Data Encryption Standard (DES)

A symmetric encryption algorithm used to secure data, now considered outdated.

Understanding DES

DES follows a Feistel cipher structure, meaning it divides plaintext into two halves and applies encryption operations repeatedly. The algorithm consists of:

Initial Permutation (IP) – Rearranges bits to enhance diffusion.
16 Rounds of Encryption – Includes substitution, permutation, and XOR operations with round keys.
Final Permutation (FP) – Reverses the initial permutation, producing the final ciphertext.

Common Applications of DES (Historical Use)

Banking & Financial Transactions – Used to encrypt ATM PINs and credit card data.
Secure Communications – Previously used in military and government encryption.

Data Storage Protection – Employed for disk encryption and secure file storage.

Challenges and Considerations

Vulnerability to Brute-Force Attacks – Modern computing can break a 56-bit key in hours.
Regulatory Non-Compliance – DES is no longer FIPS 140-2 compliant.
Performance Overhead – Triple DES (3DES), an improved version of DES, is slower than AES.