Question

In what aspects is AES superior to DES? What are the disadvantages of AES compared to DES? Take into consideration factors such as efficiency, complexity, scalability, flexibility, computational needs, security, resistance to attacks, etc.

Answer 1

Advanced Encryption Standard (AES) is superior to Data Encryption Standard (DES) in the following aspects, and also the disadvantages of AES compared to DES are because of the same reasons:

* From the security perspective, DES proves to be not adequately secure, whereas AES is considered to be secure or provides excellent and strong security.
* From the complexity, compatibility, or supportability perspective, DES is less complex the key length it supports and uses is 56 bits, whereas AES is complex supporting and uses 128, 192, or 256 bits. Also, with respect to block size, DES supports 64 bits plaintext, where AES 128, 192, or 256 bits plaintext.
* The above compatibility factor can also be considered as a flexibility factor which DES has less, where AES being more flexible.
* From the resistance to attacks perspective, DES is less or has no cryptanalysis resistant being vulnerable to differential and linear cryptanalysis and has weak substitution tables, whereas AES is more cryptanalysis resistant being strong standing against, defending, fighting, resisting, and protecting from differential, truncated differential, linear, interpolation, and square threats and attacks.
* Flexibility factor from the section process aspect, in DES, it is secret, whereas, in AES, it is secret as well, however, it accepts open public comment.
* From speed, especially from the performance perspective, DES is slow, whereas AES is fast.
* From the scalability factor perspective, DES is scalable, where AES is not.
* From the efficiency (performance) factor perspective, DES is medium-fast in encryption and decryption time, whereas AES is fast.
* Again from efficiency (performance) and also computation needs factor perspective, with respect to power utilization, consumption, and cost, DES and AES, both use less power.
* From the hardware and software implementation perspective, DES is better in hardware than software, whereas AES is fast and better in both.
* In terms of complexity in algorithm structure, DES has and works on Feistel network, whereas AES has and works on substitution permutation network. DES has a smaller key size than AES, and because of this, it makes DES less secure than AES.
* In terms of security, vulnerability, and resistance to attacks, DES is vulnerable to brute force attacks, whereas AES is vulnerable to side-channel attacks.
* From the computational needs factor perspective, DES functions on only 2^56 possible keys, whereas AES functions with 2^128, 2^192, or 2^256.
* Their computational needs are, DES requires 95^7 possible ASCII printable character keys, whereas AES requires 95^16, 95^24, or 95^52
* From security, time, and speed factors perspectives, DES requires a time of 400 days for a 56-bit key to check all possible keys at 50 billion keys per second, whereas AES requires a time of 5*10^21 years for a 128-bit key to check all possible keys at 50 billion keys per second.