Rewrapping data encryption keys with root keys

Rewrapping keys by using the API

You can reencrypt a specified data encryption key (DEK) with a root key that you manage in Hyper Protect Crypto Services, without exposing the DEK in the plain text form.

Rewrapping keys works by combining unwrap and wrap calls to the service. For example, you can emulate a rewrap operation by first calling the unwrap API to access a DEK, and then calling the wrap API to reencrypt the DEK by using the newest root key material.

After you rotate a root key in the service, rewrap a data encryption key that is associated with the root key by making a POST call to the following endpoint.

https://<instance_ID>.api.<region>.hs-crypto.appdomain.cloud/api/v2/keys/<key_ID>/actions/rewrap

1. Retrieve your service and authentication credentials to work with keys in the service.

2. Copy the ID of the rotated root key that you used to perform the initial wrap request.

   You can retrieve the ID for a key by making a GET api/v2/keys request, or by viewing your keys in the UI.

3. Copy the ciphertext value that was returned during the latest wrap request.

4. Rewrap the key with the latest root key material by running the following cURL command.

   curl -X POST \
     'https://<instance_ID>.api.<region>.hs-crypto.appdomain.cloud/api/v2/keys/<key_ID>/actions/rewrap' \
     -H 'accept: application/vnd.ibm.kms.key_action+json' \
     -H 'authorization: Bearer <IAM_token>' \
     -H 'bluemix-instance: <instance_ID>' \
     -H 'content-type: application/vnd.ibm.kms.key_action+json' \
     -H "x-kms-key-ring: <key_ring_ID>" \
     -H 'correlation-id: <correlation_ID>' \
     -d '{
     "ciphertext": "<encrypted_data_key>"
   }'
   

   Replace the variables in the example request according to the following table.

   Table 1. Describes the variables needed to rewrap keys in Hyper Protect Crypto Services.

   Variable	Description
   region	Required. The region abbreviation, such as us-south or eu-de, that represents the geographic area where your Hyper Protect Crypto Services service instance resides. For more information, see Regional service endpoints.
   port	Required. The port number of the API endpoint.
   key_ID	Required. The unique identifier for the root key that you used for the initial wrap request.
   IAM_token	Required. Your IBM Cloud access token. Include the full contents of the IAM token, including the Bearer value, in the cURL request. For more information, see Retrieving an access token.
   instance_ID	Required. The unique identifier that is assigned to your Hyper Protect Crypto Services service instance. For more information, see Retrieving an instance ID.
   key_ring_ID	Optional. The unique identifier of the key ring that the key belongs to. If unspecified, Hyper Protect Crypto Services will search for the key in every key ring that is associated with the specified instance. Therefore, it is suggested to specify the key ring ID for a more optimized request. Note: The key ring ID of keys that are created without an x-kms-key-ring header is: default. For more information, see Managing key rings.
   correlation_ID	The unique identifier that is used to track and correlate transactions.
   encrypted_data_key	Required. The ciphertext value that was returned by the original wrap operation.

   The newly wrapped data encryption key, original key version (keyVersion) that is associated with the supplied ciphertext and latest key version (rewrappedKeyVersion) associated with the new ciphertext is returned in the response entity-body. The following JSON object shows an example returned value.

   {
     "ciphertext": "eyJjaX ... h0Ijoi ... c1ZCJ9",
     "keyVersion": {
       "id": "02fd6835-6001-4482-a892-13bd2085f75d"
     },
     "rewrappedKeyVersion": {
       "id": "12e8c9c2-a162-472d-b7d6-8b9a86b815a6"
     }
   }
   

   Store and use the new ciphertext value for future envelope encryption operations so that your data is protected by the latest root key.