Computing the signature

The signature is computed by following the same procedure as for creating the payment form.

The data submitted by the payment gateway is encoded in UTF-8.

Any alteration of received data will result in signature computation error.

To compute the signature:

  1. Take all the fields whose name starts with vads_.
  2. Sort these fields alphabetically.
  3. Concatenate the values of these fields separating them with the "+" character.
  4. Concatenate the result with the production key separating them with a "+".
  5. Compute and encode in Base64 format the signature using the HMAC-SHA-256 algorithm with the following parameters:
    • the SHA-256 hash function,
    • the test or production key (depending on the value of the vads_ctx_mode field) as a shared key,
    • the result of the previous step as the message to authenticate.