Thanks for the reply. Yes, I have already written to them, but they have not replied. In the link I have attached this is indicated
Is formed using the request body and the secret by this algorithm:
All keys of the object of the request body are sorted alphabetically;
All values of the object of the request body are merged into a string with adding a secret at the end, which you get when logging into the system;
The entire string is hashed by the sha256 method
hash('sha256', parama_A + param_D + pamam_B + param_C + 123 + secret)