Specifications

Smart Cards Lab COMPGA12 University College London
T ms: 31.210
APDU: FF8800006000
Resp: (90 00)
T ms: 62.759
In contrast, if the key is wrong, the second command takes much longer:
APDU: FF82200006FFFFFF000000
Resp: (90 00)
T ms: 31.779
APDU: FF8800006000
Resp: (90 00)
T ms: 136.417
Thus somebody that does not have the access to the USB port commu-
nications but only to their timing, can infer some information with certainty
(for example if the result of some cryptographic check is correct or not).
c
Nicolas T. Courtois 2009-10