Technical Architecture

Seven-Layer Infrastructure Stack

Proof-of-Generation (PoG)

Unlike PoW/PoS traditional mining. Generation is proof.

• ≥3 independent Oracles cross-verify
• Deviation > 5%: slashing of staked Key Coin
• Upon verification: PoG-NFT minted, recording kWh, timestamp, geolocation, AI output

AI Contribution Assessment

Core Formula:

$V^t = \sum_{i} w_i \times (e_i^t \times c_i^t)$

90-99% Approval Mechanism

Multi-round voting → proposal iteration → converging toward consensus. Eliminates 51% tyranny-of-the-majority.

Contract Architecture

Post-Quantum Cryptography (PQC) Technical Architecture

Key Coin solemnly commits: complete network-wide PQC migration before quantum computers pose a material threat to ECDSA. This commitment is irrevocable and enshrined in the QuantumMigrationCommitment contract.

Threat Model

Quantum computers threaten blockchains from three directions:

Shor's Algorithm — The Asymmetric Crypto Terminator

Shor's algorithm breaks the mathematical foundations of RSA and ECDSA in polynomial time. Ethereum's secp256k1 curve is defenseless against a sufficiently fault-tolerant quantum computer.

$N = p \times q \quad\rightarrow\quad f(x) = a^x \bmod N \quad\rightarrow\quad \text{QFT finds period } r \quad\rightarrow\quad p,q = \gcd(a^{r/2} \pm 1, N)$

Grover's Algorithm — The Symmetric Crypto Weakening

Grover's algorithm reduces brute-force search complexity from $O(N)$ to $O(\sqrt{N})$. Keccak-256's preimage resistance drops from 256-bit to 128-bit. Countermeasure: extend hash output to 384-bit or use SHAKE-256 directly.

HNDL (Harvest Now, Decrypt Later) — The Most Urgent Threat

Attackers intercept and store encrypted transaction data today, decrypting it once quantum computers mature. Even if quantum computers are 5-10 years away, data requiring long-term confidentiality is already at risk.

NIST Standardization Landscape

NIST launched the global PQC algorithm competition in 2016. On August 13, 2024, the first three FIPS standards were officially published:

In March 2025, NIST selected the code-based algorithm HQC for additional KEM standardization, achieving a "lattice + code + hash" triangulation.

Global Migration Timeline Consensus

Algorithm Families

Lattice-Based — The Workhorse

Security relies on SVP (Shortest Vector Problem) and CVP (Closest Vector Problem) in high-dimensional lattices, both NP-hard.

ML-KEM (Kyber) — Key Encapsulation

Built on the Module-LWE problem. Intuition: given many "noisy" linear equations $A \cdot s + e = b$, recovering the secret vector $s$ from $b$ is hard in both classical and quantum settings.

Process:

1. Key Generation: random matrix $A$ + small secret vector $s$ → public key $(A, t = A \cdot s + e)$
2. Encapsulation: encrypt with $r$ → ciphertext $(u, v)$ → derive shared key
3. Decapsulation: recover shared key from ciphertext using $s$ (leverages bounded error correction)

Performance benchmark: 6000 encapsulations/sec, 3500 key pairs/sec.

ML-DSA (Dilithium) — Digital Signature

Adopts the Fiat-Shamir with Aborts paradigm. If the response vector $z$ coefficient is too large during signing, "abort" and retry, preventing secret vector distribution leakage.

Key feature: supports batch signature verification — in "single key + multiple messages" scenarios, 20%-50% faster than per-message verification.

Performance benchmark: 1000 signatures/sec, 3000 verifications/sec.

Hash-Based — The Conservative Backup

SLH-DSA (SPHINCS+) depends only on hash function collision resistance, making it the most conservative security assumption.

Structure: WOTS+ one-time signatures → Merkle Tree aggregation → Hypertree multi-layer nesting.

Trade-off: signature size 8-50 KB (vs ECDSA's 64 bytes, Dilithium's ~2.4 KB), signing speed 1-2 orders of magnitude slower. Used only as backup in high-frequency TLS handshakes.

Code-Based — Diversity Assurance

HQC is based on the syndrome decoding problem (NP-complete), having withstood 40+ years of cryptanalysis since the original McEliece scheme in 1978. NIST selected it as Kyber's "mathematically distinct" backup — should a theoretical breakthrough compromise lattice-based cryptography, HQC provides an escape path.

Key Coin PQC Migration Architecture

Hybrid Signature Mode — The Transition Core

Key Coin employs Hybrid AND mode (not OR):

$\text{Valid Signature} = \text{ECDSA}(secp256k1) \text{ verifies } \mathbf{AND} \text{ ML-DSA}(Dilithium) \text{ verifies}$

Not "either/or" — both must pass to be valid. Prevents attackers from downgrading to ECDSA-only weak mode.

Crypto-Agility Design

Core principle: algorithm selection decoupled from business logic. Never hard-code algorithms in contracts.

// ❌ Hard-coded — unacceptable
require(ecrecover(hash, v, r, s) == signer, "invalid")

// ✅ Crypto-agile — upgradeable
interface ISignatureVerifier {
    function verify(bytes32 hash, bytes calldata signature, address claimedSigner)
        external view returns (bool);
}

Verifier contracts are pluggable: ECDSAVerifier → HybridVerifier → DilithiumVerifier, with zero changes to business contracts.

Five-Tier Threat Response Mechanism

Escalation Flow

Each tier change requires:

1. ≥ 3 quantum security expert committee members' multi-sig confirmation
2. IPFS evidence link attached (academic papers, NIST bulletins, industry reports)
3. On-chain event permanently recorded

Key & Signature Size Comparison

Side-Channel Attacks & Fault Injection Defense

Mathematical security of PQC algorithms ≠ physical implementation security. High-performance implementations (e.g., NTT number theoretic transform) may leak secrets through power consumption, timing, or electromagnetic radiation.

Known Attack Vectors

Key Coin Defense Strategy

User Migration Flow

THREAT = 0-1 (Current): Normal ECDSA usage, no action required
    ↓
THREAT = 2 (CONCERNED): Generate Dilithium key pair → register PQC public key hash on-chain → system auto-enables hybrid signing, zero friction
    ↓
THREAT = 3 (CRITICAL): 90-day countdown begins, all high-value TX must use hybrid signing, non-migrated → frozen

PQC Public Key Registration TX: registerPQCKey(bytes32 pqcPubKeyHash)

• Only submit public key hash (32 bytes), minimal on-chain storage overhead
• After registration, address binds both ECDSA public key (implicit, i.e., address) and PQC public key hash
• Updatable (72-hour timelock to prevent hijacking)

On-Chain Contract Architecture

QuantumMigrationCommitment Core Interface:

interface IQuantumMigrationCommitment {
    function currentThreatLevel() external view returns (uint8);
    function upgradeThreatLevel(uint8 newLevel, string calldata evidenceIPFS) external;
    function migrationDeadline() external view returns (uint256);
    function registerPQCKey(bytes32 pqcPubKeyHash) external;
    function pqcKeyRegistered(address user) external view returns (bool, bytes32);
    function verifyHybrid(bytes32 hash, bytes calldata ecdsaSig, bytes calldata pqcSig, address claimedSigner) external view returns (bool);
}

Current on-chain data: threat level = 2 (CONCERNED) ✅

Global Standards Alignment