Invalidity dossier
US 7797457
Leaderless byzantine consensus
Current assignee: Microsoft Technology Licensing LLC
Added 9/23/2026, 7:10:49 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
US7797457B2 — "Leaderless byzantine consensus"
Bibliographic data (from source): Inventor Leslie Lamport. Original assignee [Microsoft Corp.](/litigations/by-plaintiff/Microsoft%20Corp.); current assignee listed as Microsoft Technology Licensing LLC. Application US11/373,483, filed 2006-03-10; priority date 2006-03-10; published as US20070214355A1 on 2007-09-13; granted 2010-09-14. Status listed as Active, with adjusted expiration 2029-05-22 (legal status is an assumption per the source). Classifications include G06F11/14, G06F11/1425, G06F11/182, G06F11/187 and H04L63/14.
Purpose: The invention replaces the leader server that proposes commands for servers executing an asynchronous consensus algorithm, such as Paxos, with a "synchronous virtual leader algorithm" executed by each server. The synchronous agreement algorithm determining the virtual leader's actions is called the leader agreement algorithm. The asynchronous consensus algorithm performed by the virtual leader and servers may be Paxos, but "any asynchronous Byzantine agreement algorithm may be used." Motivation: synchronous consensus algorithms are unsuitable for normally synchronous systems because loss of synchrony can cause inconsistency, while asynchronous algorithms maintain consistency despite arbitrary delays, though progress requires finite message delay.
Plain-language scope: Rather than electing one physical leader, each server runs a synchronous algorithm that agrees on what a "virtual leader" would propose; that proposal then feeds the asynchronous consensus protocol. The source describes a system with servers 101–103 and clients 121–122 (no limit on numbers), Paxos's two-phase numbered proposals, and a method (FIG. 3) for selecting the message the virtual leader proposes for a particular Paxos phase 2. Other named algorithms: Fast Paxos, Generalized Paxos, Byzantine Paxos, Fast Byzantine Paxos, Castro-Liskov.
Not established by the excerpt: The full text of any claim, the precise claim scope, whether all described embodiments are claimed, and the contents of omitted passages. This summary relies solely on the supplied excerpt.
Source: https://patents.google.com/patent/[US7797457](/patent/US7797457)/en
Generated 10/1/2026, 9:42:17 PM
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