January 8, 2002
Practical Aspects of Modern Cryptography
Karatsuba Multiplication
•
•
(A
x+
B)(C
x+
D) = AC
x
2
+ (AD+BC)
x
+ BD
•
4 multiplications, 1 addition
•
•
(A+B)(C+D) = AC
+ AD
+ BC
+ BD
•
(A+B)(C+D) – AC – BD = AD
+ BC
