About customer main keys

As part of our commitment to end-to-end security, Webex holds a main key on behalf of each organization. We call it a main key because it doesn't encrypt content directly, but it's used to encrypt your organization's other keys which encrypt the content. The base level of the key hierarchy is called the content key (CK) and the intermediate levels of the keys are called key encryption keys (KEK).

We recognize that some organizations prefer to manage their own security, so we are giving you the option to manage your own customer main key (CMK). This means that you take responsibility for creating and rotating (reencrypting) the main key that Webex uses to encrypt your content encryption keys.

Going forward, a key refers to the CMK unless otherwise specified.

How it works

  1. Webex keeps your CMK in a hardware security module (HSM) so that the Webex services do not have access to the CMK value.

  2. Control Hub shows your currently active or revoked CMK and any pending CMK that are stored in the HSM. When you need to rotate (reencrypt) the CMK, you generate your new CMK and encrypt it with the HSM's public key, so that only the HSM can decrypt and store it.

  3. You then upload and activate the new CMK in Control Hub. Webex immediately starts using the new CMK for encrypting your content keys. Webex keeps the old CMK, but only until it's sure that your content encryption keys are secured by the new CMK.

We don’t retroactively reencrypt all the existing content. Once you activate your CMK, all new content (Spaces and Meetings) are reencrypted and protected.
About AWS KMS keys

We recognize that some organizations prefer to manage their own key outside of Webex. That's why we’re giving you the option to manage your own CMK in the Amazon Web Services (AWS) Key Management Service (KMS). This implies that you’re responsible for managing your keys in the AWS KMS. You authorize Webex to encrypt and decrypt using your AWS KMS key through the AWS console. You provide Webex with your AWS KMS key ID instead of your CMK. This means that you take responsibility for creating and rotating (reencrypting) the AWS KMS key that Webex uses to encrypt your content encryption keys in the cloud.

How it works

  1. You create a key with AWS. The AWS KMS is used to manage your key and stores the key in a hardware security module (HSM).

  2. You provide Webex with access to use the AWS KMS key through the AWS console.

    This means instead of uploading your CMK into Control Hub, you provide Webex with access to the AWS KMS key. The AWS KMS key doesn’t leave your AWS KMS and Webex services don’t have access to the AWS KMS key material.

    Control Hub shows your currently active or revoked AWS KMS key and any pending AWS KMS key that is stored in the AWS KMS. When you need to rotate the AWS KMS key, you generate your new AWS KMS key with the AWS KMS console.

  3. You then add and activate the new AWS KMS key in Control Hub, providing it with the Amazon Resource Name (ARN) of the new AWS KMS key. Webex immediately starts using the new AWS KMS key for encrypting your content keys. Webex no longer requires the old AWS KMS key. The old AWS KMS key will disappear from Control Hub after your content encryption keys are rotated and secured by the new AWS KMS key. Webex doesn’t delete the AWS KMS key from the AWS KMS. Your customer administrator can remove the key from the AWS KMS.

Key states and lifecycle

Key lifecycle

Key state definitions

Pending

A key in this state is stored in the HSM but it's not yet used for encryption. Webex doesn't use this CMK for encryption.

Only one key can be in this state.
Active

Webex is currently using this CMK to encrypt other keys for your organization.

Only one key can be in this state.
Rotation

Webex is temporarily using this CMK. Webex needs it to decrypt your data and keys that were previously encrypted by this key. This key is retired when rotation (reencrypting) is complete.

Multiple keys can be in this state if a new key is activated before rotation is complete.
Retired

Webex isn't using this CMK. This key is no longer used for encryption. A key time-to-live is set, after which this key is removed from the HSM.

Revoked

Webex isn't using this CMK. Even if there are data and keys that were encrypted with this key, Webex can't use it to decrypt the data and keys.

