importKeyMaterial method

Future<ImportKeyMaterialResponse> importKeyMaterial({
  1. required Uint8List encryptedKeyMaterial,
  2. required Uint8List importToken,
  3. required String keyId,
  4. ExpirationModelType? expirationModel,
  5. ImportType? importType,
  6. String? keyMaterialDescription,
  7. String? keyMaterialId,
  8. DateTime? validTo,
})

Imports or reimports key material into an existing KMS key that was created without key material. You can also use this operation to set or update the expiration model and expiration date of the imported key material.

By default, KMS creates KMS keys with key material that it generates. You can also generate and import your own key material. For more information about importing key material, see Importing key material.

For asymmetric and HMAC keys, you cannot change the key material after the initial import. You can import multiple key materials into symmetric encryption keys and rotate the key material on demand using RotateKeyOnDemand.

You can import new key materials into multi-Region symmetric encryption keys. To do so, you must import the new key material into the primary Region key. Then you can import the same key materials into the replica Region keys. You cannot directly import new key material into the replica Region keys.

To import new key material for a multi-Region symmetric key, you’ll need to complete the following:

  1. Call ImportKeyMaterial on the primary Region key with the ImportTypeset to NEW_KEY_MATERIAL.
  2. Call ImportKeyMaterial on the replica Region key with the ImportType set to EXISTING_KEY_MATERIAL using the same key material imported to the primary Region key. You must do this for every replica Region key before you can perform the RotateKeyOnDemand operation on the primary Region key.
After you import key material, you can reimport the same key material into that KMS key or, if the key supports on-demand rotation, import new key material. You can use the ImportType parameter to indicate whether you are importing new key material or re-importing previously imported key material. You might reimport key material to replace key material that expired or key material that you deleted. You might also reimport key material to change the expiration model or expiration date of the key material.

Each time you import key material into KMS, you can determine whether (ExpirationModel) and when (ValidTo) the key material expires. To change the expiration of your key material, you must import it again, either by calling ImportKeyMaterial or using the import features of the KMS console.

Before you call ImportKeyMaterial, complete these steps:

  • Create or identify a KMS key with EXTERNAL origin, which indicates that the KMS key is designed for imported key material.

    To create a new KMS key for imported key material, call the CreateKey operation with an Origin value of EXTERNAL. You can create a symmetric encryption KMS key, HMAC KMS key, asymmetric encryption KMS key, asymmetric key agreement key, or asymmetric signing KMS key. You can also import key material into a multi-Region key of any supported type. However, you can't import key material into a KMS key in a custom key store.

  • Call the GetParametersForImport operation to get a public key and import token set for importing key material.
  • Use the public key in the GetParametersForImport response to encrypt your key material.
Then, in an ImportKeyMaterial request, you submit your encrypted key material and import token. When calling this operation, you must specify the following values:
  • The key ID or key ARN of the KMS key to associate with the imported key material. Its Origin must be EXTERNAL and its KeyState must be PendingImport or Enabled. You cannot perform this operation on a KMS key in a custom key store, or on a KMS key in a different Amazon Web Services account. To get the Origin and KeyState of a KMS key, call DescribeKey.
  • The encrypted key material.
  • The import token that GetParametersForImport returned. You must use a public key and token from the same GetParametersForImport response.
  • Whether the key material expires (ExpirationModel) and, if so, when (ValidTo). For help with this choice, see Setting an expiration time in the Key Management Service Developer Guide.

    If you set an expiration date, KMS deletes the key material from the KMS key on the specified date, making the KMS key unusable. To use the KMS key in cryptographic operations again, you must reimport the same key material. However, you can delete and reimport the key material at any time, including before the key material expires. Each time you reimport, you can eliminate or reset the expiration time.

When this operation is successful, the state of the KMS key changes to Enabled, and you can use the KMS key in cryptographic operations. For symmetric encryption keys, you will need to import all of the key materials associated with the KMS key to change its state to Enabled. Use the ListKeyRotations operation to list the ID and import state of each key material associated with a KMS key.

If this operation fails, use the exception to help determine the problem. If the error is related to the key material, the import token, or wrapping key, use GetParametersForImport to get a new public key and import token for the KMS key and repeat the import procedure. For help, see Create a KMS key with imported key material in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:ImportKeyMaterial (key policy)

Related operations:

Eventual consistency: The KMS API follows an eventual consistency model. For more information, see KMS eventual consistency.

May throw DependencyTimeoutException. May throw ExpiredImportTokenException. May throw IncorrectKeyMaterialException. May throw InvalidArnException. May throw InvalidCiphertextException. May throw InvalidImportTokenException. May throw KMSInternalException. May throw KMSInvalidStateException. May throw NotFoundException. May throw UnsupportedOperationException.

