createKey method

Future<CreateKeyResponse> createKey({ bool? bypassPolicyLockoutSafetyCheck, String? customKeyStoreId, CustomerMasterKeySpec? customerMasterKeySpec, String? description, KeyUsageType? keyUsage, OriginType? origin, String? policy, List<Tag>? tags, })

Creates a unique customer managed customer master key (CMK) in your AWS account and Region.

You can use the CreateKey operation to create symmetric or asymmetric CMKs.

• Symmetric CMKs contain a 256-bit symmetric key that never leaves AWS KMS unencrypted. To use the CMK, you must call AWS KMS. You can use a symmetric CMK to encrypt and decrypt small amounts of data, but they are typically used to generate data keys and data keys pairs. For details, see GenerateDataKey and GenerateDataKeyPair.
• Asymmetric CMKs can contain an RSA key pair or an Elliptic Curve (ECC) key pair. The private key in an asymmetric CMK never leaves AWS KMS unencrypted. However, you can use the GetPublicKey operation to download the public key so it can be used outside of AWS KMS. CMKs with RSA key pairs can be used to encrypt or decrypt data or sign and verify messages (but not both). CMKs with ECC key pairs can be used only to sign and verify messages.

For information about symmetric and asymmetric CMKs, see Using Symmetric and Asymmetric CMKs in the AWS Key Management Service Developer Guide.

To create different types of CMKs, use the following guidance:

Asymmetric CMKs

To create an asymmetric CMK, use the CustomerMasterKeySpec parameter to specify the type of key material in the CMK. Then, use the KeyUsage parameter to determine whether the CMK will be used to encrypt and decrypt or sign and verify. You can't change these properties after the CMK is created.

Symmetric CMKs

When creating a symmetric CMK, you don't need to specify the CustomerMasterKeySpec or KeyUsage parameters. The default value for CustomerMasterKeySpec, SYMMETRIC_DEFAULT, and the default value for KeyUsage, ENCRYPT_DECRYPT, are the only valid values for symmetric CMKs.

Imported Key Material

To import your own key material, begin by creating a symmetric CMK with no key material. To do this, use the Origin parameter of CreateKey with a value of EXTERNAL. Next, use GetParametersForImport operation to get a public key and import token, and use the public key to encrypt your key material. Then, use ImportKeyMaterial with your import token to import the key material. For step-by-step instructions, see Importing Key Material in the AWS Key Management Service Developer Guide . You cannot import the key material into an asymmetric CMK.

Custom Key Stores

To create a symmetric CMK in a custom key store, use the CustomKeyStoreId parameter to specify the custom key store. You must also use the Origin parameter with a value of AWS_CLOUDHSM. The AWS CloudHSM cluster that is associated with the custom key store must have at least two active HSMs in different Availability Zones in the AWS Region.

You cannot create an asymmetric CMK in a custom key store. For information about custom key stores in AWS KMS see Using Custom Key Stores in the AWS Key Management Service Developer Guide .

Cross-account use: No. You cannot use this operation to create a CMK in a different AWS account.

Required permissions: kms:CreateKey (IAM policy). To use the Tags parameter, kms:TagResource (IAM policy). For examples and information about related permissions, see Allow a user to create CMKs in the AWS Key Management Service Developer Guide.

Related operations:

• DescribeKey
• ListKeys
• ScheduleKeyDeletion

May throw MalformedPolicyDocumentException. May throw DependencyTimeoutException. May throw InvalidArnException. May throw UnsupportedOperationException. May throw KMSInternalException. May throw LimitExceededException. May throw TagException. May throw CustomKeyStoreNotFoundException. May throw CustomKeyStoreInvalidStateException. May throw CloudHsmClusterInvalidConfigurationException.

Parameter bypassPolicyLockoutSafetyCheck : A flag to indicate whether to bypass the key policy lockout safety check.

For more information, refer to the scenario in the Default Key Policy section in the AWS Key Management Service Developer Guide . Use this parameter only when you include a policy in the request and you intend to prevent the principal that is making the request from making a subsequent PutKeyPolicy request on the CMK.

The default value is false.

Parameter customKeyStoreId : Creates the CMK in the specified custom key store and the key material in its associated AWS CloudHSM cluster. To create a CMK in a custom key store, you must also specify the Origin parameter with a value of AWS_CLOUDHSM. The AWS CloudHSM cluster that is associated with the custom key store must have at least two active HSMs, each in a different Availability Zone in the Region.

This parameter is valid only for symmetric CMKs. You cannot create an asymmetric CMK in a custom key store.

To find the ID of a custom key store, use the DescribeCustomKeyStores operation.

The response includes the custom key store ID and the ID of the AWS CloudHSM cluster.

This operation is part of the Custom Key Store feature feature in AWS KMS, which combines the convenience and extensive integration of AWS KMS with the isolation and control of a single-tenant key store.

Parameter customerMasterKeySpec : Specifies the type of CMK to create. The default value, SYMMETRIC_DEFAULT, creates a CMK with a 256-bit symmetric key for encryption and decryption. For help choosing a key spec for your CMK, see How to Choose Your CMK Configuration in the AWS Key Management Service Developer Guide.

