Security Threat Model & Mitigations
This is the threat model for the complete SENEX architecture. Mitigations that depend on the cryptographic stack (differential privacy, secure multi-party computation, zero-knowledge proofs) describe the target design, not v1.0-alpha behavior. What is enforced today: permissioned admission, signed and replay-protected messaging, governed/revocable neurolink sharing, full-node re-execution (block-style verification) with slashing of nodes that submit false results, and a bearer-token-protected local API.
THREAT 1: Data Poisoning Attacks
Attack: Malicious clients submit crafted gradients to degrade model performance
Mitigation:
- Byzantine-robust aggregation (Krum, Trimmed Mean, Median)
- Reputation system: Track contribution quality over time
- Outlier detection: Statistical tests on gradient distributions
- Slashing: Penalize validators who accept obvious poisoned data
THREAT 2: Model Inversion Attacks
Attack: Adversary attempts to reconstruct training data from model gradients
Mitigation:
- Differential privacy (target ε=1.0) is designed to provide provable protection
- Gradient clipping before noise addition (||g|| ≤ C)
- Secure aggregation prevents access to individual gradients
- Only aggregated updates available, never individual contributions
THREAT 3: Membership Inference Attacks
Attack: Determine if specific data point was in training set
Mitigation:
- Differential privacy is designed to fundamentally prevent this (target δ = 1e-6)
- Model checkpoints versioned, old versions retired
- Privacy budget tracking per client across all contributions
THREAT 4: Sybil Attacks
Attack: Single entity creates many fake identities to gain influence
Mitigation:
- Proof-of-Stake: Requires token stake for validator participation
- Identity verification for high-value contributors (optional tier)
- Reputation weighting: New contributors have lower influence
- Economic disincentive: Costs more to attack than potential gain
THREAT 5: Inference Attacks on Encrypted Data
Attack: Pattern analysis on encrypted communications or timing attacks
Mitigation:
- Mixnet/onion routing eliminates network-level tracking
- Randomized submission times (uniform distribution over time window)
- Dummy traffic to obscure real contributions
- Constant-time operations to prevent timing side-channels
THREAT 6: Malicious Validators
Attack: Compromised validators attempt to learn client data or manipulate results
Mitigation:
- MPC threshold: Requires ⌈2N/3⌉ honest validators (Byzantine fault tolerance)
- Secret sharing: No single validator sees complete information
- Slashing: Validators lose stake if caught cheating
- Verifiable computation: ZK proofs ensure correct execution
THREAT 7: Smart Contract Vulnerabilities
Attack: Exploit bugs in smart contracts to steal tokens or manipulate model
Mitigation:
- Formal verification of mission-critical contracts
- Multi-signature governance for contract upgrades
- Bug bounty program (10% of TVL reserved)
- Gradual rollout: Testnet → limited mainnet → full deployment
- Circuit breakers: Auto-pause on anomalous activity
THREAT 8: Collusion Between Clients and Validators
Attack: Coordinated attack to manipulate model or steal rewards
Mitigation:
- Economic game theory: Defection more profitable than cooperation
- Random validator assignment per aggregation round
- Reputation slashing for detected collusion patterns
- Whistleblower rewards from slashed stakes