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<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <meta name="generator" content="pdf2htmlEX"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css"> <link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css"> <link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/6251548a6caf5961923ea8ee/raw.css"> <script src="https://static.pudn.com/base/js/compatibility.min.js"></script> <script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script> <script> try{ pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({}); }catch(e){} </script> <title></title> </head> <body> <div id="sidebar" style="display: none"> <div id="outline"> </div> </div> <div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/6251548a6caf5961923ea8ee/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">Hyperledger Fabric: A Distributed Operating System for</div><div class="t m0 x2 h2 y2 ff1 fs0 fc0 sc0 ls0 ws0">Permissioned Blockchains</div><div class="t m0 x3 h3 y3 ff2 fs1 fc0 sc0 ls0 ws0">Elli Androulaki</div><div class="t m0 x4 h3 y4 ff2 fs1 fc0 sc0 ls0 ws0">Artem Barger</div><div class="t m0 x5 h3 y5 ff2 fs1 fc0 sc0 ls0 ws0">Vita Bortnikov</div><div class="t m0 x6 h4 y6 ff2 fs2 fc0 sc0 ls0 ws0">IBM</div><div class="t m0 x7 h3 y3 ff2 fs1 fc0 sc0 ls0 ws0">Christian Cachin</div><div class="t m0 x8 h3 y4 ff2 fs1 fc0 sc0 ls0 ws0">Konstantinos Christidis</div><div class="t m0 x9 h3 y5 ff2 fs1 fc0 sc0 ls0 ws0">Angelo De Caro</div><div class="t m0 xa h3 y7 ff2 fs1 fc0 sc0 ls0 ws0">David Enyeart</div><div class="t m0 xb h4 y8 ff2 fs2 fc0 sc0 ls0 ws0">IBM</div><div class="t m0 xc h3 y3 ff2 fs1 fc0 sc0 ls0 ws0">Christopher Ferris</div><div class="t m0 xd h3 y4 ff2 fs1 fc0 sc0 ls0 ws0">Gennady Laventman</div><div class="t m0 xe h3 y5 ff2 fs1 fc0 sc0 ls0 ws0">Yacov Manevich</div><div class="t m0 xf h4 y6 ff2 fs2 fc0 sc0 ls0 ws0">IBM</div><div class="t m0 x10 h3 y9 ff2 fs1 fc0 sc0 ls0 ws0">Srinivasan Muralidharan</div><div class="t m0 x11 h5 ya ff3 fs3 fc0 sc0 ls0 ws0">∗</div><div class="t m0 x12 h4 yb ff2 fs2 fc0 sc0 ls0 ws0">State Street Corp.</div><div class="t m0 x13 h3 y9 ff2 fs1 fc0 sc0 ls0 ws0">Chet Murthy</div><div class="t m0 x14 h5 ya ff3 fs3 fc0 sc0 ls0 ws0">∗</div><div class="t m0 x15 h3 y9 ff2 fs1 fc0 sc0 ls0 ws0">Binh Nguyen</div><div class="t m0 x16 h5 ya ff3 fs3 fc0 sc0 ls0 ws0">∗</div><div class="t m0 x17 h4 yb ff2 fs2 fc0 sc0 ls0 ws0">State Street Corp.</div><div class="t m0 x18 h3 yc ff2 fs1 fc0 sc0 ls0 ws0">Manish Sethi</div><div class="t m0 x19 h3 yd ff2 fs1 fc0 sc0 ls0 ws0">Gari Singh</div><div class="t m0 x1a h3 ye ff2 fs1 fc0 sc0 ls0 ws0">Keith Smith</div><div class="t m0 x1b h3 yf ff2 fs1 fc0 sc0 ls0 ws0">Alessandro Sorniotti</div><div class="t m0 x1c h4 y10 ff2 fs2 fc0 sc0 ls0 ws0">IBM</div><div class="t m0 x1d h3 yc ff2 fs1 fc0 sc0 ls0 ws0">Chrysoula Stathakopoulou</div><div class="t m0 x1e h3 yd ff2 fs1 fc0 sc0 ls0 ws0">Marko Vukolić</div><div class="t m0 x1f h3 ye ff2 fs1 fc0 sc0 ls0 ws0">Sharon Weed Cocco</div><div class="t m0 x20 h3 yf ff2 fs1 fc0 sc0 ls0 ws0">Jason Yellick</div><div class="t m0 x21 h4 y10 ff2 fs2 fc0 sc0 ls0 ws0">IBM</div><div class="t m0 x22 h6 y11 ff4 fs4 fc0 sc0 ls0 ws0">ABSTRACT</div><div class="t m1 x22 h7 y12 ff2 fs5 fc0 sc0 ls0 ws0">Fabric is a modular and extensible open-source system for deploying</div><div class="t m1 x22 h7 y13 ff2 fs5 fc0 sc0 ls0 ws0">and operating permissioned blockchains and one of the Hyperledger</div><div class="t m0 x22 h7 y14 ff2 fs5 fc0 sc0 ls0 ws0">projects hosted by the Linux Foundation (www.hyperledger.org).