The CustomerMasterKeySpec determines whether the CMK contains a symmetric key or an asymmetric key pair. It also determines the encryption algorithms or signing algorithms that the CMK supports. You can't change the CustomerMasterKeySpec after the CMK is created. To further restrict the algorithms that can be used with the CMK, use a condition key in its key policy or IAM policy. For more information, see kms:EncryptionAlgorithm or kms:Signing Algorithm in the AWS Key Management Service Developer Guide. AWS KMS supports the following key specs for CMKs:

• Symmetric key (default)
  • SYMMETRIC_DEFAULT (AES-256-GCM)
• Asymmetric RSA key pairs
  • RSA_2048
  • RSA_3072
  • RSA_4096
• Asymmetric NIST-recommended elliptic curve key pairs
  • ECC_NIST_P256 (secp256r1)
  • ECC_NIST_P384 (secp384r1)
  • ECC_NIST_P521 (secp521r1)
• Other asymmetric elliptic curve key pairs
  • ECC_SECG_P256K1 (secp256k1), commonly used for cryptocurrencies.

Parameter description : A description of the CMK.

Use a description that helps you decide whether the CMK is appropriate for a task.

Parameter keyUsage : Determines the cryptographic operations for which you can use the CMK. The default value is ENCRYPT_DECRYPT. This parameter is required only for asymmetric CMKs. You can't change the KeyUsage value after the CMK is created.

Select only one valid value.

• For symmetric CMKs, omit the parameter or specify ENCRYPT_DECRYPT.
• For asymmetric CMKs with RSA key material, specify ENCRYPT_DECRYPT or SIGN_VERIFY.
• For asymmetric CMKs with ECC key material, specify SIGN_VERIFY.

Parameter origin : The source of the key material for the CMK. You cannot change the origin after you create the CMK. The default is AWS_KMS, which means AWS KMS creates the key material.

When the parameter value is EXTERNAL, AWS KMS creates a CMK without key material so that you can import key material from your existing key management infrastructure. For more information about importing key material into AWS KMS, see Importing Key Material in the AWS Key Management Service Developer Guide. This value is valid only for symmetric CMKs.

When the parameter value is AWS_CLOUDHSM, AWS KMS creates the CMK in an AWS KMS custom key store and creates its key material in the associated AWS CloudHSM cluster. You must also use the CustomKeyStoreId parameter to identify the custom key store. This value is valid only for symmetric CMKs.

Parameter policy : The key policy to attach to the CMK.

If you provide a key policy, it must meet the following criteria:

• If you don't set BypassPolicyLockoutSafetyCheck to true, the key policy must allow the principal that is making the CreateKey request to make a subsequent PutKeyPolicy request on the CMK. This reduces the risk that the CMK becomes unmanageable. For more information, refer to the scenario in the Default Key Policy section of the AWS Key Management Service Developer Guide .
• Each statement in the key policy must contain one or more principals. The principals in the key policy must exist and be visible to AWS KMS. When you create a new AWS principal (for example, an IAM user or role), you might need to enforce a delay before including the new principal in a key policy because the new principal might not be immediately visible to AWS KMS. For more information, see Changes that I make are not always immediately visible in the AWS Identity and Access Management User Guide.

If you do not provide a key policy, AWS KMS attaches a default key policy to the CMK. For more information, see Default Key Policy in the AWS Key Management Service Developer Guide.

The key policy size quota is 32 kilobytes (32768 bytes).

For help writing and formatting a JSON policy document, see the IAM JSON Policy Reference in the IAM User Guide .

Parameter tags : One or more tags. Each tag consists of a tag key and a tag value. Both the tag key and the tag value are required, but the tag value can be an empty (null) string.

When you add tags to an AWS resource, AWS generates a cost allocation report with usage and costs aggregated by tags. For information about adding, changing, deleting and listing tags for CMKs, see Tagging Keys.

Use this parameter to tag the CMK when it is created. To add tags to an existing CMK, use the TagResource operation.

To use this parameter, you must have kms:TagResource permission in an IAM policy.

Implementation

Future<CreateKeyResponse> createKey({
  bool? bypassPolicyLockoutSafetyCheck,
  String? customKeyStoreId,
  CustomerMasterKeySpec? customerMasterKeySpec,
  String? description,
  KeyUsageType? keyUsage,
  OriginType? origin,
  String? policy,
  List<Tag>? tags,
}) async {
  _s.validateStringLength(
    'customKeyStoreId',
    customKeyStoreId,
    1,
    64,
  );
  _s.validateStringLength(
    'description',
    description,
    0,
    8192,
  );
  _s.validateStringLength(
    'policy',
    policy,
    1,
    131072,
  );
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'TrentService.CreateKey'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      if (bypassPolicyLockoutSafetyCheck != null)
        'BypassPolicyLockoutSafetyCheck': bypassPolicyLockoutSafetyCheck,
      if (customKeyStoreId != null) 'CustomKeyStoreId': customKeyStoreId,
      if (customerMasterKeySpec != null)
        'CustomerMasterKeySpec': customerMasterKeySpec.toValue(),
      if (description != null) 'Description': description,
      if (keyUsage != null) 'KeyUsage': keyUsage.toValue(),
      if (origin != null) 'Origin': origin.toValue(),
      if (policy != null) 'Policy': policy,
      if (tags != null) 'Tags': tags,
    },
  );

  return CreateKeyResponse.fromJson(jsonResponse.body);
}