A general purpose BGA security cap includes a substrate, an integrated circuit die, and an array of bond balls. The substrate includes an anti-tamper security mesh of conductors. The bond balls include outer bond balls and inner bond balls that are fixed to the underside of the substrate. The integrated circuit drives and monitors the anti-tamper security mesh and communicates data using a serial physical interface through a subset of the inner bond balls. In one example, a user has circuitry to be protected. The user purchases the BGA security cap and fits it over the circuitry to be protected such that the integrated circuit of the security cap communicates tamper detect condition information via the serial interface to the underlying protected circuitry and causes sensitive information to be erased or a program to be halted in the event of a tamper condition.