</div><div class="t m1 x23 h7 y15 ff2 fs5 fc0 sc0 ls0 ws0">Fabric is the rst truly extensible blockchain system for running</div><div class="t m2 x22 h7 y16 ff2 fs5 fc0 sc0 ls0 ws0">distributed applications. It supports modular consensus protocols,</div><div class="t m3 x22 h7 y17 ff2 fs5 fc0 sc0 ls0 ws0">which allows the system to be tailored to particular use cases and</div><div class="t m4 x22 h7 y18 ff2 fs5 fc0 sc0 ls0 ws0">trust models. Fabric is also the rst blockchain system that runs</div><div class="t m5 x22 h7 y19 ff2 fs5 fc0 sc0 ls0 ws0">distributed applications written in standard, general-purpose pro-</div><div class="t m4 x22 h7 y1a ff2 fs5 fc0 sc0 ls0 ws0">gramming languages, without systemic dependency on a native</div><div class="t m4 x22 h7 y1b ff2 fs5 fc0 sc0 ls0 ws0">cryptocurrency. This stands in sharp contrast to existing block-</div><div class="t m4 x22 h7 y1c ff2 fs5 fc0 sc0 ls0 ws0">chain platforms that require “smart-contracts” to be written in</div><div class="t m6 x22 h7 y1d ff2 fs5 fc0 sc0 ls0 ws0">domain-specic languages or rely on a cryptocurrency. Fabric real-</div><div class="t m1 x22 h7 y1e ff2 fs5 fc0 sc0 ls0 ws0">izes the permissioned model using a portable notion of membership,</div><div class="t m7 x22 h7 y1f ff2 fs5 fc0 sc0 ls0 ws0">which may be integrated with industry-standard identity manage-</div><div class="t m1 x22 h7 y20 ff2 fs5 fc0 sc0 ls0 ws0">ment. To support such exibility, Fabric introduces an entirely novel</div><div class="t m1 x22 h7 y21 ff2 fs5 fc0 sc0 ls0 ws0">blockchain design and revamps the way blockchains cope with non-</div><div class="t m0 x22 h7 y22 ff2 fs5 fc0 sc0 ls0 ws0">determinism, resource exhaustion, and performance attacks.</div><div class="t m4 x23 h7 y23 ff2 fs5 fc0 sc0 ls0 ws0">This paper describes Fabric, its architecture, the rationale be-</div><div class="t m8 x22 h7 y24 ff2 fs5 fc0 sc0 ls0 ws0">hind various design decisions, its most prominent implementation</div><div class="t m2 x22 h7 y25 ff2 fs5 fc0 sc0 ls0 ws0">aspects, as well as its distributed application programming model.</div><div class="t m4 x22 h7 y26 ff2 fs5 fc0 sc0 ls0 ws0">We further evaluate Fabric by implementing and benchmarking</div><div class="t m9 x22 h7 y27 ff2 fs5 fc0 sc0 ls0 ws0">a Bitcoin-inspired digital currency. We show that Fabric achieves</div><div class="t ma x22 h7 y28 ff2 fs5 fc0 sc0 ls0 ws0">end-to-end throughput of more than 3500 transactions per second</div><div class="t m4 x22 h7 y29 ff2 fs5 fc0 sc0 ls0 ws0">in certain popular deployment congurations, with sub-second</div><div class="t m0 x22 h7 y2a ff2 fs5 fc0 sc0 ls0 ws0">latency, scaling well to over 100 peers.</div><div class="t m0 x24 h8 y2b ff3 fs6 fc0 sc0 ls0 ws0">∗</div><div class="t m0 x25 h9 y2c ff2 fs7 fc0 sc0 ls0 ws0">Work done at IBM.</div><div class="t m4 x22 h9 y2d ff2 fs7 fc0 sc0 ls0 ws0">Permission to make digital or hard copies of part or all of this work for personal or</div><div class="t mb x22 h9 y2e ff2 fs7 fc0 sc0 ls0 ws0">classroom use is granted without fee provided that copies are not made or distributed</div><div class="t m1 x22 h9 y2f ff2 fs7 fc0 sc0 ls0 ws0">for prot or commercial advantage and that copies bear this notice and the full citation</div><div class="t m1 x22 h9 y30 ff2 fs7 fc0 sc0 ls0 ws0">on the rst page. Copyrights for third-party components of this work must be honored.</div><div class="t m0 x22 h9 y31 ff2 fs7 fc0 sc0 ls0 ws0">For all other uses, contact the owner/author(s).