When ballots are sorted the counting officer must distinguish valid ballots from counterfeits. Each ballot in the ballot box needs to be verified. In some jurisdictions, security paper is often used for ballots.

This paper contains a watermark or other form of unique identification (special colour, lines, symbols, or logos) making the ballot virtually impossible to counterfeit. The texture, thickness, colours, size, and format of the ballot are also indicators that will differentiate a valid ballot from a counterfeit.

The counting officer should know where to look on the ballot to be sure of its authenticity. If he/she doesn't recognise the ballot or the ballot was not issued at the voting station, it should not be included in the count and should be put aside.

To speed up the process of authenticating the ballots, certain jurisdictions require that the voting station officer append their initials in a provided space at the back of the ballot before handing it to the voter.

If the initials at the back of the ballot are not from the voting station officer or are missing, then it should be set aside and not counted as a valid ballot. These initials should appear on the ballot account form, transportation form, the seals, or voting record book. If no initials are on the back of the ballot, the ballot should not be counted as valid.

This measure of appending a voting station officer’s initial at the back of the ballot can help to identify valid ballots from counterfeit ones, but the official's initial should always be identical to protect the voter's secrecy of the vote. The voting station officer should always use the same colour of pen or pencil to append his/her initials.

In all cases, all ballots are kept, even if they are not valid. No ballots should be destroyed (at this stage of the process, see Challenging Results for more details on how long ballots should be kept) as an audit trail of all ballots considered must be assembled so that the count can be fully reconstructed.