Whether there was any contact as Martin Foster's set-piece curled into the box is debatable but Shaymen striker Neil Ross was not going to argue.
Ross blasted the penalty into the top left corner to register his fifth goal of the campaign after a short delay while Hankin was perhaps harshly booked and then lectured by the referee for his alleged foul.
It was enough for the Shaymen to stretch their impressive league form to only two defeats in the last 12 games and Halifax still have two matches in hand on most teams in the Conference play-off race.
But the home side did not have it all their own way on a poor pitch that cut up badly as the game went on.
Crawley controlled large chunks of play and Halifax midfield duo Steve Bushell and Foster had to be at their best to break play up before Ian Dunbavin's goal was threatened.
And when the Reds did get sight of the danger area they found the Town keeper in fine form. Dunbavin parried Daniel Marney's 64th minute long-range drive and, in stoppage time, Charlie MacDonald was denied a certain equaliser by the keeper's full-length dive.
Halifax had several chances to kill the game off before then but Lewis Killeen's diving header from a Denny Ingram centre on five minutes, Foster's long-range 22nd minute effort and a Ross header on 49 minutes from a Matt Doughty cross all missed the target.