Bridge uses same key custody for >30% validators
A cross-chain & bridge factor in the v1.7.0 rubric. Measured per protocol on a s cadence.
Methodology how we score #
**What this measures** This factor checks whether more than 30% of bridge validators share a single key custodian — defined as a single cloud key management service, hardware vendor, or institutional custody provider holding keys on behalf of multiple validators. OSINT and bridge documentation are the primary assessment methods. This factor applies only to bridge-touching protocols; non-bridge protocols show this factor as N/A.
**Why it matters** Custodian concentration means that a single compromise event — a cloud KMS breach, a hardware wallet vendor supply-chain attack, or an institutional custody failure — can simultaneously compromise multiple validator keys. This converts a k-of-M multisig into a 1-of-1 institutional-custodian attack surface in the worst case. The T-01 evidence base links shared-custodian patterns to approximately 2 protocols in the hack database. Harmony Bridge's signer-set compromise was facilitated in part by operational proximity among the five signers, reducing the effective independence of each key.
**Green / Yellow / Red** Green is scored when no single custodian holds keys for more than 20% of the validator set and custody diversity is documented. Yellow is scored when a single custodian controls 20–30% of the validator set or when custody information is partially undocumented. Red is scored when a single custodian controls more than 30% of the validator set, or when a quorum of validators share a single custodian.
**Common gray cases** Gray is applied when custody arrangements cannot be determined from public documentation and OSINT cannot confidently identify custodian relationships.
**Notable historical examples** No cross-hacked incidents are currently linked in the database for this factor.
Measurement what to look for #
Determine whether >30% of bridge validators share a single key custodian.