To ensure the security of callback requests, it is strongly recommended to enable Webhook HMAC signature verification in production environments to prevent forged requests and replay attacks.
Algorithm Overview#
Kie AI uses the HMAC-SHA256 algorithm to generate signatures, ensuring the integrity and authenticity of webhook callbacks.Signature Generation Process:1.
Concatenate the data to sign: taskId + "." + timestampSecondstaskId: Task ID from the request body
timestampSeconds: Unix timestamp in seconds from the X-Webhook-Timestamp header
2.
Calculate HMAC-SHA256 signature:signature = HMAC-SHA256(dataToSign, webhookHmacKey)
3.
Base64 encode the signature:finalSignature = Base64.encode(signature)
Obtain Webhook HMAC Key#
The webhookHmacKey is used to verify that callback requests originate from Kie AI's official servers. Keep this key secure and never expose it or commit it to code repositories.
When you enable the webhookHmacKey feature in the settings page, all callback requests will include the following fields in the HTTP headers:X-Webhook-Timestamp#
Description: Unix timestamp (in seconds) when the callback request was sent.
X-Webhook-Signature#
Description: Signature generated using the HMAC-SHA256 algorithm with Base64 encoding.
Signature generation rule:#
base64(HMAC-SHA256(taskId + "." + timestamp, webhookHmacKey))
taskId is the task ID from the callback body
timestamp is the value of X-Webhook-Timestamp
webhookHmacKey is the key you generated in the console
Webhook Verification Process#
Follow these steps to verify the legitimacy of webhook requests:1
Read Header Fields
Extract the
X-Webhook-Timestamp and
X-Webhook-Signature fields from the HTTP headers.
2
Generate Signature
Using your locally stored
webhookHmacKey, generate the HMAC-SHA256 signature following these rules:
1.
Extract task_id from the request body
2.
Concatenate the string: taskId + "." + timestamp
3.
Generate signature using HMAC-SHA256 algorithm with webhookHmacKey
4.
Base64 encode the signature result
3
Compare Signatures
Compare the computed signature with
X-Webhook-Signature using a constant-time comparison algorithm to prevent timing attacks.
Complete Example Code#
Here are complete examples of implementing webhook signature verification in popular programming languages:Example Webhook Request#
Here's what a complete webhook request looks like: