It is known for a gaining machine to issue a ticket or voucher having a value or an associated value as credit. It is a problem that such information carriers may become lost or stolen and subsequently redeemed by others. In the disclosed method, a player first registers and provides a first code to a gaming establishment and a value of credit available with which to play. A ticket is issued with a generated second code. On inserting the ticket in a gaming machine, prior to gaming being permitted, the gaming machine detects the second code and requires the player to enter the first code. The gaming machine validates the codes at the machine against corresponding codes stored elsewhere and permits gaming only when at least one of the codes matches. Thus, a ticket in accordance with the present invention will not be suitable for use other than by the player to whom the information carrier belongs since a third party will not have access to either the player provided code or the generated ticket code.