Yonsei University

Seokjun Jang

Sungho Kang

A scan chain security circuit includes a scan chain including at least one flip-flop, a scan path obfuscator to obfuscate a path of a pattern sequence input to at least one first flip-flop grouped at an input side of the scan chain, in response to a first control signal, a scan path normalizer to normalize the path of the pattern sequence input to at least one second flip-flop grouped at an outside of the scan chain, in response to a second control signal, at least one dummy flip-flop interposed between the at least one first flip-flop and the at least one second flip-flop to receive a test key included in the pattern sequence, and a scan data obfuscator to damage and obfuscate an output pattern sequence output from the at least one second flip-flop, depending on whether a security key stored in a memory of a chip to be inspected is matched with the test key.

Scan chain security circuit and driving method thereof

Provided are scan device and method of diagnosing scan chain fault. The scan device for diagnosing a fault includes a scan partition including a plurality of scan chains which include path control scan flipflops connected to scan flipflops in cascade. In the scan partition, connection paths of the scan flipflops are controllable. The connection paths of the path control scan flipflops are controlled to detect a position of a fault such that a fault range in the scan partition is reduced to diagnose the fault.

Growing community of inventors

Seoul, South Korea

Seokjun Jang