sBridge

Overview

Trustless cross-chain bridge with 2MPC dWallets, permissionless relayers, and no custodians

SBChain is a self-contained blockchain — its native assets (BTS and on-chain tokens) exist entirely within the protocol. sBridge is the mechanism by which external assets from other blockchains (Bitcoin, Ethereum, Solana, Tron, and SBChain) are brought onto SBChain and made tradeable on the DEX, without any custodian.

Over $3.6 billion has been lost to bridge hacks since 2021. In nearly every case, the root cause was the same: a small set of parties held enough key material to be compromised. sBridge eliminates this attack surface by making unilateral signing cryptographically impossible.

SBChain provides the on-chain primitives that sBridge is built on. The bridge combines three protocol components: the gateway/IOU model, Hash Time Locked Contracts (HTLC), and Withdrawal Permissions. On top of these, 2MPC dWallets provide trustless key management and permissionless relayers handle censorship-resistant proof delivery. No single party, including SwapBlok, can move funds unilaterally.

Bridge Fee

sBridge charges a flat 0.10% protocol fee on deposits only — assets bridging into SB Chain. Bridging 1 ETH credits 0.999 wETH to your account; 0.001 wETH flows to the SwapBlok treasury. Withdrawals are free — there is no protocol fee when bridging assets out of SB Chain back to the source chain. You only pay source-chain gas via the relayer on exit.

Direction	Protocol Fee	Relayer Fee	SB Chain Gas
Deposit (external → SB Chain)	0.10% of bridged amount	Source-chain gas (ETH, SOL…)	Free
Withdrawal (SB Chain → external)	None	Source-chain gas (ETH, SOL…)	Free

Free withdrawals are deliberate. Charging to exit would contradict the non-custodial architecture — users should never feel penalised for leaving. Revenue is captured on the way in (0.10% deposit fee) and during trading (market fees on every swap). The deposit fee is governance-adjustable per route via bridge_fee_percent; high-volume routes may be reduced to 0.07% once throughput justifies the cut.

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