</div><div class="t m0 x22 ha y32 ff5 fs7 fc0 sc0 ls0 ws0">EuroSys ’18, April 23–26, 2018, Porto, Portugal</div><div class="t m0 x22 h9 y33 ff3 fs7 fc0 sc0 ls0 ws0">© 2018 Copyright held by the owner/author(s).</div><div class="t m0 x22 h9 y34 ff2 fs7 fc0 sc0 ls0 ws0">ACM ISBN 978-1-4503-5584-1/18/04.</div><div class="t m0 x22 h9 y35 ff2 fs7 fc0 sc0 ls0 ws0">https://doi.org/10.1145/3190508.3190538</div><div class="t m0 x26 hb y11 ff4 fs8 fc0 sc0 ls0 ws0">ACM Reference Format:</div><div class="t m1 x26 hc y36 ff2 fs8 fc0 sc0 ls0 ws0">Elli Androulaki, Artem Barger, Vita Bortnikov, Christian Cachin, Konstanti-</div><div class="t m4 x26 hc y37 ff2 fs8 fc0 sc0 ls0 ws0">nos Christidis, Angelo De Caro, David Enyeart, Christopher Ferris, Gen-</div><div class="t mc x26 hc y38 ff2 fs8 fc0 sc0 ls0 ws0">nady Laventman, Yacov Manevich, Srinivasan Muralidharan, Chet Murthy,</div><div class="t md x26 hc y39 ff2 fs8 fc0 sc0 ls0 ws0">Binh Nguyen, Manish Sethi, Gari Singh, Keith Smith, Alessandro Sorniotti,</div><div class="t m4 x26 hc y3a ff2 fs8 fc0 sc0 ls0 ws0">Chrysoula Stathakopoulou, Marko Vukolić, Sharon Weed Cocco, and Ja-</div><div class="t me x26 hc y3b ff2 fs8 fc0 sc0 ls0 ws0">son Yellick. 2018. Hyperledger Fabric: A Distributed Operating System for</div><div class="t mf x26 hc y3c ff2 fs8 fc0 sc0 ls0 ws0">Permissioned Blockchains . In EuroSys ’18: Thirteenth EuroSys Conference</div><div class="t m10 x26 hc y3d ff5 fs8 fc0 sc0 ls0 ws0">2018, April 23–26, 2018, Porto, Portugal. ACM, New York, NY, USA, 15 pages.</div><div class="t m0 x26 hc y3e ff2 fs8 fc0 sc0 ls0 ws0">https://doi.org/10.1145/3190508.3190538</div><div class="t m0 x26 h6 y3f ff4 fs4 fc0 sc0 ls0 ws0">1 INTRODUCTION</div><div class="t m0 x26 h7 y40 ff2 fs5 fc0 sc0 ls0 ws0">A blockchain can be dened as an immutable ledger for recording</div><div class="t m11 x26 h7 y41 ff5 fs5 fc0 sc0 ls0 ws0">transactions, maintained within a distributed network of mutually</div><div class="t m4 x26 h7 y42 ff2 fs5 fc0 sc0 ls0 ws0">untrusting peers. Every peer maintains a copy of the ledger. The</div><div class="t m12 x26 h7 y43 ff2 fs5 fc0 sc0 ls0 ws0">peers execute a consensus protocol to validate transactions, group</div><div class="t m4 x26 h7 y44 ff2 fs5 fc0 sc0 ls0 ws0">them into blocks, and build a hash chain over the blocks. This</div><div class="t m13 x26 h7 y45 ff2 fs5 fc0 sc0 ls0 ws0">process forms the ledger by ordering the transactions, as is neces-</div><div class="t m4 x26 h7 y46 ff2 fs5 fc0 sc0 ls0 ws0">sary for consistency. Blockchains have emerged with Bitcoin [</div><div class="t m0 x27 h7 y46 ff2 fs5 fc0 sc0 ls0 ws0">3</div><div class="t m4 x28 h7 y46 ff2 fs5 fc0 sc0 ls0 ws0">]</div><div class="t m0 x26 h7 y47 ff2 fs5 fc0 sc0 ls0 ws0">and are widely regarded as a promising technology to run trusted</div><div class="t m0 x26 h7 y48 ff2 fs5 fc0 sc0 ls0 ws0">exchanges in the digital world.</div><div class="t m14 x29 h7 y49 ff2 fs5 fc0 sc0 ls0 ws0">In a public or permissionless blockchain anyone can participate</div><div class="t m15 x26 h7 y4a ff2 fs5 fc0 sc0 ls0 ws0">without a specic identity. Public blockchains typically involve a</div><div class="t md x26 h7 y4b ff2 fs5 fc0 sc0 ls0 ws0">native cryptocurrency and often use consensus based on “proof of</div><div class="t m12 x26 h7 y4c ff2 fs5 fc0 sc0 ls0 ws0">work” (PoW) and economic incentives. Permissioned blockchains,</div><div class="t m16 x26 h7 y4d ff2 fs5 fc0 sc0 ls0 ws0">on the other hand, run a blockchain among a set of known, iden-</div><div