In this research, we study primality testing of arbitrary integers via
number theory, randomized algorithms and optimization theories.
Concerning fundamentals of modern cryptography, we focus on the
cryptanalysis, cryptosystems and RSA keys, which are widely used in
secure communications, e.g., banking systems and other platforms with an
online security. For a given n-bit integer N, our consideration is
realized as a decision problem, viz. an optimized algorithm rendering
the output YES, if N is a prime, and NO otherwise. In order to design
such an algorithm, we begin by examining essential ingredients from the
number theory, namely, divisibility, modular arithmetic, integer
representations, distributions of primes, primality testing algorithms,
greatest common divisor, least common multiplication, pseudoprimes,
Np-hard discrete logarithm problem, residues and others. Hereby, we give
special attention to the congruence relations, Chinese remainder theorem
and Fermat's little theorem towards the optimal primality testing of an
integer. Finally, we anticipate optimized characterizations of
Cunningham numbers in the light of randomization theory and their
applications to cryptography.