Integer factorization is the process of breaking down a composite number into its prime factors. A composite number is a positive integer that has at least one positive divisor other than one or itself. For example, the number 15 can be factored into the prime numbers 3 and 5, since 3 × 5 = 15. This process is fundamental in number theory and has applications in cryptography. The difficulty of integer factorization is the basis for the security of many encryption systems, such as those used in RSA encryption. While multiplying two large prime numbers is straightforward, finding those primes from their product becomes increasingly challenging as the numbers grow larger. This complexity is what makes integer factorization a critical area of study in mathematics and computer science.