  • You only need to revoke an active key if you suspect it's compromised. This is a serious decision because it prevents many operations from behaving properly. For example, you won't be able to create new spaces, and you won't be able to decrypt any content in Webex Client.
  • Only one key can be in this state. You must reactivate this key to rotate (reencrypt) a new key.
  • This CMK can be deleted but you don’t have to delete it. You may want to keep it for decryption / reencrypting after you resolve the suspected security breach.
Deleted

Webex isn't using this CMK. The behavior in this state is the same as the Revoked state except that a key time-to-live is set, after which this key is removed from the HSM.

  • If a deleted CMK progresses to the Removed state, you must recover the original key to restore functionality to the organization.
  • We recommend that you keep a backup copy of your original key, otherwise your organization will no longer be functional.
Removed

This is a logical state. Webex doesn't have this CMK stored in the HSM. It's not displayed in Control Hub.

Requirements

Ownership

By taking ownership of your CMK, you must:

  • Take responsibility for secure creation and back up of your keys
  • Understand the implications of losing your keys
  • Reencrypt your active CMK at least once per year as a best practice

Key creation

You must create your own CMK using these parameters. Your key must be:

  • 256 bits (32 bytes) long
  • Encrypted with the RSA-OAEP scheme
  • Encrypted with the Webex cloud HSM public key

Your key generation software must be capable of:

  • SHA-256 hash function
  • MGF1 mask generation function
  • PKCS#1 OAEP padding

Refer to Example: Create and encrypt keys with OpenSSL in the Resources tab in this article.

Authorization

You must have access to your Webex organization in Control Hub. You must be a full administrator to manage your CMK.

Create and activate your customer main key
1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

To enable BYOK, toggle Bring Your Own Key (BYOK) on. If you disable BYOK, the Webex common default key becomes the main key for your organization.

3

Select Upload a custom key and click Next.

4

Click Download public key.

Save the Webex HSM public key in a .pem file on your local system.

5

Create a cryptographically secure 256-bit (32 byte) random key using your key management software.

6

Use the Webex HSM public key to encrypt your new key.

The required encryption parameters are:

  • RSA-OAEP scheme
  • SHA-256 hash function
  • MGF1 mask generation function
  • PKCS#1 OAEP padding
Refer to Example: Create and encrypt keys with OpenSSL in the Resources tab in this article.
7

Drag the encrypted key from your file system and drop it in the upload area of the Control Hub interface, or click Choose a file.

8

Click Next.

Webex uploads your key to the HSM, where it gets decrypted and validated. Then Control Hub shows you the ID of your new CMK, and the ID of the currently active CMK, if any.

If this is your first CMK, the currently active key is the Webex common default key (the one we currently use for encrypting your organization's keys).

9

Choose how you want to activate your key:

  • Activate new key: The new CMK immediately goes into the Active state. The previously active CMK goes into Rotation (Reencrypting state), until all your content is protected by the new CMK, after which Webex deletes the previously active CMK.
  • Activate later: The new CMK moves into the Pending state. Webex keeps this CMK in the HSM, but doesn’t use it yet. Webex continues using the currently active CMK for encrypting your organization's keys.

What to do next

We don’t retroactively reencrypt all the existing content. Once you activate your CMK, all new content (Spaces and Meetings) will be reencrypted and protected.
Rotate your key
1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

3

Go to the active CMK.

4

Click More menu and select Rotate.

5

Create and encrypt a new key (if you haven't yet done that).

The process is described in Create and activate your customer main key in this article.
6

Drag the new key from your file system and drop it in Control Hub.

7

Click Activate new key.

The new key that you uploaded goes into the Active state.

The old CMK stays in Rotation (Reencrypting state) until Webex finishes encrypting all its content with the new Active CMK. After reencrypting, the key moves into the Retired state. Webex then deletes the old CMK.

Revoke your key
1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

3

Go to the active key.

4

Click More menu and select Revoke.

5

Confirm the key revocation.

It can up to 10 minutes to fully revoke your key.
Reactivate your revoked key
1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

3

Go to the currently revoked key.

4

Click More menu and select Activate.

5

Confirm the key activation.

