The Dutch government has issued a warning this year about the security of access keys that are based on the widely used Mifare Classic RFID chip.

Government institutions plan to take "additional security measures to safeguard security, " Guusje ter Horst, minister of interior affairs, wrote in a letter to parliament on Wednesday.

Introduction

The encoding format used by the ISO/IEC-7811 standard is known as “F2F” or “Aiken Biphase” encoding. The F2F encoding format allows the serial data to be self-clocking. Bits are encoded serially on the magnetic stripe using a series of magnetic flux transitions. Each bit of data on a track has a fixed physical length on the magnetic stripe. Flux transitions are located at the edge of each bit, and also in the center of each “1” bit.