Preventing Scan-Based Side-Channel Attacks by Scan Obfuscating with a Configurable Shift Register

Table 6

Comparison of different secure scan design. Note: LOC denotes “launch-on-capture.”

Design	Area overhead (%)	Vulnerability	Probability of brute force	Test application
Proposed (64 bit authorization code)	0.18	None	2^−64(64 is the length of test authorization code)	All types of tests can be applied
MKR [30]	0.19	None	Brute force is inapplicable	Online testing cannot be applied
Mode reset [49]	∼10	Test-mode-only attacks	Brute force is inapplicable	Online testing cannot be applied
Scan chain encryption [40]	2.92	Memory attack	2^−m(m is the length of test password)	All types of tests can be applied
FTSL-64 [59]	3.09	None	2^–64	Loc delay testing cannot be applied