CyberGlossary

Vulnerabilities

Hardware Trojan

Also known as: Silicon Trojan, Chip-level Trojan

Definition

A malicious modification of an integrated circuit, inserted during design or fabrication, that triggers covert behaviour such as data leakage or denial of service.

A hardware Trojan is a deliberate, hidden alteration of a chip's logic, layout, or firmware introduced somewhere in the supply chain — by a rogue designer, a third-party IP block, an untrusted foundry, or during packaging. Triggers are typically rare conditions (specific inputs, time, temperature) to evade testing; payloads include leaking cryptographic keys, downgrading entropy, opening backdoors, or disabling the chip on demand. Detection is hard because post-silicon inspection is destructive and functional testing rarely exercises the trigger. Defences combine trusted-foundry programs, formal equivalence checking of RTL against masks, side-channel-based screening, split manufacturing, and provenance attestation.

Examples

  • A rogue IP core that leaks an AES key over an unused JTAG pin when a magic input is observed.
  • A counterfeit microcontroller whose RNG quietly produces predictable values.

Related terms