenticator_code]}

DEVICE_SRP_AUTH

"ChallengeName": "DEVICE_SRP_AUTH", "ChallengeResponses": {"USERNAME": "[username]", "DEVICE_KEY": "[device_key]", "SRP_A": "[srp_a]"}

DEVICE_PASSWORD_VERIFIER

"ChallengeName": "DEVICE_PASSWORD_VERIFIER", "ChallengeResponses": {"DEVICE_KEY": "[device_key]", "PASSWORD_CLAIM_SIGNATURE": "[claim_signature]", "PASSWORD_CLAIM_SECRET_BLOCK": "[secret_block]", "TIMESTAMP": [timestamp], "USERNAME": "[username]"}

MFA_SETUP

"ChallengeName": "MFA_SETUP", "ChallengeResponses": {"USERNAME": "[username]"}, "SESSION": "[Session ID from VerifySoftwareToken]"

SELECT_MFA_TYPE

"ChallengeName": "SELECT_MFA_TYPE", "ChallengeResponses": {"USERNAME": "[username]", "ANSWER": "[SMS_MFA or SOFTWARE_TOKEN_MFA]"}

For more information about SECRET_HASH, see Computing secret hash values. For information about DEVICE_KEY, see Working with user devices in your user pool.

Type: String to string map

Key Length Constraints: Minimum length of 0. Maximum length of 131072.

Value Length Constraints: Minimum length of 0. Maximum length of 131072.

Required: No

ClientId

The app client ID.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 128.

Pattern: [\w+]+

Required: Yes

ClientMetadata

A map of custom key-value pairs that you can provide as input for any custom workflows that this action triggers.

You create custom workflows by assigning AWS Lambda functions to user pool triggers. When you use the RespondToAuthChallenge API action, Amazon Cognito invokes any functions that are assigned to the following triggers: post authentication, pre token generation, define auth challenge, create auth challenge, and verify auth challenge. When Amazon Cognito invokes any of these functions, it passes a JSON payload, which the function receives as input. This payload contains a clientMetadata attribute, which provides the data that you assigned to the ClientMetadata parameter in your RespondToAuthChallenge request. In your function code in AWS Lambda, you can process the clientMetadata value to enhance your workflow for your specific needs.

For more information, see Customizing user pool Workflows with Lambda Triggers in the Amazon Cognito Developer Guide.

Note

When you use the ClientMetadata parameter, remember that Amazon Cognito won't do the following:

Store the ClientMetadata value. This data is available only to AWS Lambda triggers that are assigned to a user pool to support custom workflows. If your user pool configuration doesn't include triggers, the ClientMetadata parameter serves no purpose.
Validate the ClientMetadata value.
Encrypt the ClientMetadata value. Don't use Amazon Cognito to provide sensitive information.

Type: String to string map

Key Length Constraints: Minimum length of 0. Maximum length of 131072.

Value Length Constraints: Minimum length of 0. Maximum length of 131072.

Required: No

Session

The session that should be passed both ways in challenge-response calls to the service. If InitiateAuth or RespondToAuthChallenge API call determines that the caller must pass another challenge, they return a session with other challenge parameters. This session should be passed as it is to the next RespondToAuthChallenge API call.

Type: String

Length Constraints: Minimum length of 20. Maximum length of 2048.

Required: No

UserContextData

Contextual data about your user session, such as the device fingerprint, IP address, or location. Amazon Cognito advanced security evaluates the risk of an authentication event based on the context that your app generates and passes to Amazon Cognito when it makes API requests.

Type: UserContextDataType object

Required: No

Response Syntax


{
   "AuthenticationResult": { 
      "AccessToken": "string",
      "ExpiresIn": number,
      "IdToken": "string",
      "NewDeviceMetadata": { 
         "DeviceGroupKey": "string",
         "DeviceKey": "string"
      },
      "RefreshToken": "string",
      "TokenType": "string"
   },
   "ChallengeName": "string",
   "ChallengeParameters": { 
      "string" : "string" 
   },
   "Session": "string"
}

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

AuthenticationResult

The result returned by the server in response to the request to respond to the authentication challenge.

