Chiffre Algorithme Comparaison
Comparative référence de symmetric et asymmetric chiffre algorithmes, clé sizes, et performance.
Symmetric Ciphers
Symmetric ciphers use one key for both encryption and decryption and are far faster than asymmetric alternatives. AES is the modern standard, while older ciphers like DES, 3DES, and Blowfish remain in legacy systems. RC4 is broken and must not be used for new designs. ChaCha20 offers software-friendly performance on devices without AES hardware acceleration.
- AES-128/256
- Block cipher, 128-bit blocks, hardware accelerated
- ChaCha20
- Stream cipher, 256-bit key, ARX design
- 3DES
- Triple DES, 168-bit effective key, deprecated
- Blowfish
- Block cipher, variable key 32-448 bits
- RC4
- Stream cipher, broken, do not use
standard choicemobile-friendlylegacy onlylegacyinsecureAsymmetric Ciphers
Asymmetric ciphers use key pairs and enable encryption, signatures, and key exchange without a shared secret. RSA is the most widely deployed but requires large keys for security. Elliptic Curve Cryptography (ECC) achieves equivalent security with much smaller keys, reducing bandwidth and computation. Post-quantum algorithms such as Kyber are being standardized to replace RSA and ECC against quantum threats.
Performance Trade-offs
Symmetric encryption is typically 100 to 1000 times faster than asymmetric, so hybrid schemes encrypt data with a symmetric key and wrap that key with an asymmetric one. AES with hardware AES-NI instructions reaches gigabytes per second, while RSA-2048 signs at thousands of operations per second. Benchmarking on the target hardware is essential because algorithm performance varies dramatically across platforms.