Security Model
13.1 Non-Custodial Foundation
The primary security property of SwapBlok is mathematical non-custody at two independent layers. For SB Chain interactions, the dfns.io MPC-TSS architecture (Section 6) means no signing capability exists outside the user's device. For external chain interactions, the ika.xyz 2MPC dWallet architecture (Section 5.2) does the same at the bridge layer. The largest class of exchange security failures (key theft, insider misappropriation, regulatory seizure of exchange keys) are structurally impossible because no exchange-held key exists to seize.
13.2 Consensus Security
RDPoS with commit-reveal randomisation requires an adversary to control a majority of the 63-node candidate pool to influence block production. The random selection of 21 active producers per round means that even controlling 22 of 63 nodes does not guarantee inclusion in any specific round. The economic cost of accumulating sufficient SBT to dominate the vote while maintaining 32+ operational nodes simultaneously creates a prohibitive barrier to attack.
13.3 Bridge Security
sBridge security rests on three independent layers:
- 2MPC: requires user co-signature for every release; cannot be bypassed by any operational key
- Merkle proof verification: SB Chain verifies proofs independently; the relayer cannot fabricate valid proofs
- Confirmation depths: chain reorganisation attacks are economically infeasible at the required confirmation depths
13.4 Smart Contract Risk
SB Chain's core logic is implemented in C++ as part of the chain's consensus code, not as smart contracts. This eliminates the smart contract vulnerability class (reentrancy, integer overflow, logic errors in Solidity/Rust) that has been responsible for the majority of DeFi losses.
External chain bridge contracts (on Ethereum, Tron) are minimal in scope, handling only lock and unlock logic, reducing attack surface.
13.5 Audit Programme
SB Chain's core code, sBridge contracts, dfns.io wallet integration, and ika.xyz dWallet integration are subject to independent security audits prior to mainnet launch. Audit reports will be published publicly. A bug bounty programme will be established at testnet launch.