The identification of credit card encoders by hierarchical cluster analysis of the jitters of magnetic stripes.
The relative bit density variation graphs of 207 specimen credit cards processed by 12 encoding machines were examined first visually, and then classified by means of hierarchical cluster analysis. Twenty-nine credit cards being treated as 'questioned' samples were tested by way of cluster analysis against 'controls' derived from known encoders. It was found that hierarchical cluster analysis provided a high accuracy of identification with all 29 'questioned' samples classified correctly. On the other hand, although visual comparison of jitter graphs was less discriminating, it was nevertheless capable of giving a reasonably accurate result.
Leung
S C
SC
Forensic Science Division, Government Laboratory, Kowloon, Hong Kong, China.
Fung
W K
WK
Wong
K H
KH
D016000:Cluster Analysis; D005554:Forensic Medicine / Q000379:methods*; D005607:Fraud; D006801:Humans; D008280:Magnetics