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Cryptographic Key Protocol Comparison


🔐 Cryptographic Key Protocol Comparison

Symmetric Key Protocols

Name Type Key Length(s) Primary Use Standard / Notes
AES Symmetric 128 / 192 / 256 bits Data-at-rest encryption, VPNs, Wi-Fi (WPA2) NIST FIPS 197; very widely used
DES Symmetric 56 bits Legacy systems (deprecated) Obsolete; replaced by AES
3DES Symmetric 112 / 168 bits Legacy applications (banking, payments) Slow and being phased out
RC4 Symmetric 40–2048 bits Stream encryption (deprecated – insecure) Deprecated in TLS and WPA2
ChaCha20 Symmetric 256 bits Modern stream cipher, TLS, mobile devices Often used with Poly1305 MAC
Blowfish Symmetric 32–448 bits File and backup encryption Superseded by AES in most contexts
Twofish Symmetric Up to 256 bits AES finalist, still in use in some systems Slower than AES in some implementations

Asymmetric Key Protocols

Name Type Key Length(s) Primary Use Standard / Notes
RSA Asymmetric 1024 / 2048 / 3072 / 4096+ bits Digital signatures, key exchange, TLS, S/MIME PKCS#1 / FIPS 186-4
Diffie-Hellman (DH) Asymmetric 2048 / 3072 bits Secure key exchange (e.g. IPsec, TLS) Vulnerable if not using safe parameters
ECDH Asymmetric 224 / 256 / 384 / 521 bits Elliptic Curve Diffie-Hellman (key exchange) Faster and more secure than classic DH
ElGamal Asymmetric Variable Encryption, key exchange (less common today) Basis for some DSA variants
ECC Asymmetric 256 / 384 / 521 bits Encryption, key exchange, digital signatures Used in ECDSA, ECDH, EdDSA
DSA Asymmetric 1024–3072 bits Digital signatures (e.g. government systems) FIPS 186-4; often replaced by ECDSA
EdDSA (Ed25519) Asymmetric 256 bits High-performance signatures (modern TLS, SSH) RFC 8032; strong and efficient


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