Type: AuthenticationResultType object

ChallengeName

The challenge name. For more information, see InitiateAuth.

Type: String

ChallengeParameters

The challenge parameters. For more information, see InitiateAuth.

Type: String to string map

Key Length Constraints: Minimum length of 0. Maximum length of 131072.

Value Length Constraints: Minimum length of 0. Maximum length of 131072.

Session

The session that should be passed both ways in challenge-response calls to the service. If the caller must pass another challenge, they return a session with other challenge parameters. This session should be passed as it is to the next RespondToAuthChallenge API call.

Type: String

Length Constraints: Minimum length of 20. Maximum length of 2048.

Errors

For information about the errors that are common to all actions, see Common Errors.

AliasExistsException

This exception is thrown when a user tries to confirm the account with an email address or phone number that has already been supplied as an alias for a different user profile. This exception indicates that an account with this email address or phone already exists in a user pool that you've configured to use email address or phone number as a sign-in alias.

HTTP Status Code: 400

CodeMismatchException

This exception is thrown if the provided code doesn't match what the server was expecting.

HTTP Status Code: 400

ExpiredCodeException

This exception is thrown if a code has expired.

HTTP Status Code: 400

ForbiddenException

This exception is thrown when AWS WAF doesn't allow your request based on a web ACL that's associated with your user pool.

HTTP Status Code: 400

InternalErrorException

This exception is thrown when Amazon Cognito encounters an internal error.

HTTP Status Code: 500

InvalidEmailRoleAccessPolicyException

This exception is thrown when Amazon Cognito isn't allowed to use your email identity. HTTP status code: 400.

HTTP Status Code: 400

InvalidLambdaResponseException

This exception is thrown when Amazon Cognito encounters an invalid AWS Lambda response.

HTTP Status Code: 400

InvalidParameterException

This exception is thrown when the Amazon Cognito service encounters an invalid parameter.

HTTP Status Code: 400

InvalidPasswordException

This exception is thrown when Amazon Cognito encounters an invalid password.

HTTP Status Code: 400

InvalidSmsRoleAccessPolicyException

This exception is returned when the role provided for SMS configuration doesn't have permission to publish using Amazon SNS.

HTTP Status Code: 400

InvalidSmsRoleTrustRelationshipException

This exception is thrown when the trust relationship is not valid for the role provided for SMS configuration. This can happen if you don't trust cognito-idp.amazonaws.com or the external ID provided in the role does not match what is provided in the SMS configuration for the user pool.

HTTP Status Code: 400

InvalidUserPoolConfigurationException

This exception is thrown when the user pool configuration is not valid.

HTTP Status Code: 400

MFAMethodNotFoundException

This exception is thrown when Amazon Cognito can't find a multi-factor authentication (MFA) method.

HTTP Status Code: 400

NotAuthorizedException

This exception is thrown when a user isn't authorized.

HTTP Status Code: 400

PasswordHistoryPolicyViolationException

The message returned when a user's new password matches a previous password and doesn't comply with the password-history policy.

HTTP Status Code: 400

PasswordResetRequiredException

This exception is thrown when a password reset is required.

HTTP Status Code: 400

ResourceNotFoundException

This exception is thrown when the Amazon Cognito service can't find the requested resource.

HTTP Status Code: 400

SoftwareTokenMFANotFoundException

This exception is thrown when the software token time-based one-time password (TOTP) multi-factor authentication (MFA) isn't activated for the user pool.

HTTP Status Code: 400

TooManyRequestsException

This exception is thrown when the user has made too many requests for a given operation.

HTTP Status Code: 400

UnexpectedLambdaException

This exception is thrown when Amazon Cognito encounters an unexpected exception with AWS Lambda.

HTTP Status Code: 400

UserLambdaValidationException

This exception is thrown when the Amazon Cognito service encounters a user validation exception with the AWS Lambda service.

HTTP Status Code: 400

UserNotConfirmedException

This exception is thrown when a user isn't confirmed successfully.

HTTP Status Code: 400

UserNotFoundException

This exception is thrown when a user isn't found.

HTTP Status Code: 400