Overview:
The Data Encryption Standard, or DES for short, is a symmetric-key block cipher designed by IBM and published by the National Institute of Standards and Technology (NIST). The plaintext is broken into blocks of 64-bits and encryption is performed block-wise. This means that the cryptographic key and the algorithm are applied to it together rather than one bit at a time. The encryption process consists of 16 rounds and each block is encrypted using a key to a cipher-text (64-bits) by using permutations and combinations. They key used in DES has 56-bits as a functional key while the rest 8 bits are for parity checking.
DES was actually the first encryption algorithm approved by the US government for public disclosure. It is now insecure due to its small key size – it is vulnerable to a brute force attack.
Developer's QuickStart
IT Admin's QuickStart
Manager's QuickStart
Attacks:
- 1. Brute Force attacks are common since the key length is mall for DES (64 bits).
- 2. Differential Cryptanalysis can break full 16-round DES by using 247 chosen plaintext.
- 3. A man-in-the-middle attack requires complexity of 232 to break 6-round DES.
- 4. Linear cryptanalysis can break DES using 243 known plaintext
- 5. A combination of linear and differential cryptanalysis called ‘differential-linear’ cryptanalysis can also break DES depending on how many rounds
- 6. Davies Attack (DA) can break DES with 250 known plaintext.