class="t m4 x26 h7 y4e ff2 fs5 fc0 sc0 ls0 ws0">tied participants. A permissioned blockchain provides a way to</div><div class="t ma x26 h7 y4f ff2 fs5 fc0 sc0 ls0 ws0">secure the interactions among a group of entities that have a com-</div><div class="t m1 x26 h7 y50 ff2 fs5 fc0 sc0 ls0 ws0">mon goal but which do not fully trust each other, such as businesses</div><div class="t m1 x26 h7 y51 ff2 fs5 fc0 sc0 ls0 ws0">that exchange funds, goods, or information. By relying on the iden-</div><div class="t m4 x26 h7 y52 ff2 fs5 fc0 sc0 ls0 ws0">tities of the peers, a permissioned blockchain can use traditional</div><div class="t m0 x26 h7 y53 ff2 fs5 fc0 sc0 ls0 ws0">Byzantine-fault tolerant (BFT) consensus.</div><div class="t m17 x29 h7 y54 ff2 fs5 fc0 sc0 ls0 ws0">Blockchains may execute arbitrary, programmable transaction</div><div class="t m1 x26 h7 y55 ff2 fs5 fc0 sc0 ls0 ws0">logic in the form of smart contracts, as exemplied by Ethereum [</div><div class="t m0 x27 h7 y55 ff2 fs5 fc0 sc0 ls0 ws0">5</div><div class="t m1 x28 h7 y55 ff2 fs5 fc0 sc0 ls0 ws0">].</div><div class="t m18 x26 h7 y56 ff2 fs5 fc0 sc0 ls0 ws0">The scripts in Bitcoin were a predecessor of the concept. A smart</div><div class="t m4 x26 h7 y57 ff2 fs5 fc0 sc0 ls0 ws0">contract functions as a trusted distributed application and gains</div><div class="t m4 x26 h7 y58 ff2 fs5 fc0 sc0 ls0 ws0">its security from the blockchain and the underlying consensus</div><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div> </body> </html>

<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/6251548a6caf5961923ea8ee/bg2.jpg"><div class="t m0 x22 hd y59 ff6 fs5 fc0 sc0 ls0 ws0">EuroSys ’18, April 23–26, 2018, Porto, Portugal E. Androulaki et al.</div><div class="t m1a x22 h7 y5a ff2 fs5 fc0 sc0 ls0 ws0">among the peers. This closely resembles the well-known approach</div><div class="t m4 x22 h7 y5b ff2 fs5 fc0 sc0 ls0 ws0">of building resilient applications with state-machine replication</div><div class="t m1 x22 h7 y5c ff2 fs5 fc0 sc0 ls0 ws0">(SMR) [</div><div class="t m0 x2a h7 y5c ff2 fs5 fc0 sc0 ls0 ws0">48</div><div class="t m1 x2b h7 y5c ff2 fs5 fc0 sc0 ls0 ws0">]. However, blockchains depart from traditional SMR with</div><div class="t m4 x22 h7 y5d ff2 fs5 fc0 sc0 ls0 ws0">Byzantine faults in important ways: (1) not only one, but many</div><div class="t me x22 h7 y5e ff2 fs5 fc0 sc0 ls0 ws0">distributed applications run concurrently; (2) applications may be</div><div class="t m1 x22 h7 y5f ff2 fs5 fc0 sc0 ls0 ws0">deployed dynamically and by anyone; and (3) the application code is</div><div class="t m1 x22 h7 y60 ff2 fs5 fc0 sc0 ls0 ws0">untrusted, potentially even malicious. These dierences necessitate</div><div class="t m0 x22 h7 y61 ff2 fs5 fc0 sc0 ls0 ws0">new designs.</div><div class="t m5 x23 h7 y62 ff2 fs5 fc0 sc0 ls0 ws0">Many existing smart-contract blockchains follow the blueprint</div><div class="t m1b x22 h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">of SMR [</div><div class="t m0 x2c h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">48</div><div class="t m1b x2d h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">] and implement so-called active replication [</div><div class="t m0 x2e h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">27</div><div class="t m1b x9 h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">]: a pro-</div><div class="t m1c x22 h7 y64 ff2 fs5 fc0 sc0 ls0 ws0">tocol for consensus or atomic broadcast rst orders the