# Security Model > **InterLink Chain is designed under the assumption that every component will be attacked — and engineers defenses at the protocol level so that the cost of attack always exceeds the potential reward.** *** ### Security Philosophy InterLink's security model is not an afterthought bolted onto a general-purpose architecture. It is **intrinsic to the network's design** — because InterLink handles real business revenue, real customer identities, and real tokenized assets. A security failure does not merely result in speculative token losses (as on most chains); it represents a direct attack on the economic infrastructure of verified businesses and their customers. The security architecture follows three principles: 1. **Defense in Depth** — No single layer is solely responsible for security. Identity, consensus, execution, and economic incentives create overlapping protection zones. 2. **Economic Rationality** — Every attack vector is analyzed through the lens of cost-versus-reward. The protocol is parameterized so that attacks are always economically irrational. 3. **Verifiable Guarantees** — Security properties are not mere claims. They are mathematically provable from the protocol's design parameters. *** ### Threat Model & Mitigation Matrix #### Layer 0: Identity-Level Threats | Threat | Description | Mitigation | Severity | | --------------------- | ------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------- | | **Sybil Attack** | Attacker creates thousands of fake identities to manipulate governance, drain airdrops, or dominate AMM pools | ZK-Biometric InterLink ID: 1 living human = 1 identity. No synthetic identity is possible without passing on-device biometric verification in the Secure Enclave. | 🔴 Critical — **Eliminated by design** | | **Identity Spoofing** | Attacker forges or steals another participant's InterLink ID | Biometric data never leaves the hardware Secure Enclave. ZK proofs are non-transferable and bound to device + biometric hash. Spoofing requires physical compromise of both the device hardware AND the biometric input. | 🔴 Critical — **Mitigated to hardware-attack level** | | **Identity Farming** | Attacker recruits real humans to create InterLink IDs and then controls their wallets | Economic incentive design: minimal value in fresh identities without genuine transaction history. Behavioral analysis at the application layer detects coordinated identity clusters. | 🟡 Medium | #### Layer 1: Consensus-Level Threats | Threat | Description | Mitigation | Severity | | --------------------------------- | -------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------- | | **Byzantine Validator (< 1/3)** | A minority of validators act maliciously — proposing invalid blocks, withholding votes, or attempting selective censorship | BFT consensus tolerates up to 1/3 Byzantine validators while maintaining both safety and liveness. Malicious proposals are rejected by honest supermajority. | 🟢 Tolerated by design | | **Byzantine Validator (≥ 1/3)** | An attacker controls 1/3 or more of the total validator stake | Network halts (liveness failure) but **does not produce invalid state** (safety preserved). Social consensus and governance mechanisms activate to resolve. Cost to acquire 1/3+ stake is economically prohibitive (see Economic Security below). | 🔴 Critical — **Economically prohibitive** | | **Double Signing (Equivocation)** | A validator signs two conflicting blocks at the same height, attempting to fork the chain | Automatic detection via consensus protocol. Immediate slashing (5–10% of stake) and permanent tombstoning. Cryptographic evidence published on-chain. | 🔴 Critical — **Punished automatically** | | **Long-Range Attack** | Attacker uses old validator keys to construct an alternative chain history | Mitigated by deterministic finality — there is no "longer chain" to switch to. Additionally, validator key rotation and weak subjectivity checkpoints prevent historical key reuse. | 🟡 Medium — **Mitigated by finality model** | | **Transaction Censorship** | A block producer deliberately excludes certain transactions | Round-robin proposer rotation ensures no single validator controls block production for consecutive rounds. Censored transactions are included by the next honest proposer within seconds. | 🟡 Medium — **Mitigated by rotation** | #### Layer 2: Execution & Economic Threats | Threat | Description | Mitigation | Severity | | ---------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------- | | **MEV Extraction (Front-running)** | Bots observe pending transactions and insert their own transactions before/after to extract value (sandwich attacks, front-running, back-running) | **InterLink ID gating** — all transactions require a verified identity. Bots cannot obtain InterLink IDs. Protocol-embedded AMM pools cannot be accessed by unverified addresses. Combined with fair transaction ordering within blocks. | 🔴 Critical — **Structurally eliminated** | | **Sandwich Attack on AMM** | Attacker places trades before and after a large swap to profit from price movement | Same as MEV: requires InterLink ID. Additionally, protocol-level slippage protection and minimum output enforcement at the AMM layer. | 🔴 Critical — **Eliminated** | | **Flash Loan Attack** | Attacker borrows large capital in a single transaction to manipulate AMM pricing, oracle readings, or governance votes | Protocol-embedded AMMs use time-weighted average pricing (TWAP) for oracle feeds, which cannot be manipulated by single-block flash loans. InterLink ID prevents the creation of anonymous attack contracts. | 🔴 Critical — **Mitigated** | | **Smart Contract Exploit** | Vulnerability