The previously revoked key goes into the Active state.
Delete your revoked key
1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

3

Go to the revoked key.

4

Click More menu and select Delete.

5

Confirm the key deletion.

Once deleted, you have the option to restore the key within 30 days.
Restore your revoked key
1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

3

Go to the deleted key.

4

Click More menu and select Undelete.

5

Confirm the key restoration.

Once restored, Control Hub shows you the key in the Revoked state before it was deleted. For example, if you delete a revoked key and then restore the key, Control Hub shows the restored key in the Revoked state.

Requirements

Ownership

By taking ownership of your AWS KMS key, you must:

  • Take responsibility for the secure creation and back up of your AWS KMS keys.
  • Understand the implications of losing your AWS KMS keys.
  • Reencrypt your active AMS KMS key at least once per year as a best practice.

Authorization

  • You must be authorized to create and manage your keys in the AWS KMS for your Webex organization.
  • You must have access to your Webex organization in Control Hub. You must be a full administrator to manage your AWS KMS key.
Create an AWS KMS key
1

Sign in to AWS and go to the AWS KMS console.

2

Select Customer managed keys and then click Create key.

3

Create the key with the following attributes:

  • Key type—Select Symmetric.
  • Key usage—Select Encrypt and decrypt.
  • Labels—Enter the Alias, Description, and Tags.
  • Key administrators—Select your organization’s key administrator users and roles.
  • Key deletion—Check Allow key administrators to delete this key.
  • Key users—Select your organization’s key users and roles.
4

Click Next.

5

Review your settings and click Finish.

Your AWS KMS key is created.
6

Go to Customer managed keys and click the Alias or Key ID to view the ARN.

What to do next

We recommend that you keep a temporary copy of the ARN. This ARN is used to add and activate your AWS KMS key in Control Hub.

Authorize Cisco KMS with access to the AWS KMS key
1

Sign in to AWS and go to the AWS CloudShell console.

2

Run create-grant to authorize Webex as follows:

aws kms create-grant \
              --name {UNIQUE_NAME_FOR_GRANT} \
              --key-id {UUID_Of_AWS_KMS Key} \
              --operations Encrypt Decrypt DescribeKey \
              --grantee-principal {KMS_CISCO_USER_ARN} \
              --retiring-principal {KMS_CISCO_USER_ARN}
For example: 
aws kms create-grant \ 
              --name Cisco-KMS-xxxxxxxx-encrypt-decrypt \ 
              --key-id xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx \ 
              --operations Encrypt Decrypt DescribeKey \ 
              --grantee-principal arn:aws:iam::xxxxxxxxxxxx:user/kms-cisco-user \ 
              --retiring-principal arn:aws:iam::xxxxxxxxxxxx:user/kms- cisco-user
The KMS_CISCO_USER_ARN is specific to your organization. The ARN is shown in the Add your AWS key window when activating your new AWK KMS key in Control Hub.
Add and activate your AWS KMS key

Before you begin

You must create an AWS KMS key before activating it in Control Hub. Refer to Create an AWS KMS key in this article.

You must provide Webex with access to the AWS KMS key. Refer to Authorize Cisco KMS with access to the AWS KMS key in this article.

1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management, and toggle Bring Your Own Key (BYOK) on.

If you disable BYOK, the Webex common default key becomes the main key for your organization.

3

Select Add AWS KMS key and click Next.

4

Get the ARN from the AWS console.

5

Enter the ARN in Control Hub and click Add.

Your key ARN gets uploaded to the Cisco KMS, where access to the key is validated. Then Control Hub shows you the Cisco KMS key ID of your new AWS KMS key, and the currently active Cisco KMS key ID, if any.

If this is your first AWS KMS key, the currently active key is the Webex common default key (the one we currently use for encrypting your organization's keys).

6

Choose how you want to activate your key:

  • Activate: The new AWS KMS key immediately goes into the Active state.
  • Activate later: The new AWS KMS key moves into the Pending state. Webex keeps this AWS KMS key ARN in the Cisco KMS, but doesn’t use it yet. Webex continues using the currently active AWS KMS key for encrypting your organization's keys.
Rotate your AWS KMS key
1

Sign in to Control Hub, and go to Organization Settings > Key Management.

