Symmetric Encryption
Definition
Symmetric encryption uses the same key for both encryption and decryption. AES, ChaCha20, and other symmetric algorithms are inherently more quantum-resistant than public-key cryptography—Grover's algorithm provides only quadratic speedup, easily addressed by doubling key lengths.
Technical Explanation
Symmetric encryption operates differently than public-key systems. Both parties share a secret key; no public/private pair exists. The challenge is key distribution—how do parties establish a shared secret? This is where key encapsulation mechanisms (KEMs) like Kyber become essential.
Quantum impact: Grover's algorithm searches for keys quadratically faster—256-bit keys have 128-bit quantum security. This contrasts with public-key cryptography where Shor's algorithm provides exponential speedup, completely breaking RSA/ECDSA. Symmetric cryptography survives with larger keys.
SynX Relevance
SynX's cryptographic architecture combines quantum-resistant key encapsulation (Kyber-768) with symmetric encryption (AES-256/ChaCha20). Kyber establishes shared secrets; symmetric algorithms encrypt bulk data. This hybrid approach provides efficiency and quantum resistance throughout.
Frequently Asked Questions
- Why not just use symmetric encryption for everything?
- Key distribution is the problem—how to share keys without meeting. KEMs solve this.
- Is ChaCha20 quantum-safe?
- Yes—with 256-bit keys, ChaCha20 provides adequate quantum security like AES-256.
- Should I use longer symmetric keys?
- 256 bits is sufficient; larger keys waste resources without meaningful security gain.
Efficient symmetric encryption with quantum-safe key exchange. Complete security with SynX