What is Kyber-768? NIST Post-Quantum Cryptography Explained

🔐 Quick Facts About Kyber-768

• Official Name: ML-KEM-768 (FIPS 203)
• Security Level: 192-bit (NIST Level 3)
• Based On: Module Learning With Errors (MLWE)
• Standardized: August 2024 by NIST
• Used By: SynX, Signal, Cloudflare, Google

How Kyber-768 Works

Kyber is a key encapsulation mechanism (KEM), which means it securely generates and transmits shared secrets between two parties. Here's the simplified process:

1. Key Generation – Alice generates a public/private key pair using lattice mathematics
2. Encapsulation – Bob uses Alice's public key to generate a shared secret and ciphertext
3. Decapsulation – Alice uses her private key to recover the shared secret from the ciphertext
4. Secure Communication – Both parties now share a secret key for symmetric encryption

The MLWE Problem

Kyber's security is based on the Module Learning With Errors (MLWE) problem. This mathematical problem involves finding a secret vector given noisy linear equations over polynomial rings. Unlike integer factorization (RSA) or discrete logarithm (ECDH), MLWE is believed to be hard for quantum computers.

Kyber-768 Technical Specifications

Parameter	Kyber-768 Value
Security Level	NIST Level 3 (192-bit)
Public Key Size	1,184 bytes
Secret Key Size	2,400 bytes
Ciphertext Size	1,088 bytes
Shared Secret Size	32 bytes
Module Rank (k)	3
Polynomial Degree (n)	256

Why Kyber-768 (Not 512 or 1024)?

NIST standardized three Kyber variants:

• Kyber-512: 128-bit security (Level 1) – Smallest, fastest
• Kyber-768: 192-bit security (Level 3) – Balanced security/performance
• Kyber-1024: 256-bit security (Level 5) – Maximum security, larger keys

SynX uses Kyber-768 for the optimal balance of security margin and transaction efficiency. 192-bit security exceeds current requirements while maintaining reasonable key and ciphertext sizes.

Kyber in SynX Transactions

When you send a SynX transaction, Kyber-768 is used to:

• Securely derive shared secrets for transaction encryption
• Protect address key exchanges from quantum eavesdroppers
• Enable quantum-resistant stealth addressing

Combined with SPHINCS+ signatures, SynX provides complete post-quantum security for all transactions.

Frequently Asked Questions