Bridge Security Budget Calculator

Cross-chain bridges are a favorite attack target precisely because they concentrate huge value behind a relatively small set of signers, and this calculator sizes the security spend and attack economics around that reality. Annual security budget is simply your Total Value Locked times a security-spend percentage you set (industry practice generally runs 0.1–2% of TVL), which then divides evenly across your validator/guardian count to get an annual cost per validator. The headline "estimated attack cost" figure is the calculator's core insight: it assumes an attacker only needs to corrupt enough validators to reach your signature threshold (the M in an M-of-N multisig), so it multiplies cost-per-validator by that threshold number as a rough proxy for what buying off (or otherwise compromising) the minimum viable set of signers would cost.

A lower signature threshold relative to validator count is cheaper to attack even if the total validator set is large — this is captured separately in the Byzantine Fault Tolerance percentage, computed as (threshold − 1) divided by validator count, representing the share of validators that can be dishonest before the system breaks. The TVL/security ratio flags a different risk dimension: how many dollars of value sit behind each dollar of annual security spend, with anything above roughly 500x flagged as thin protection for the assets at stake. Keep in mind the attack-cost figure is a simplified economic proxy, not a real threat model — it doesn't account for validator collusion resistance, slashing, or reputational costs that make bribing validators harder than the raw dollar math implies.