Cryptography for the Everyday Developer: Double Encryption and the Meet in the Middle Attack
This is an article in a series on Cryptography for the Everyday Developer. Follow along to learn the basics of modern cryptography and encryption. When the Data Encryption Standard (DES) was introduced in the 1970s, it was considered a solid block cipher. But DES has one major flaw by today’s standards — a small key space. With only 56 bits of key material, DES can be brute-forced with modern hardware by checking every possible key value. Once it was apparent that DES was no longer secure and could be brute-forced, a natural idea to extend the life of DES without resorting to an entirely new algorithm was to increase the size of the key space by encrypting the data twice with two different keys. The hope was that doubling the encryption operation with different keys would increase the difficulty of brute force attacks. ...