2

Go to the active AWS KMS key.

3

Click More menu and select Rotate.

4

Enter your new AWS KMS key and new ARN and click Add.

The process is described in Add and activate your AMS KMS key in this article.
5

Click Activate.

The new AWS KMS key that you uploaded goes into the Active state.

The old AWS KMS key stays in the Rotating state until Webex finishes encrypting all its content with the new Active AWS KMS key. After reencrypting, the old AWS KMS key automatically disappears from Control Hub.

Rotate to add another AWS KMS key (optional)
1

Sign in to Control Hub, and go to Organization Settings > Key Management.

2

Click Add another key.

3

Enter your new AWS KMS key and click Add.

Control Hub shows you the Cisco KMS key ID of your new AWS KMS key, and the ID of the currently active Cisco KMS key ID.

The process is described in Add and activate your AMS KMS key in this article.

4

Click Activate.

The new AWS KMS key that you uploaded goes into the Active state.

The old AWS KMS key stays in the Rotating state until Webex finishes encrypting all its content with the new Active AWS KMS key. After reencrypting, the old AWS KMS key automatically disappears from Control Hub.

Revoke your AWS KMS key
1

Sign in to Control Hub, and go to Organization Settings > Key Management.

2

Go to the currently active AWS KMS key.

3

Click More menu and select Locally revoke.

4

Confirm the key revocation.

It can up to 10 minutes to fully revoke your key. The AWS KMS key goes into the Locally revoked state.

If your customer administrator revokes the key from the AWS KMS console, then the AWS KMS key is shown in the Revoked by Amazon state in Control Hub.

Delete your AWS KMS key
1

Sign in to Control Hub, and go to Organization Settings > Key Management.

2

Go to the revoked AWS KMS key.

3

Click More menu and select Delete.

4

Confirm the key deletion.

Once deleted, you can recover the key within 30 days.

We recommend that you delete the AWS KMS key from Control Hub first before deleting your CMK from the AWS console. If you delete your CMK from the AWS console before deleting the AWS KMS key in Control Hub, you may run into problems.

Ensure that the AWS KMS key is no longer visible in Control Hub before deleting your CMK from the AWS console.

Restore your AWS KMS key
1

Sign in to Control Hub, and go to Organization Settings > Key Management.

2

Go to the deleted AWS KMS key.

3

Click More menu and select Undelete.

4

Confirm the key restoration.

Once restored, Control Hub shows you the key in the Revoked state.

Troubleshoot your AWS KMS key

If you run into problems with your AWS KMS key, use the following information to troubleshoot it.

  • AWS KMS key ARN. For example, arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab.

  • Grants on the AWS KMS key.

  • AWS KMS key state. For example, the AWS KMS key is disabled.

Example: Create and encrypt keys with OpenSSL

This example uses version 3.0 of the OpenSSL command line tools. See OpenSSL for more about these tools.

1

Sign in to Control Hub.

2

Go to Organization Settings > Key Management.

3

Click Download public key.

You get the Webex HSM public key in a .pem file on your local system.

4

Create a 256-bit (32 byte) key: openssl rand -out main_key.bin 32.

The example uses the filename main_key.bin for your unencrypted new key.

Alternatively, you can generate a 32-byte random value using Hex dump, Python, or online generators. You can also create and manage your AWS KMS key.

5

Use the Webex HSM public key to encrypt your new key:

openssl pkeyutl -encrypt -pubin -inkey path/to/public.pem -in main_key.bin -out main_key_encrypted.bin -pkeyopt rsa_padding_mode:oaep -pkeyopt rsa_oaep_md:sha256

The example uses the filename main_key_encrypted.bin for the encrypted output key, and the filename path/to/public.pem for the Webex public key.

The encrypted key is ready for you to upload to Control Hub.

Related reading