The electoral system in Venezuela mandates electronic voting. By law, each machine must print its results before sending the tally to a central server.
Multiple copies are printed. One goes to the CNE, another goes to the military, and several others are given to witnesses representing different political parties.
Each copy must be signed by all the witnesses, including the representative from the CNE.
The opposition candidate gathered as much as 80% of the total printouts and made them available for everyone to see and analyze.
Printouts can be validated because the result is digitally signed with a key that is known to the political parties and other organizations. The signature is at the end of each printout.