Computing the signature

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

All the received fields must be included.

To compute the signature:

  1. Take all the fields starting with vads_.
  2. Sort these fields alphabetically.
  3. Make sure that all the fields are encoded in UTF-8.
  4. Concatenate the result with the test or production certificate by separating them with a "+".
  5. Apply the SHA-1 algorithm to obtain the signature value.