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What is Logic locking?

A technique that adds gates whose function depends on a key value to a circuit, so that the chip does not work correctly until the correct key is written after manufacturing. It aims to prevent the foundry that manufactures the chip from stealing the design or selling extra chips it produced. Attacks in which an adversary who has obtained a working chip compares inputs and outputs and narrows down the key with a SAT solver have been demonstrated, and research on schemes that resist them continues.

Japanese name: ロジックロッキング

Logic locking appears in 1 practice question across 1 topic, including Hardware Security: Advanced Topics and Trends.

Field: Hardware Security: Advanced Topics and Trends

Try it: questions about Logic locking

Which correctly pairs techniques that protect semiconductor designs with the untrusted party each mainly assumes?

  1. ASplit manufacturing: users who bought the finished chip; IC camouflaging: the foundry that manufactures it; logic locking: the vendor of the design tools
  2. BSplit manufacturing: the foundry that manufactures it; IC camouflaging: those who read the circuit from chip images; logic locking: the foundry or those holding chips without the key
  3. CSplit manufacturing, IC camouflaging and logic locking all target only software viruses that get into the device
Show answer and explanation

Answer: B. Split manufacturing: the foundry that manufactures it; IC camouflaging: those who read the circuit from chip images; logic locking: the foundry or those holding chips without the key

In split manufacturing, the transistors and lower wiring layers (FEOL) are made at an external leading-edge foundry and the upper wiring layers at a trusted facility, so the external foundry cannot see the full connectivity of the circuit. IC camouflaging uses cells that look the same but have different functions, or fake contacts that only appear connected, to make reverse engineering that reads the circuit from images of a delayered chip harder, but it does not work against a foundry that holds the design data. Logic locking inserts gates whose function changes with a key and keeps the circuit from working correctly until the correct key is written after manufacturing, aiming to stop the foundry from stealing the design or producing extra chips. Since an attack was demonstrated in 2015 in which an adversary with a working chip compares inputs and outputs and narrows down the key with a SAT solver, research on schemes that resist it has continued.

Logic locking in the explanations

Questions that mention Logic locking (1)

  1. Which correctly pairs techniques that protect semiconductor designs with the untrusted party each mainly assumes?

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Related terms

Foundry Arm CCA (Confidential Compute Architecture) CHERI Confidential computing Control-flow integrity DICE (Device Identifier Composition Engine) FIPS 140-3 Hardware bill of materials (HBOM) Laser fault injection Memory Tagging Extension (MTE)

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