‘Cryptography: the secret life of primes’ shows how prime numbers can be used to encrypt sensitive data. All info can be communicated as numbers through computer systems, and cryptography simply masks these numbers with other numbers. A simple cryptography system involves both parties exchanging keys, but this exchange is not necessary when using numbers and their prime factors as keys. The sending party determines the remainder of the division of two huge numbers in order to encrypt the data. The receiving party can then use the Euclidean algorithm and Euler theorem to decrypt the data. These systems use such large numbers that computers cannot crack these codes quickly.