Methods, systems, and computer program products for data entry device security are provided. Aspects include receiving an indication of a user presence at a data entry device, wherein the data entry device includes a surface with apertures, and wherein the apertures include a material with a reflection coefficient. A presence of a fraud device is determined by emitting, from beneath the surface, security light from a set of one or more emitters, wherein the security light has a security light luminous power. A reflection of the security light off the material is collected by a first set of one or more sensors, wherein the reflection has a reflection luminous power. A luminous power range is determined based on the security light luminous power and the reflection coefficient and based on the reflection luminous power being outside the luminous power range, security measures are engaged at the data entry device.