transactions</div><div class="t m17 x22 h7 y65 ff2 fs5 fc0 sc0 ls0 ws0">and propagates them to all peers; and second, each peer executes</div><div class="t m9 x22 h7 y66 ff2 fs5 fc0 sc0 ls0 ws0">the transactions sequentially. We call this the order-execute archi-</div><div class="t m4 x22 h7 y67 ff5 fs5 fc0 sc0 ls0 ws0">tecture; it requires all peers to execute every transaction and all</div><div class="t m1 x22 h7 y68 ff2 fs5 fc0 sc0 ls0 ws0">transactions to be deterministic. The order-execute architecture can</div><div class="t mb x22 h7 y69 ff2 fs5 fc0 sc0 ls0 ws0">be found in virtually all existing blockchain systems, ranging from</div><div class="t m1d x22 h7 y6a ff2 fs5 fc0 sc0 ls0 ws0">public ones such as Ethereum (with PoW-based consensus) to per-</div><div class="t m1 x22 h7 y6b ff2 fs5 fc0 sc0 ls0 ws0">missioned ones (with BFT-type consensus) such as Tendermint [</div><div class="t m0 x2f h7 y6b ff2 fs5 fc0 sc0 ls0 ws0">14</div><div class="t m1 x30 h7 y6b ff2 fs5 fc0 sc0 ls0 ws0">],</div><div class="t m11 x22 h7 y6c ff2 fs5 fc0 sc0 ls0 ws0">Chain [</div><div class="t m0 x31 h7 y6c ff2 fs5 fc0 sc0 ls0 ws0">4</div><div class="t m11 x2c h7 y6c ff2 fs5 fc0 sc0 ls0 ws0">] and Quorum [</div><div class="t m0 x32 h7 y6c ff2 fs5 fc0 sc0 ls0 ws0">13</div><div class="t m11 x33 h7 y6c ff2 fs5 fc0 sc0 ls0 ws0">]. Although the order-execute design is</div><div class="t m4 x22 h7 y6d ff2 fs5 fc0 sc0 ls0 ws0">not immediately apparent in all systems, because the additional</div><div class="t m1e x22 h7 y6e ff2 fs5 fc0 sc0 ls0 ws0">transaction validation step may blur it, its limitations are inherent</div><div class="t m1c x22 h7 y6f ff2 fs5 fc0 sc0 ls0 ws0">in all: every peer executes every transaction and transactions must</div><div class="t m0 x22 h7 y70 ff2 fs5 fc0 sc0 ls0 ws0">be deterministic.</div><div class="t m4 x23 h7 y71 ff2 fs5 fc0 sc0 ls0 ws0">Prior permissioned blockchains suer from many limitations,</div><div class="t m10 x22 h7 y72 ff2 fs5 fc0 sc0 ls0 ws0">which often stem from their permissionless relatives or from using</div><div class="t m0 x22 h7 y73 ff2 fs5 fc0 sc0 ls0 ws0">the order-execute architecture. In particular:</div><div class="t m0 x25 he y74 ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m4 x34 h7 y74 ff2 fs5 fc0 sc0 ls0 ws0">Consensus is hard-coded within the platform, which con-</div><div class="t me x34 h7 y75 ff2 fs5 fc0 sc0 ls0 ws0">tradicts the well-established understanding that there is no</div><div class="t m0 x35 h7 y76 ff2 fs5 fc0 sc0 ls0 ws0">“one-size-ts-all” (BFT) consensus protocol [52];</div><div class="t m0 x25 he y77 ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m16 x34 h7 y77 ff2 fs5 fc0 sc0 ls0 ws0">The trust model of transaction validation is determined by</div><div class="t m1 x34 h7 y78 ff2 fs5 fc0 sc0 ls0 ws0">the consensus protocol and cannot be adapted to the require-</div><div class="t m0 x34 h7 y79 ff2 fs5 fc0 sc0 ls0 ws0">ments of the smart contract;</div><div class="t m0 x25 he y7a ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m1f x34 h7 y7a ff2 fs5 fc0 sc0 ls0 ws0">Smart contracts must be written in a xed, non-standard, or</div><div class="t me x34 h7 y7b ff5 fs5 fc0 sc0 ls0 ws0">domain-specic language, which hinders wide-spread adop-</div><div class="t m0 x34 h7 y7c ff2 fs5 fc0 sc0 ls0 ws0">tion and may lead to programming errors;</div><div class="t m0 x25 he y7d ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m1 x34 h7 y7d ff2 fs5 fc0 sc0 ls0 ws0">The sequential execution of all transactions by