What type of attacks occurs when a smartcard is operating under normal physical conditions, but
sensitive information is gained by examining the bytes going to and from the smartcard?

A.
Physical attacks.

B.
Logical attacks.

C.
Trojan Horse attacks.

D.
Social Engineering attacks.

Explanation:
Logical attacks occur when a smartcard is operating under normal physical conditions,
but sensitive information is gained by examining the bytes going to and from the
smartcard. One example is the so-called “timing attack” described by Paul Kocher. In
this attack, various byte patterns are sent to the card to be signed by the private
key. Information such as the time required to perform the operation and the number of
zeroes and ones in the input bytes are used to eventually obtain the private key. There
are logical countermeasures to this attack but not all smartcard manufacturers have
implemented them. This attack does require that the PIN to the card be known, so that
many private key operations can be performed on chosen input bytes.