Security Engineering, 3rd Edition

CHAPTER 18Tamper Resistance

It is relatively easy to build an encryption system that is secure if it is working as intended and is used correctly but it is still very hard to build a system that does not compromise its security in situations in which it is either misused or one or more of its sub-components fails (or is 'encouraged' to misbehave) … this is now the only area where the closed world is still a long way ahead of the open world and the many failures we see in commercial cryptographic systems provide some evidence for this.

– BRIAN GLADMAN

The amount of careful, critical security thinking that has gone into a given security device, system or program is inversely proportional to the amount of high-technology it uses.

– ROGER JOHNSTON

18.1 Introduction

Tamper-resistant devices are everywhere now. Examples we've discussed so far include:

• the EMV chips used in bank cards and the SIMs used in mobile phones for authentication;
• the contactless cards used as transport tickets and the smartcards used in pay-TV decoders for service control;
• chips used for accessory control in printer toner cartridges and game-console accessories;
• the TPM chips in phones, laptops and servers to provide a root of trust to support secure boot and hard-disk encryption;
• hardware security modules used to encrypt bank PINs, not just in bank server farms but in ATMs and some point-of-sale terminals;
• the NFC chips used in Android phones to store contactless payment credentials, and the enclave ...