...
- invoke CA
- check validity of the DS
- If it is valid - do nothing (or save verification results to DS DB)
- If it is not valid:
- check attempts_counter
- if counter > configuration
- save failed verification result to digital_signature DB
- send warning email to administrator that includes verification_id and request_id.
- else
- put it back to the queue to be verified after X seconds (configuration)
- if counter > configuration
- check attempts_counter