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unwrap-keys.md

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188 lines (144 loc) · 8.62 KB
copyright lastupdated keywords subcollection
years
2017, 2024
2024-10-09
unwrap key, decrypt key, decrypt data encryption key
key-protect

{:shortdesc: .shortdesc} {:screen: .screen} {:pre: .pre} {:table: .aria-labeledby="caption"} {:external: target="_blank" .external} {:codeblock: .codeblock} {:tip: .tip} {:note: .note} {:important: .important} {:term: .term} {:ui: .ph data-hd-interface='ui'} {:api: .ph data-hd-interface='api'}

Unwrapping keys

{: #unwrap-keys}

{{site.data.keyword.keymanagementservicelong}} combines the strength of multiple algorithms to protect the privacy and the integrity of your encrypted data. You can unwrap a data encryption key{: term} (DEK), to access its contents by using the {{site.data.keyword.keymanagementservicefull}} API and Console. Unwrapping a DEK decrypts and checks the integrity of its contents, returning the original key material to your {{site.data.keyword.cloud_notm}} data service. {: shortdesc}

To learn how key wrapping helps you control the security of at rest data in the cloud, see Protecting data with envelope encryption. {: tip}

Unwrapping a key using the console

{: #unwrapping-keys-ui} {: ui}

If you already have an instance of {{site.data.keyword.keymanagementserviceshort}} and you wish to encrypt your DEK by using a graphical interface, you can use the {{site.data.keyword.cloud_notm}} console.

After you import or create your own keys, complete the following steps to wrap your data using the key:

  1. Log in to the {{site.data.keyword.cloud_notm}} console{: external}.

  2. From the Menu, choose the Resource List to view a list of your resources.

  3. From your {{site.data.keyword.cloud_notm}} resource list, select your provisioned instance of {{site.data.keyword.keymanagementserviceshort}}.

  4. Choose the Root key that you used to originally wrap your data from the list of your keys.

  5. Click the ⋯ icon to open a list of options for the DEK that you want to unwrap.

  6. Click the Envelope encryption option to open the side panel. Choose the "Unwrap key" tab if it is not already highlighted.

  7. Supply any required text for the above in the appropriate fields, including the ciphertext and any additional data you stored locally for the purpose of unwrapping the DEK.

  8. Click Unwrap Key button.

Unwrapping keys by using the API

{: #unwrap-key-api} {: api}

After you make a wrap call to the service, you can unwrap a specified data encryption key (DEK) to access its contents by making a POST call to the following endpoint.

https://<region>.kms.cloud.ibm.com/api/v2/keys/<keyID_or_alias>/actions/unwrap

{: codeblock}

Root keys that contain the same key material can unwrap the same data encryption key (WDEK). {: note}

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

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

    You can find the ID for a key in your {{site.data.keyword.keymanagementserviceshort}} instance by retrieving a list of your keys, or by accessing the {{site.data.keyword.keymanagementserviceshort}} dashboard.

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

  4. Run the following curl command to decrypt and authenticate the key material.

    $ curl -X POST \
    "https://<region>.kms.cloud.ibm.com/api/v2/keys/<keyID_or_alias>/actions/unwrap" \
    -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>",
            "aad": [
                "<additional_data>",
                "<additional_data>"
            ]
        }'

    {: codeblock}

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

Variable Description
region Required. The region abbreviation, such as us-south or eu-gb, that represents the geographic area where your {{site.data.keyword.keymanagementserviceshort}} instance resides.

For more information, see Regional service endpoints.
keyID_or_alias Required. The unique identifier or alias for the root key that you used for the initial wrap request.
IAM_token Required. Your {{site.data.keyword.cloud_notm}} 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 {{site.data.keyword.keymanagementserviceshort}} service instance.

For more information, see Retrieving an instance ID.
key_ring_ID Optional. The unique identifier of the key ring that the key is a part of. If unspecified, {{site.data.keyword.keymanagementserviceshort}} will search for the key in every key ring associated with the specified instance. It is recommended 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 Grouping keys.
correlation_ID Optional.The unique identifier that is used to track and correlate transactions.
additional_data Optional.The additional authentication data (AAD) that is used to further secure the key. Each string can hold up to 255 characters. If you supply AAD when you make a wrap call to the service, you must specify he same AAD during the unwrap call.
encrypted_data_key Required. The ciphertext value that was returned during a wrap operation.
{: caption="Describes the variables that are needed to unwrap keys in {{site.data.keyword.keymanagementserviceshort}}." caption-side="top"}

The original key material is returned in the response entity-body. The response body also contains the ID of the key version that was used to unwrap the supplied ciphertext.

The plaintext that is returned is base64 encoded. For more information on how to decode your key material, see Decoding your key material. The following JSON object shows an example returned value.

{
    "plaintext": "Rm91ciBzY29yZSBhbmQgc2V2ZW4geWVhcnMgYWdv",
    "keyVersion": {
        "id": "02fd6835-6001-4482-a892-13bd2085f75d"
    }
}

If {{site.data.keyword.keymanagementserviceshort}} detects that you rotated the root key that is used to unwrap and access your data, the service also returns a newly wrapped data encryption key (ciphertext) in the unwrap response body. The latest key version (rewrappedKeyVersion) that is associated with the new ciphertext is also returned. Store and use the new ciphertext value for future envelope encryption operations so that your data is protected by the latest root key.

Decoding your key material

{: #how-to-decode-key-material}

When you unwrap a data encryption key, the key material is returned in base64 encoding. You will need to decode the key before encrypting it.

Using OpenSSL to decode key material

{: #open-ssl-encoding-root-unwrap}

  1. Download and install OpenSSL{: external}.

  2. Decode your base64 encoded key material string by running the following command:

    openssl base64 -d -in <infile> -out <outfile>

    {: pre}

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

Variable Description
infile The name of the file where your base64 encoded key material string resides.
outfile The name of the file where your decoded key material will be be outputted once the command has ran.
{: caption="Describes the variables that are needed to decode your key material." caption-side="top"}

If you want to output the decoded material in the command line directly rather than a file, run the command openssl enc -base64 -d <<< '<key_material_string>', where key_material_string is the returned plaintext from your unwrap request. {: note}