in deployed contract code (reentrancy, integer overflow, access control failure) | Standard EVM security applies. InterLink provides: audited reference implementations, mandatory code verification for RWA contracts, and pre-compiled contracts for critical operations (reducing smart contract surface area). | 🟡 Medium — **Developer responsibility + protocol safeguards** | | **Oracle Manipulation** | Attacker manipulates price feeds to trigger unfavorable liquidations or trades | Protocol-embedded AMMs serve as native price oracles with TWAP smoothing. No dependency on external oracle networks for core protocol operations. | 🟡 Medium — **Mitigated by native oracles** | #### Network-Level Threats | Threat | Description | Mitigation | Severity | | ---------------------- | ------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------- | | **DDoS on Validators** | Attacker floods validator nodes with traffic to prevent block production | Rate limiting at the P2P layer, geographic distribution of validators, sentry node architecture (validators hidden behind relay nodes). Minimum stake-weighted identity requirement for peer connections. | 🟡 Medium | | **Eclipse Attack** | Attacker isolates a node from the honest network, feeding it false information | Minimum peer diversity requirements, persistent peer lists, and seed node bootstrapping from multiple independent sources. | 🟡 Medium | | **Network Partition** | Natural or adversarial network split isolating validator subsets | BFT safety guarantee: no partition with < 2/3 validators can produce a valid block. Network halts rather than forks — preserving safety at the cost of temporary liveness. | 🟡 Medium — **Safety preserved** | *** ### Consensus Security Analysis #### BFT Security Guarantees InterLink's BFT consensus provides **mathematically proven** security properties: **Safety Theorem:** ``` If fewer than 1/3 of validators (by stake weight) are Byzantine, then no two conflicting blocks can ever be committed at the same height. ``` **Liveness Theorem:** ``` If more than 2/3 of validators (by stake weight) are honest and connected, then the network will continue producing and finalizing blocks. ``` **Finality Guarantee:** ``` Once a block receives 2/3+ lock-confirmation signatures, it is final. No subsequent block, fork, or reorganization can alter it — regardless of future validator behavior. ``` #### Validator Set Security Budget The economic cost to compromise the network's safety is: ``` Cost of Safety Attack = 1/3 × Total Staked ITL × ITL Market Price Example at $100M total staked value: Cost to attack = $33.3M (minimum) Plus: Attacker's own staked ITL gets slashed upon detection Net cost = $33.3M + slashing penalty Potential reward = limited (deterministic finality prevents double-spend profit) ``` > **Key Insight:** Due to deterministic finality, a Byzantine attack cannot produce double-spend profits (unlike PoW chains where reorgs enable double-spending). The attacker can, at best, halt the network — which earns zero financial reward while costing 1/3+ of staked value. The attack is **economically irrational** at any meaningful stake level. *** ### Identity-Based Security: The InterLink ID Advantage InterLink's ZK-Biometric identity layer provides a security dimension that **no other blockchain possesses**: the structural guarantee that every on-chain actor is a verified, unique human being. #### How Identity Enhances Each Security Layer | Security Domain | Without Identity (Legacy Chains) | With InterLink ID | | ------------------------ | ------------------------------------------------------------ | ---------------------------------------------------------------------------------------- | | **MEV/Bot Protection** | Bots freely front-run transactions in public mempool | Bots cannot obtain InterLink ID → cannot submit transactions to identity-gated contracts | | **Governance Integrity** | Whale wallets dominate voting; Sybil rings amplify influence | 1-person-1-vote possible; governance weight can factor identity verification | | **Airdrop/Distribution** | Bot farms capture majority of distributions | Verified 1:1 distribution to unique participants | | **AMM Pool Safety** | Automated scripts extract value 24/7 | AMM interactions require verified identity; pools are protected by default | | **Spam Prevention** | Must rely on gas price to deter spam | Economic deterrent (gas) + identity deterrent (limited accounts per human) | #### Privacy-Preserving Security Critically, InterLink ID provides these security benefits **without compromising participant privacy**: * No personal data is stored on-chain or transmitted to any server * The ZK proof asserts only: *"this is a unique, living human who has not previously registered"* * The protocol knows WHO is verified (by wallet address) but not WHO they are (no PII linkage) * Participants retain full pseudonymity — their on-chain activity is not linked to their real-world identity *** ### Smart Contract Security Framework #### Protocol-Level Safeguards 1. **Pre-compiled Contracts for Critical Operations** — Core protocol functions (InterLink ID verification, AMM pool interaction, RWA token issuance) are implemented as pre-compiled contracts, not user-deployed Solidity. This eliminates entire classes of smart contract vulnerabilities for the protocol's most critical operations. 