Creating keys - AWS Key Management Service

Creating keys

You can create AWS KMS keys in the AWS Management Console, or by using the CreateKey operation or an AWS CloudFormation template. During this process, you pick the type of the KMS key, its regionality (single-Region or multi-Region), and the origin of the key material (by default, AWS KMS creates the key material). You cannot change these properties after the KMS key is created. You also set the key policy for the KMS key, which you can change at any time.

This topic explains how to create the basic KMS key, a symmetric encryption KMS key for a single Region with key material from AWS KMS. You can use this KMS key to protect your resources in an AWS service. For detailed information about symmetric encryption KMS keys, see SYMMETRIC_DEFAULT key spec. For help creating other types of keys, see Special-purpose keys.

If you are creating a KMS key to encrypt data you store or manage in an AWS service, create a symmetric encryption KMS key. AWS services that are integrated with AWS KMS use only symmetric encryption KMS keys to encrypt your data. These services do not support encryption with asymmetric KMS keys. For help deciding which type of KMS key to create, see Choosing a KMS key type.

Note

Symmetric KMS keys are now called symmetric encryption KMS keys. AWS KMS supports two kinds of symmetric KMS keys, symmetric encryption KMS keys (the default type) and HMAC KMS keys, which are also symmetric keys.

When you create a KMS key in the AWS KMS console, you are required to give it an alias (friendly name). The CreateKey operation does not create an alias for the new KMS key. To create an alias for a new or existing KMS key, use the CreateAlias operation. For detailed information about aliases in AWS KMS, see Using aliases.

This topic explains how to create a symmetric encryption KMS key.

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Permissions for creating KMS keys

To create a KMS key in the console or by using the APIs, you must have the following permission in an IAM policy. Whenever possible, use condition keys to limit the permissions. For example, you can use the kms:KeySpec condition key in an IAM policy to allow principals to create only symmetric encryption keys.

For an example of an IAM policy for principals who create keys, see Allow a user to create KMS keys.

Note

Be cautious when giving principals permission to manage tags and aliases. Changing a tag or alias can allow or deny permission to the customer managed key. For details, see ABAC for AWS KMS.

The kms:PutKeyPolicy permission is not required to create the KMS key. The kms:CreateKey permission includes permission to set the initial key policy. But you must add this permission to the key policy while creating the KMS key to ensure that you can control access to the KMS key. The alternative is using the BypassLockoutSafetyCheck parameter, which is not recommended.

KMS keys belong to the AWS account in which they were created. The IAM user who creates a KMS key is not considered to be the key owner and they don't automatically have permission to use or manage the KMS key that they created. Like any other principal, the key creator needs to get permission through a key policy, IAM policy, or grant. However, principals who have the kms:CreateKey permission can set the initial key policy and give themselves permission to use or manage the key.

Creating symmetric encryption KMS keys

You can create KMS keys in the AWS Management Console or by using the AWS KMS API.

This topic explains how to create the basic KMS key, a symmetric encryption KMS key for a single Region with key material from AWS KMS. You can use this KMS key to protect your resources in an AWS service. For help creating other types of keys, see Special-purpose keys.

Creating symmetric encryption KMS keys (console)

You can use the AWS Management Console to create AWS KMS keys (KMS keys).

  1. Sign in to the AWS Management Console and open the AWS Key Management Service (AWS KMS) console at https://console.aws.amazon.com/kms.

  2. To change the AWS Region, use the Region selector in the upper-right corner of the page.

  3. In the navigation pane, choose Customer managed keys.

  4. Choose Create key.

  5. To create a symmetric encryption KMS key, for Key type choose Symmetric.

    For information about how to create an asymmetric KMS key in the AWS KMS console, see Creating asymmetric KMS keys (console).

  6. In Key usage, the Encrypt and decrypt option is selected for you.

    For information about how to create KMS keys that generate and verify MAC codes, see Creating HMAC KMS keys.

  7. Choose Next.

    For information about the Advanced options, see Special-purpose keys.

  8. Type an alias for the KMS key. The alias name cannot begin with aws/. The aws/ prefix is reserved by Amazon Web Services to represent AWS managed keys in your account.

    Note

    Adding, deleting, or updating an alias can allow or deny permission to the KMS key. For details, see ABAC for AWS KMS and Using aliases to control access to KMS keys.

    An alias is a display name that you can use to identify the KMS key. We recommend that you choose an alias that indicates the type of data you plan to protect or the application you plan to use with the KMS key.

    Aliases are required when you create a KMS key in the AWS Management Console. They are optional when you use the CreateKey operation.

