POST /#X-Amz-Target=TrentService.GenerateMac
Generates a hash-based message authentication code (HMAC) for a message using an HMAC KMS key and a MAC algorithm that the key supports. HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry standards defined in RFC 2104.
You can use value that GenerateMac returns in the VerifyMac operation to demonstrate that the original message has not changed. Also, because a secret key is used to create the hash, you can verify that the party that generated the hash has the required secret key. You can also use the raw result to implement HMAC-based algorithms such as key derivation functions. This operation is part of KMS support for HMAC KMS keys. For details, see HMAC keys in KMS in the Key Management Service Developer Guide .
Best practices recommend that you limit the time during which any signing mechanism, including an HMAC, is effective. This deters an attack where the actor uses a signed message to establish validity repeatedly or long after the message is superseded. HMAC tags do not include a timestamp, but you can include a timestamp in the token or message to help you detect when its time to refresh the HMAC.
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.
Required permissions: kms:GenerateMac (key policy)
Related operations: VerifyMac
Servers
- https://kms.{region}.amazonaws.com
- https://kms.{region}.amazonaws.com.cn
Request headers
| Name | Type | Required | Description |
|---|---|---|---|
X-Amz-Content-Sha256 |
String | No | |
X-Amz-Credential |
String | No | |
X-Amz-Target |
String | Yes |
Valid values:
|
Content-Type |
String | Yes |
The media type of the request body.
Default value: "application/json" |
X-Amz-Date |
String | No | |
X-Amz-Algorithm |
String | No | |
X-Amz-SignedHeaders |
String | No | |
X-Amz-Security-Token |
String | No | |
X-Amz-Signature |
String | No |
Request body fields
| Name | Type | Required | Description |
|---|---|---|---|
GrantTokens[] |
Array | No |
A list of grant tokens. Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency. For more information, see Grant token and Using a grant token in the Key Management Service Developer Guide. |
MacAlgorithm |
String | Yes |
The MAC algorithm used in the operation. The algorithm must be compatible with the HMAC KMS key that you specify. To find the MAC algorithms that your HMAC KMS key supports, use the DescribeKey operation and see the Valid values:
|
Message |
String | Yes |
The message to be hashed. Specify a message of up to 4,096 bytes. |
KeyId |
String | Yes |
The HMAC KMS key to use in the operation. The MAC algorithm computes the HMAC for the message and the key as described in RFC 2104. To identify an HMAC KMS key, use the DescribeKey operation and see the |
How to start integrating
- Add HTTP Task to your workflow definition.
- Search for the API you want to integrate with and click on the name.
- This loads the API reference documentation and prepares the Http request settings.
- Click Test request to test run your request to the API and see the API's response.