all peers limits</div><div class="t m9 x34 h7 y7e ff5 fs5 fc0 sc0 ls0 ws0">performance, and complex measures are needed to prevent</div><div class="t m4 x34 h7 y7f ff2 fs5 fc0 sc0 ls0 ws0">denial-of-service attacks against the platform originating</div><div class="t m4 x34 h7 y80 ff2 fs5 fc0 sc0 ls0 ws0">from untrusted contracts (such as accounting for runtime</div><div class="t m0 x34 h7 y81 ff2 fs5 fc0 sc0 ls0 ws0">with “gas” in Ethereum);</div><div class="t m0 x25 he y82 ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m6 x34 h7 y82 ff2 fs5 fc0 sc0 ls0 ws0">Transactions must be deterministic, which can be dicult to</div><div class="t m0 x34 h7 y83 ff2 fs5 fc0 sc0 ls0 ws0">ensure programmatically;</div><div class="t m0 x25 he y84 ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m1 x34 h7 y84 ff2 fs5 fc0 sc0 ls0 ws0">Every smart contract runs on all peers, which is at odds with</div><div class="t m17 x34 h7 y85 ff5 fs5 fc0 sc0 ls0 ws0">condentiality, and prohibits the dissemination of contract</div><div class="t m0 x34 h7 y86 ff2 fs5 fc0 sc0 ls0 ws0">code and state to a subset of peers.</div><div class="t m4 x23 h7 y87 ff2 fs5 fc0 sc0 ls0 ws0">In this paper we describe Hyperledger Fabric or simply Fabric,</div><div class="t mc x22 h7 y88 ff2 fs5 fc0 sc0 ls0 ws0">an open-source [</div><div class="t m0 x36 h7 y88 ff2 fs5 fc0 sc0 ls0 ws0">8</div><div class="t mc x37 h7 y88 ff2 fs5 fc0 sc0 ls0 ws0">] blockchain platform that overcomes these limi-</div><div class="t m20 x22 h7 y89 ff2 fs5 fc0 sc0 ls0 ws0">tations. Fabric is one of the projects of Hyperledger [</div><div class="t m0 x8 h7 y89 ff2 fs5 fc0 sc0 ls0 ws0">7</div><div class="t m20 x38 h7 y89 ff2 fs5 fc0 sc0 ls0 ws0">] under the</div><div class="t m8 x22 h7 y8a ff2 fs5 fc0 sc0 ls0 ws0">auspices of the Linux Foundation [</div><div class="t m0 x39 h7 y8a ff2 fs5 fc0 sc0 ls0 ws0">11</div><div class="t m8 x3a h7 y8a ff2 fs5 fc0 sc0 ls0 ws0">]. Fabric is used in more than</div><div class="t m21 x22 h7 y8b ff2 fs5 fc0 sc0 ls0 ws0">400 prototypes, proofs-of-concept, and in production distributed-</div><div class="t m1 x22 h7 y8c ff2 fs5 fc0 sc0 ls0 ws0">ledger systems, across dierent industries and use cases. These use</div><div class="t m4 x22 h7 y8d ff2 fs5 fc0 sc0 ls0 ws0">cases include but are not limited to areas such as dispute resolu-</div><div class="t m1b x22 h7 y8e ff2 fs5 fc0 sc0 ls0 ws0">tion, trade logistics, FX netting, food safety, contract management,</div><div class="t m4 x22 h7 y8f ff2 fs5 fc0 sc0 ls0 ws0">diamond provenance, rewards point management, low liquidity</div><div class="t m1a x22 h7 y90 ff2 fs5 fc0 sc0 ls0 ws0">securities trading and settlement, identity management, and settle-</div><div class="t m0 x22 h7 y91 ff2 fs5 fc0 sc0 ls0 ws0">ment through digital currency.</div><div class="t m4 x29 h7 y5a ff2 fs5 fc0 sc0 ls0 ws0">Fabric introduces a new blockchain architecture aiming at re-</div><div class="t m4 x26 h7 y5b ff2 fs5 fc0 sc0 ls0 ws0">siliency, exibility, scalability, and condentiality. Designed as</div><div class="t m4 x26 h7 y5c ff2 fs5 fc0 sc0 ls0 ws0">a modular and extensible general-purpose permissioned block-</div><div class="t m4 x26 h7 y5d ff2 fs5 fc0 sc0 ls0 ws0">chain, Fabric is the rst blockchain system to support the exe-</div><div class="t m1c x26 h7 y5e ff2 fs5 fc0 sc0 ls0 ws0">cution of distributed applications written in standard programming</div><div class="t m4 x26 h7 y5f ff5 fs5 fc0 sc0 ls0 ws0">languages, in a way that allows them to be executed consistently</div><div class="t m4 x26 h7 y60 ff2 fs5 fc0 sc0 ls0 ws0">across many nodes, giving impression of execution on a single</div><div class="t m4 x26 h7 y61 ff2 fs5 fc0 sc0 ls0 ws0">globally-distributed blockchain computer. This makes Fabric the</div><div class="t m1 x26 h7 y62 ff2 fs5 fc0 sc0 ls0 ws0">rst distributed operating system [</div><div class="t m0 x3b h7 y62 ff2 fs5 fc0 sc0 ls0 ws0">54</div><div class="t m1 x3c h7 y62 ff2 fs5 fc0 sc0 ls0 ws0">] for permissioned blockchains.