  9. (Optional) Type a description for the KMS key.

    You can add a description now or update it any time unless the key state is Pending Deletion or Pending Replica Deletion. To add, change, or delete the description of an existing customer managed key, edit the description in the AWS Management Console or use the UpdateKeyDescription operation.

  10. (Optional) Type a tag key and an optional tag value. To add more than one tag to the KMS key, choose Add tag.

    Note

    Tagging or untagging a KMS key can allow or deny permission to the KMS key. For details, see ABAC for AWS KMS and Using tags to control access to KMS keys.

    When you add tags to your AWS resources, AWS generates a cost allocation report with usage and costs aggregated by tags. Tags can also be used to control access to a KMS key. For information about tagging KMS keys, see Tagging keys and ABAC for AWS KMS.

  11. Choose Next.

  12. Select the IAM users and roles that can administer the KMS key.

    Note

    This key policy gives the AWS account full control of this KMS key. It allows account administrators to use IAM policies to give other principals permission to manage the KMS key. For details, see Default key policy.

  13. (Optional) To prevent the selected IAM users and roles from deleting this KMS key, in the Key deletion section at the bottom of the page, clear the Allow key administrators to delete this key check box.

  14. Choose Next.

  15. Select the IAM users and roles that can use the key in cryptographic operations

    Note

    This key policy gives the AWS account full control of this KMS key. It allows account administrators to use IAM policies to give other principals permission to use the KMS key in cryptographic operations. For details, see Default key policy.

  16. (Optional) You can allow other AWS accounts to use this KMS key for cryptographic operations. To do so, in the Other AWS accounts section at the bottom of the page, choose Add another AWS account and enter the AWS account identification number of an external account. To add multiple external accounts, repeat this step.

    Note

    To allow principals in the external accounts to use the KMS key, Administrators of the external account must create IAM policies that provide these permissions. For more information, see Allowing users in other accounts to use a KMS key.

  17. Choose Next.

  18. Review the key settings that you chose. You can still go back and change all settings.

  19. Choose Finish to create the KMS key.

Creating symmetric encryption KMS keys (AWS KMS API)

You can use the CreateKey operation to create AWS KMS keys of all types. These examples use the AWS Command Line Interface (AWS CLI), but you can use any supported programming language.

The following operation creates the most commonly used KMS key, a symmetric encryption key in a single Region backed by key material generated by AWS KMS. This operation has no required parameters. However, you might also want to use the Policy parameter to specify a key policy. You can change the key policy (PutKeyPolicy) and add optional elements, such as a description and tags at any time. You can also create asymmetric keys, multi-Region keys, keys with imported key material, and keys in custom key stores.

The CreateKey operation doesn't let you specify an alias, but you can use the CreateAlias operation to create an alias for your new KMS key.

The following is an example of a call to the CreateKey operation with no parameters. This command uses all of the default values. It creates a symmetric encryption KMS key with key material generated by AWS KMS.

$ aws kms create-key { "KeyMetadata": { "Origin": "AWS_KMS", "KeyId": "1234abcd-12ab-34cd-56ef-1234567890ab", "Description": "", "KeyManager": "CUSTOMER", "Enabled": true, "KeySpec": "SYMMETRIC_DEFAULT", "CustomerMasterKeySpec": "SYMMETRIC_DEFAULT", "KeyUsage": "ENCRYPT_DECRYPT", "KeyState": "Enabled", "CreationDate": 1502910355.475, "Arn": "arn:aws:kms:us-west-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab", "AWSAccountId": "111122223333", "MultiRegion": false "EncryptionAlgorithms": [ "SYMMETRIC_DEFAULT" ], } }

If you do not specify a key policy for your new KMS key, the default key policy that CreateKey applies differs from the default key policy that the console applies when you use it to create a new KMS key.

For example, this call to the GetKeyPolicy operation returns the key policy that CreateKey applies. It gives the AWS account access to the KMS key and allows it to create AWS Identity and Access Management (IAM) policies for the KMS key. For detailed information about IAM policies and key policies for KMS keys, see Authentication and access control for AWS KMS

$ aws kms get-key-policy --key-id 1234abcd-12ab-34cd-56ef-1234567890ab --policy-name default --output text { "Version" : "2012-10-17", "Id" : "key-default-1", "Statement" : [ { "Sid" : "Enable IAM policies", "Effect" : "Allow", "Principal" : { "AWS" : "arn:aws:iam::111122223333:root" }, "Action" : "kms:*", "Resource" : "*" } ] }