Side-channel attack

What is a side-channel attack?

A side-channel attack (SCA) is a security exploit that attempts to extract secrets from a chip or a system. This can be achieved by measuring or analysing various physical parameters. Examples include supply current, execution time, and electromagnetic emission. These attacks pose a serious threat to modules that integrate cryptographic systems. Indeed, many side-channel analysis techniques have proven successful in breaking an algorithmically robust cryptographic operation and extracting the secret key.

How does a side channel attack work?

A side-channel attack does not target a program or its code directly. Rather, a side-channel attack attempts to gather information or influence the program execution of a system by measuring or exploiting indirect effects of the system or its hardware. Put simply, a side channel attack breaks cryptography by exploiting information inadvertently leaked by a system. One such example is van Eck phreaking attack, which is also known as a Transient Electromagnetic Pulse Emanation Standard (TEMPEST). This attack monitors the electromagnetic field (EMF) radiation emitted by a computer screen to view information before it is encrypted.

Any computational system affects its environment in some form. This effect it has on its environment includes a wide range of criteria, which can range from electromagnetic radiation to residual effect on RAM cells which as a consequence make a Cold boot attack possible, to hardware implementation faults that allow for access and or guessing of other values that normally should be inaccessible. In Side-channel attack scenarios, the attacker would gather such information about a system or network to guess its internal state and as a result access the information which is assumed by the victim to be secure.