BeaconVerificationService

Service responsible for cryptographic verification of drand randomness beacons.

This service implements the complete drand beacon verification pipeline, which includes:

1. Round validation - Ensuring the beacon round matches the expected value

2. Randomness validation - Verifying that randomness = SHA256(signature)

3. Signature verification - Cryptographically verifying the BLS signature

The verification process follows the drand specification and ensures that beacons are authentic and have not been tampered with. All beacons must pass all three checks to be considered valid.

Supported Schemes

This service supports all BLS12-381 signing schemes:

• pedersen-bls-chained - League of Entropy default network

• pedersen-bls-unchained - Timelock encryption compatible

• bls-unchained-g1-rfc9380 - Quicknet network (RFC 9380 compliant)

Usage

Typically used internally by DrandClient, but can be used standalone:

val verifier = BeaconVerificationService()
val chainInfo = // ... fetch from drand API
val beacon = // ... fetch beacon

val result = verifier.verifyBeacon(
    chainInfo = chainInfo,
    beacon = beacon,
    expectedRound = 1000
)

result.onSuccess { verifiedBeacon ->
    println("Beacon verified: ${verifiedBeacon.randomness}")
}.onFailure { error ->
    println("Verification failed: ${error.message}")
}

See also