Symmetric Cryptography

Data Encryption Standard (DES)

An older block cipher using a 56-bit key. It has been largely replaced due to its vulnerability to brute-force attacks.

Triple DES (3DES)

Applies DES encryption three times with different keys to strengthen security; however, it is slower and being phased out.

Advanced Encryption Standard (AES)

The most widely used symmetric encryption today; a block cipher with key sizes of 128, 192, and 256 bits. It is fast, secure, and adopted as a U.S. federal standard.

Blowfish

Operates on 64-bit blocks and supports variable key lengths from 32 to 448 bits. It is known for its simplicity and faster encryption/decryption speed, making it suitable for smaller data or limited resource environments. However, its smaller block size can be a security limitation for large data volumes.

Twofish

Operates on larger 128-bit blocks with fixed key sizes of 128, 192, or 256 bits. It offers stronger security and resistance to cryptanalytic attacks due to its complex design combining substitution-permutation and Feistel networks. Twofish is more efficient for encrypting large datasets and provides better protection against advanced attacks. Its design aims for flexibility and robustness, ideal for modern applications needing high confidentiality.

RC4

A stream cipher, meaning it encrypts data one byte at a time rather than in chunks. It is famous for its simplicity and speed in software. It was once the most widely used software stream cipher (used in WEP for WiFi and SSL/TLS), but multiple vulnerabilities were discovered, rendering it insecure for modern use. Key sizes typically vary between 40 and 2048 bits.

RC5

A parameterized block cipher, which means the user can select the block size, key size, and number of rounds (passes) based on their security needs. It is notable for introducing "data-dependent rotations," where the data is shifted by an amount determined by the data itself, making it resistant to certain types of crypto-analysis. Block sizes between 32, 64, or 128 bits with key sizes varying between 0 to 2040 bits.

RC6

An improvement of previous generations designed for the AES competition. It operates on 128-bit blocks with 128, 192, or 256-bit keys and introduces integer multiplication and uses four working registers instead of two.

ChaCha20

A high-speed stream cipher built to be secure and efficient, especially in software without specialized hardware (like on mobile phones). It operates by generating a "keystream" in 512-bit blocks which is then combined (XORed) with your data. With a key size of 256 bits. It is the spiritual successor to RC4: it is fast and simple like RC4, but unlike RC4, it is highly secure.