Why is AES preferred over 3DES and DES?

AES is preferred over 3DES and DES for a mix of security, performance, and future-proofing reasons. Here’s the breakdown in plain terms:

1. Much stronger security

• DES uses a 56-bit key, which is far too small today. It can be brute-forced in hours (or less) with modern hardware.

• 3DES improves this by applying DES three times, but its effective security is only about 112 bits, and it has known weaknesses related to its design.

• AES supports 128-, 192-, and 256-bit keys, making brute-force attacks completely impractical with current and foreseeable computing power.

2. Faster and more efficient

• DES and 3DES are slow in software and inefficient on modern CPUs.

• 3DES is especially slow because it runs DES three times.

• AES was designed for efficiency and is much faster, especially with hardware acceleration (like Intel’s AES-NI), making it ideal for high-throughput systems.

3. Better design for modern cryptography

• DES/3DES are based on an older Feistel network structure.

• AES uses a substitution–permutation network, which is more resistant to known cryptanalytic attacks and easier to analyze securely.

4. No practical attacks when used correctly

• DES is broken.

• 3DES is deprecated and vulnerable to attacks like Sweet32 (birthday attacks due to its small 64-bit block size).

• AES has no practical attacks against it when implemented with secure modes (like GCM or CBC with proper padding and IVs).

5. Larger block size

• DES and 3DES use a 64-bit block size, which increases the risk of data collisions in large datasets.

• AES uses a 128-bit block size, which is far safer for encrypting large volumes of data.

6. Industry and standards support

• AES is the current standard approved by NIST and is required or recommended in most modern security protocols (TLS, IPsec, WPA3, disk encryption).

• DES is obsolete.

• 3DES is officially deprecated and being phased out worldwide.