2. **Audited Reference Implementations** — InterLink provides officially audited contract templates for common use cases: * IRC-20 RWA token issuance * Paymaster for gasless transactions * Vesting contracts for token distribution * Multi-signature wallets 3. **Mandatory Verification for RWA Contracts** — All contracts that interact with the RWA engine (token issuance, value capture configuration, pool management) must be source-verified on the InterLink Explorer before activation. This ensures transparency and enables community review. #### Audit Pipeline | Phase | Description | | ------------------------- | ------------------------------------------------------------------------------------------------------------------------- | | **Internal Review** | All protocol-level contracts undergo internal peer review by the InterLink Labs engineering team | | **External Audit** | Independent audit by `[TBD — tier-1 audit firm(s)]` with public report publication | | **Formal Verification** | Critical modules (consensus interface, AMM pricing logic, identity verification) undergo formal mathematical verification | | **Bug Bounty** | Ongoing bug bounty program (see below) incentivizes responsible disclosure | | **Continuous Monitoring** | Real-time contract monitoring for anomalous state transitions post-deployment | #### Bug Bounty Program InterLink maintains a public bug bounty program to incentivize responsible security research: | Severity | Scope | Reward | | ------------ | ------------------------------------------------------------------- | ---------------------------- | | **Critical** | Consensus failure, unauthorized fund movement, identity bypass | Up to `[TBD]` USD equivalent | | **High** | AMM pricing manipulation, slashing logic bypass, governance exploit | Up to `[TBD]` USD equivalent | | **Medium** | DoS vectors, information disclosure, non-critical logic errors | Up to `[TBD]` USD equivalent | | **Low** | UI issues, non-exploitable edge cases | Up to `[TBD]` USD equivalent | *** ### Post-Quantum Security Roadmap As quantum computing advances toward cryptographic relevance, InterLink's security architecture is designed for **proactive migration** rather than reactive patching: #### Current Cryptographic Stack | Component | Algorithm | Quantum Status | | ------------------------ | ---------------------------- | -------------------------- | | **Transaction Signing** | ECDSA (secp256k1) | ⚠️ Vulnerable to quantum | | **Address Derivation** | Keccak-256 | ✅ Quantum-resistant (hash) | | **ZK Proofs (Identity)** | `[TBD — PLONK/Groth16/etc.]` | ⚠️ Depends on scheme | | **Consensus Signatures** | ECDSA / Ed25519 | ⚠️ Vulnerable to quantum | #### Migration Path | Phase | Action | Timeline | | -------------------------------- | -------------------------------------------------------------------------------- | ---------------------------------------------------- | | **Phase 1: Preparation** | Implement post-quantum signature verification as optional precompile | Pre-Mainnet | | **Phase 2: Hybrid Mode** | Support both classical and post-quantum signatures in parallel | Post-Mainnet Year 1 | | **Phase 3: Mandatory Migration** | Require post-quantum signatures for all new accounts and validator registrations | Triggered by NIST/industry quantum threat assessment | **Candidate Post-Quantum Algorithms:** * **CRYSTALS-Dilithium** — NIST-standardized lattice-based digital signatures (primary candidate) * **FALCON** — Compact lattice-based signatures (secondary candidate for resource-constrained environments) * **SPHINCS+** — Hash-based signatures (fallback — conservative, proven security assumptions) *** ### Incident Response Framework #### Severity Classification | Level | Definition | Response Time | Example | | ----------------- | ------------------------------------------------------- | -------------------- | ------------------------------------------------- | | **P0 — Critical** | Active exploit draining funds or compromising consensus | Immediate (< 1 hour) | AMM pool exploit, consensus halt | | **P1 — High** | Confirmed vulnerability with clear exploit path | < 4 hours | Smart contract logic flaw, identity bypass vector | | **P2 — Medium** | Potential vulnerability requiring investigation | < 24 hours | Unusual transaction patterns, validator anomaly | | **P3 — Low** | Minor issue with no immediate security impact | < 1 week | UI inconsistency, documentation gap | #### Response Protocol 1. **Detection** — Automated monitoring, community reports, or bug bounty submissions 2. **Triage** — Security team assesses severity and assigns classification 3. **Containment** — For P0/P1: emergency parameter adjustment via Foundation multi-sig if necessary 4. **Remediation** — Develop, audit, and deploy fix through appropriate governance channel 5. **Post-Mortem** — Public disclosure of root cause, timeline, and preventive measures #### Emergency Governance For P0-critical situations requiring immediate protocol intervention, the InterLink Foundation maintains a **multi-signature emergency mechanism** capable of: * Pausing specific contract interactions (not the entire chain) * Adjusting risk parameters (gas limits, AMM circuit breakers) * Triggering a pre-approved emergency upgrade This mechanism is: * Governed by a `[TBD]`-of-`[TBD]` multi-sig composed of Foundation members and external security advisors * Rate-limited (cannot execute more than one emergency action per 24-hour window without full governance vote) * Fully transparent — every emergency action is logged on-chain with justification * Time-bound — authority transfers to full on-chain governance as the network decentralizes > **Design Philosophy:** Emergency mechanisms exist to protect real business assets during the network's early maturation. As the validator set expands and governance matures, these mechanisms are progressively deprecated in favor of fully decentralized governance — with the ultimate goal of the Foundation having zero unilateral authority over protocol operations.