Digital signatures make blocks and votes transferable evidence: one party can prove to another what a third party said. Authenticated channels convince only the direct receiver, so a proposer that references another party's block cannot prove to the voters who published it. High-throughput signature-free protocols therefore complete an availability vote or a reliable broadcast for every published data block before a proposer may reference it. We present Vantage, a partially synchronous Byzantine fault-tolerant protocol for $n \ge 3f+1$ parties, at most $f$ Byzantine, that uses only authenticated channels and collision-resistant hashing. Parties publish blocks on hash-linked author lanes; each view's proposer pairs a core manifest of lane prefixes that a quorum has acknowledged to it with an optimistic tip manifest of blocks it has just received. A new primitive, Availability-Graded Broadcast (AGB), makes the core irrevocable on a quorum of directly received acknowledgments while grading, rather than blocking on, the tip. A view that AGB leaves open or silent is decided by an on-demand instance of information-theoretic agreement. A block may thus be referenced in a proposal one message delay after publication, as in signed optimistic designs. Let $δ$ be the message delay after global stabilization (GST). With all parties correct, a proposal commits within $2δ$ of its send if all $n$ parties support it, and within $3δ$ on the quorum path, so a block published in time for the next proposal is sequenced $3δ$ to $4δ$ after publication. Safety holds under asynchrony; liveness holds after GST. On an emulated ten-region WAN with 100 parties, Vantage has the lowest p50 latency among compared signed and signature-free protocols at every offered load up to its peak, and sequences 250k 512-byte transactions per second at median end-to-end latency below 500 ms.

翻译：暂无翻译