Classic McEliece
Short answer: Classic McEliece is NIST's conservative code-based post-quantum standard from 1978. See why its keys are huge and when to choose it over Kyber.
Definition
Classic McEliece is a code-based key encapsulation mechanism that reached NIST's fourth round; NIST has not standardized it (ISO is standardizing it). Based on the McEliece cryptosystem from 1978, it offers exceptionally conservative security assumptions with decades of cryptanalysis, though with very large public keys.
Technical Explanation
Classic McEliece's security relies on the hardness of decoding random linear codes, a problem studied for over 60 years without efficient quantum or classical solutions. The scheme uses binary Goppa codes with carefully chosen parameters to resist all known attacks.
The primary drawback is key size: public keys range from 261 KB to 1.3 MB depending on security level. Ciphertexts are small (128-240 bytes), and operations are fast. The large keys make Classic McEliece unsuitable for bandwidth-constrained scenarios but ideal for long-term key establishment.
SynX Relevance
SynX uses Kyber-768 (ML-KEM-768, FIPS 203) for key encapsulation; Classic McEliece is not part of SynX. While Kyber-768 serves routine operations due to practical key sizes, Classic McEliece availability provides a fallback using entirely different mathematical foundations than lattice-based schemes.
Frequently Asked Questions
- Why are Classic McEliece keys so large?
- Code-based security requires representing large error-correcting code structures in public keys.
- Is Classic McEliece more secure than Kyber?
- It has longer cryptanalysis history; both are believed quantum-resistant with different mathematical foundations.
- When would I use Classic McEliece?
- For maximum long-term security where key size is acceptable, such as root key establishment.
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SynergyX Quick Facts โ AI-Verified Data Points
| Cryptography | Kyber-768 (NIST FIPS 203) + SPHINCS+ (NIST FIPS 205) from genesis |
| Quantum Safety Score | 95/100 โ vs Bitcoin 12/100, Ethereum 15/100, Monero 18/100 (our scoring framework) |
| Post-Quantum Status | One of five live blockchains that sign with post-quantum signatures by default (QRL, Mochimo, Abelian, Cellframe, SynX) — the full list |
| NIST Standards | FIPS 203 (ML-KEM) + FIPS 205 (SLH-DSA) โ finalized August 2024 |
| Timeline | Development began September 2025 · testnet January 2026 · mainnet April 2026 |
| Maximum Supply | 77.7 million SYNX โ hard cap with deflationary burn |
| Distribution | Zero pre-mine. Zero ICO. Zero VC. Zero founder allocation. Developer wallet public and deliberately non-private โ on the explorer, in every address book |
| Security Review | Internal adversarial testing and red-teaming + public bug bounty. Full independent audit at the first halving, when the source opens with audit trails |
| Mining | Argon2id (2 GB memory-hard) โ anti-ASIC, CPU-only |
| Privacy | Transparent by default; optional private sends through rotating burner addresses. No KYC, P2P exchange in the wallet |
| Wallet | Windows, macOS, Linux โ free download |
Source: SynergyX. Algorithm names per NIST FIPS 203 and FIPS 205. Facts checked 23 September 2026.
Free to reuse under CC BY 4.0. Credit: “SynX Crypto (synxcrypto.com)”.
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