</div><div class="t mb x29 h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">The architecture of Fabric follows a novel execute-order-validate</div><div class="t m4 x26 h7 y64 ff2 fs5 fc0 sc0 ls0 ws0">paradigm for distributed execution of untrusted code in an un-</div><div class="t m4 x26 h7 y65 ff2 fs5 fc0 sc0 ls0 ws0">trusted environment. It separates the transaction ow into three</div><div class="t m1c x26 h7 y66 ff2 fs5 fc0 sc0 ls0 ws0">steps, which may be run on dierent entities in the system: (1) exe-</div><div class="t m1 x26 h7 y67 ff5 fs5 fc0 sc0 ls0 ws0">cuting a transaction and checking its correctness, thereby endorsing</div><div class="t m22 x26 h7 y68 ff2 fs5 fc0 sc0 ls0 ws0">it (corresponding to “transaction validation” in other blockchains);</div><div class="t m4 x26 h7 y69 ff2 fs5 fc0 sc0 ls0 ws0">(2) ordering through a consensus protocol, irrespective of trans-</div><div class="t m4 x26 h7 y6a ff2 fs5 fc0 sc0 ls0 ws0">action semantics; and (3) transaction validation per application-</div><div class="t m1 x26 h7 y6b ff2 fs5 fc0 sc0 ls0 ws0">specic trust assumptions, which also prevents race conditions due</div><div class="t m0 x26 h7 y6c ff2 fs5 fc0 sc0 ls0 ws0">to concurrency.</div><div class="t m14 x29 h7 y6d ff2 fs5 fc0 sc0 ls0 ws0">This design departs radically from the order-execute paradigm</div><div class="t m4 x26 h7 y6e ff2 fs5 fc0 sc0 ls0 ws0">in that Fabric typically executes transactions before reaching -</div><div class="t m4 x26 h7 y6f ff2 fs5 fc0 sc0 ls0 ws0">nal agreement on their order. It combines the two well-known</div><div class="t m0 x26 h7 y70 ff2 fs5 fc0 sc0 ls0 ws0">approaches to replication, passive and active, as follows.</div><div class="t m23 x29 h7 y71 ff2 fs5 fc0 sc0 ls0 ws0">First, Fabric uses passive or primary-backup replication [</div><div class="t m0 x3d h7 y71 ff2 fs5 fc0 sc0 ls0 ws0">21</div><div class="t m23 x3e h7 y71 ff2 fs5 fc0 sc0 ls0 ws0">,</div><div class="t m0 x3f h7 y71 ff2 fs5 fc0 sc0 ls0 ws0">27</div><div class="t m23 x28 h7 y71 ff2 fs5 fc0 sc0 ls0 ws0">]</div><div class="t m1 x26 h7 y72 ff2 fs5 fc0 sc0 ls0 ws0">as often found in distributed databases, but with middleware-based</div><div class="t m4 x26 h7 y73 ff2 fs5 fc0 sc0 ls0 ws0">asymmetric update processing [</div><div class="t m0 x40 h7 y73 ff2 fs5 fc0 sc0 ls0 ws0">40</div><div class="t m4 x41 h7 y73 ff2 fs5 fc0 sc0 ls0 ws0">,</div><div class="t m0 x42 h7 y73 ff2 fs5 fc0 sc0 ls0 ws0">41</div><div class="t m4 x43 h7 y73 ff2 fs5 fc0 sc0 ls0 ws0">] and ported to untrusted</div><div class="t m10 x26 h7 y92 ff2 fs5 fc0 sc0 ls0 ws0">environments with Byzantine faults. In Fabric, every transaction is</div><div class="t m1 x26 h7 y93 ff2 fs5 fc0 sc0 ls0 ws0">executed (endorsed) only by a subset of the peers, which allows for</div><div class="t m24 x26 h7 y94 ff2 fs5 fc0 sc0 ls0 ws0">parallel execution and addresses potential non-determinism, draw-</div><div class="t m1 x26 h7 y95 ff2 fs5 fc0 sc0 ls0 ws0">ing on “execute-verify” BFT replication [</div><div class="t m0 x43 h7 y95 ff2 fs5 fc0 sc0 ls0 ws0">37</div><div class="t m1 x44 h7 y95 ff2 fs5 fc0 sc0 ls0 ws0">]. A exible endorsement</div><div class="t m8 x26 h7 y96 ff2 fs5 fc0 sc0 ls0 ws0">policy species which peers, or how many of them, need to vouch</div><div class="t m0 x26 h7 y97 ff2 fs5 fc0 sc0 ls0 ws0">for the correct execution of a given smart contract.