Bandwidth Analysis: From 6.3 Gbps to 237 Mbps

Post-quantum signatures are big. ML-DSA-65 runs 3,293 bytes per signature, roughly 51x larger than Ed25519. At 30,000 TPS, naively gossiping every signature would need about 6.3 Gbps per validator. No commodity hardware can handle that.

QBit uses ZK-STARK proof aggregation instead. Sentries batch transactions and produce a single STARK proof per batch. That proof is approximately 147 KB and covers all signatures in the batch.

The numbers for a batch of 1,000 transactions: - Raw signature bandwidth: 1,000 x 3,293 bytes = ~3.3 MB per batch - STARK proof size: ~147 KB per batch - Compression ratio: ~22x per batch

Validators only receive each proof once via the DAG, eliminating redundant gossip. Total bandwidth lands at approximately 237 Mbps. A standard 500 Mbps fiber connection handles that easily.

That's the core tradeoff: move the expensive work (signature verification) off-chain to specialized hardware, and only propagate the proof that the work was done correctly.