Product cipher facts for kids
Product ciphers usually consist of iterations of several rounds of the same algorithm. While individual rounds are not themselves secure, it is hoped that a sufficiently long chain of rounds would load the cipher with sufficient confusion and diffusion properties as to make it resistant to cryptanalysis.
A product cipher that uses only substitutions and permutations is called a SP-network. Feistel ciphers are another important class of product ciphers.
Product cipher Facts for Kids. Kiddle Encyclopedia.