A rare type of ROM. Voltage levels are set by firing a laser at traces to set/clear bits.

sergei_p_skorobogatov_016_laser_rom.jpg
Original caption: “Laser ROM in Dallas DS1961S iButton chip. Information can be read optically and altered with a laser cutter.” Copyright 2005 Sergei P. Skorobogatov, used with permission

References

  1. “Semi-invasive attacks - A new approach to hardware security analysis.” Sergei P. Skorobogatov.
  2. http://www.maxim-ic.com/datasheet/index.mvp/id/3557