Which of the following types of cryptography should be used when minimal overhead is necessary for a
mobile device?

A.
Block cipher

B.
Elliptical curve cryptography

C.
Diffie-Hellman algorithm

D.
Stream cipher

Explanation:
Regarding the performance of ECC applications on various mobile devices, ECC is the most suitable PKC
(Public-key cryptography) scheme for use in a constrained environment.
Note: Elliptic curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic
structure of elliptic curves over finite fields. One of the main benefits in comparison with non-ECC
cryptography (with plain Galois fields as a basis) is the same level of security provided by keys of smaller
size. Using smaller key size would be faster.
Incorrect Answers:
A, D: Block cipher and stream cipher are cryptography subtypes.’=
C: Diffie-Hellman would require longer keys which would increase overhead.
Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis,
2014, pp. 245-246, 253
http://www.studymode.com/essays/Elliptic-Curve-Cryptography-And-Its-Applications-1560318.html
http://en.wikipedia.org/wiki/Elliptic_curve_cryptography