Parameter encryptedKeyMaterial : The encrypted key material to import. The key material must be encrypted under the public wrapping key that GetParametersForImport returned, using the wrapping algorithm that you specified in the same GetParametersForImport request.

Parameter importToken : The import token that you received in the response to a previous GetParametersForImport request. It must be from the same response that contained the public key that you used to encrypt the key material.

Parameter keyId : The identifier of the KMS key that will be associated with the imported key material. This must be the same KMS key specified in the KeyID parameter of the corresponding GetParametersForImport request. The Origin of the KMS key must be EXTERNAL and its KeyState must be PendingImport.

The KMS key can be a symmetric encryption KMS key, HMAC KMS key, asymmetric encryption KMS key, or asymmetric signing KMS key, including a multi-Region key of any supported type. You cannot perform this operation on a KMS key in a custom key store, or on a KMS key in a different Amazon Web Services account.

Specify the key ID or key ARN of the KMS key.

For example:

  • Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
  • Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey.

Parameter expirationModel : Specifies whether the key material expires. The default is KEY_MATERIAL_EXPIRES. For help with this choice, see Setting an expiration time in the Key Management Service Developer Guide.

When the value of ExpirationModel is KEY_MATERIAL_EXPIRES, you must specify a value for the ValidTo parameter. When value is KEY_MATERIAL_DOES_NOT_EXPIRE, you must omit the ValidTo parameter.

You cannot change the ExpirationModel or ValidTo values for the current import after the request completes. To change either value, you must reimport the key material.

Parameter importType : Indicates whether the key material being imported is previously associated with this KMS key or not. This parameter is optional and only usable with symmetric encryption keys. If no key material has ever been imported into the KMS key, and this parameter is omitted, the parameter defaults to NEW_KEY_MATERIAL. After the first key material is imported, if this parameter is omitted then the parameter defaults to EXISTING_KEY_MATERIAL.

For multi-Region keys, you must first import new key material into the primary Region key. You should use the NEW_KEY_MATERIAL import type when importing key material into the primary Region key. Then, you can import the same key material into the replica Region key. The import type for the replica Region key should be EXISTING_KEY_MATERIAL.

Parameter keyMaterialDescription : Description for the key material being imported. This parameter is optional and only usable with symmetric encryption keys. If you do not specify a key material description, KMS retains the value you specified when you last imported the same key material into this KMS key.

Parameter keyMaterialId : Identifies the key material being imported. This parameter is optional and only usable with symmetric encryption keys. You cannot specify a key material ID with ImportType set to NEW_KEY_MATERIAL. Whenever you import key material into a symmetric encryption key, KMS assigns a unique identifier to the key material based on the KMS key ID and the imported key material. When you re-import key material with a specified key material ID, KMS:

  • Computes the identifier for the key material
  • Matches the computed identifier against the specified key material ID
  • Verifies that the key material ID is already associated with the KMS key
To get the list of key material IDs associated with a KMS key, use ListKeyRotations.

Parameter validTo : The date and time when the imported key material expires. This parameter is required when the value of the ExpirationModel parameter is KEY_MATERIAL_EXPIRES. Otherwise it is not valid.

The value of this parameter must be a future date and time. The maximum value is 365 days from the request date.

When the key material expires, KMS deletes the key material from the KMS key. Without its key material, the KMS key is unusable. To use the KMS key in cryptographic operations, you must reimport the same key material.

You cannot change the ExpirationModel or ValidTo values for the current import after the request completes. To change either value, you must delete (DeleteImportedKeyMaterial) and reimport the key material.

Implementation

Future<ImportKeyMaterialResponse> importKeyMaterial({
  required Uint8List encryptedKeyMaterial,
  required Uint8List importToken,
  required String keyId,
  ExpirationModelType? expirationModel,
  ImportType? importType,
  String? keyMaterialDescription,
  String? keyMaterialId,
  DateTime? validTo,
}) async {
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'TrentService.ImportKeyMaterial'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'EncryptedKeyMaterial': base64Encode(encryptedKeyMaterial),
      'ImportToken': base64Encode(importToken),
      'KeyId': keyId,
      if (expirationModel != null) 'ExpirationModel': expirationModel.value,
      if (importType != null) 'ImportType': importType.value,
      if (keyMaterialDescription != null)
        'KeyMaterialDescription': keyMaterialDescription,
      if (keyMaterialId != null) 'KeyMaterialId': keyMaterialId,
      if (validTo != null) 'ValidTo': unixTimestampToJson(validTo),
    },
  );

  return ImportKeyMaterialResponse.fromJson(jsonResponse.body);
}