Banks and retailers have teamed up for the 'Chip and PIN' programme, which pledges a more secure way to use credit, debit and charge cards.
Four won a competitive pitch to handle the account, which is understood to carry fees in excess of £200,000.
Four will target card-holders, retailers and technology vendors to promote the programme, by which card-holders will authorise purchases by keying in a four-digit PIN rather than signing a receipt.
The system will be tested in Northampton over a 15-week period this spring, with national roll-out expected to be completed by December next year.
Four will operate a press office for Chip and PIN, in addition to handling consumer awareness, education programmes and crisis and issues management work.
Four managing partner Nan Williams leads a six-strong account team, alongside partners Einir Williams and Ray Eglington, reporting to Chip and PIN comms director Steve Sinclair.