To address the vulnerabilities of DES without completely discarding its proven architecture, the industry introduced Triple DES (3DES). Instead of creating a new algorithm from scratch, 3DES applies the DES cipher three times to each data block. It typically uses three 56-bit keys (K1, K2, and K3) in an encrypt-decrypt-encrypt (EDE) sequence.
While 3DES fixed the security issues of its predecessor, it introduced a new problem: performance. Because it runs the DES algorithm three times, it is significantly slower than more modern ciphers. Furthermore, its 64-bit block size eventually became a liability against certain types of cryptanalysis (such as "Sweet32" attacks).
Developed in the early 1970s by IBM and adopted as a federal standard in 1977, DES was the first widely used encryption algorithm. It is a symmetric-key block cipher that operates on 64-bit blocks of data using a 56-bit key. Its structure is based on a Feistel network, which involves 16 rounds of substitution and permutation. At the time, DES was a breakthrough, offering a standardized way for government agencies and financial institutions to secure digital communications.
Despite its architectural brilliance, DES had a fundamental flaw: its key length. A 56-bit key offers 2562 to the 56th power
