The Yidun captcha service uses the signature method to authenticate the interface. Each request of all interfaces needs to include signature information (signature parameter) to verify the user's identity and prevent the information from being maliciously tampered with.
Request a Security Credential
Before using the API for the first time, you need to apply for a security credential. The security credential includes SecretId and SecretKey . SecretId is used to identify the API, and SecretKey is the key used to encrypt the signature string and verify the signature string on the server side. SecretKey must be kept strictly to avoid leakage.