Abstract: Security can be provided for lottery tickets having data printed thereon in a bar code or other machine readable media by covering only a portion of the bar code with a scratch-off material. Removing the scratch-off material, or in some cases only a portion of the scratch-off material, can permit machine validation of the lottery tickets. For bar codes having a specified level of redundancy, it is desirable to cover at least enough of the bar code to prevent the machine reading of ticket validation data encoded in the bar code. Also, a lottery ticket can include a bar code printed on the ticket having both inventory and validation data along with a bar code printed on the front of the ticket including the validation data. All or part of the bar code printed on the front of the ticket can be covered by a scratch-off material.