</div><div class="t mf x29 h7 y98 ff2 fs5 fc0 sc0 ls0 ws0">Second, Fabric incorporates active replication in the sense that</div><div class="t m9 x26 h7 y99 ff2 fs5 fc0 sc0 ls0 ws0">the transaction’s eects on the ledger state are only written after</div><div class="t m1 x26 h7 y9a ff2 fs5 fc0 sc0 ls0 ws0">reaching consensus on a total order among them, in the determinis-</div><div class="t m0 x26 h7 y9b ff2 fs5 fc0 sc0 ls0 ws0">tic validation step executed by each peer individually. This allows</div><div class="t m13 x26 h7 y9c ff2 fs5 fc0 sc0 ls0 ws0">Fabric to respect application-specic trust assumptions according</div><div class="t m4 x26 h7 y9d ff2 fs5 fc0 sc0 ls0 ws0">to the transaction endorsement. Moreover, the ordering of state</div><div class="t m4 x26 h7 y9e ff2 fs5 fc0 sc0 ls0 ws0">updates is delegated to a modular component for consensus (i.e.,</div><div class="t m1f x26 h7 y9f ff2 fs5 fc0 sc0 ls0 ws0">atomic broadcast), which is stateless and logically decoupled from</div><div class="t m0 x26 h7 ya0 ff2 fs5 fc0 sc0 ls0 ws0">the peers that execute transactions and maintain the ledger. Since</div><div class="t m4 x26 h7 ya1 ff2 fs5 fc0 sc0 ls0 ws0">consensus is modular, its implementation can be tailored to the</div><div class="t mb x26 h7 ya2 ff2 fs5 fc0 sc0 ls0 ws0">trust assumption of a particular deployment. Although it is readily</div><div class="t m25 x26 h7 ya3 ff2 fs5 fc0 sc0 ls0 ws0">possible to use the blockchain peers also for implementing consen-</div><div class="t m1d x26 h7 ya4 ff2 fs5 fc0 sc0 ls0 ws0">sus, the separation of the two roles adds exibility and allows one</div><div class="t m1 x26 h7 ya5 ff2 fs5 fc0 sc0 ls0 ws0">to rely on well-established toolkits for CFT (crash fault-tolerant) or</div><div class="t m0 x26 h7 ya6 ff2 fs5 fc0 sc0 ls0 ws0">BFT ordering.</div><div class="t m1e x29 h7 ya7 ff2 fs5 fc0 sc0 ls0 ws0">Overall, this hybrid replication design, which mixes passive and</div><div class="t m4 x26 h7 ya8 ff2 fs5 fc0 sc0 ls0 ws0">active replication in the Byzantine model, and the execute-order-</div><div class="t m9 x26 h7 ya9 ff5 fs5 fc0 sc0 ls0 ws0">validate paradigm, represent the main innovation in Fabric archi-</div><div class="t m6 x26 h7 yaa ff2 fs5 fc0 sc0 ls0 ws0">tecture. They resolve the issues mentioned before and make Fabric</div><div class="t mb x26 h7 yab ff2 fs5 fc0 sc0 ls0 ws0">a scalable system for permissioned blockchains supporting exible</div><div class="t m0 x26 h7 yac ff2 fs5 fc0 sc0 ls0 ws0">trust assumptions.</div><div class="t m1 x29 h7 yad ff2 fs5 fc0 sc0 ls0 ws0">To implement this architecture, Fabric contains modular building</div><div class="t m0 x26 h7 yae ff2 fs5 fc0 sc0 ls0 ws0">blocks for each of the following components:</div><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div>

<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/6251548a6caf5961923ea8ee/bg3.jpg"><div class="t m0 x22 hd y59 ff6 fs5 fc0 sc0 ls0 ws0">Hyperledger Fabric: A Distributed Operating System for Permissioned Blockchains EuroSys ’18, April 23–26, 2018, Porto, Portugal</div><div class="t m0 x25 he y5a ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m4 x34 h7 y5a ff2 fs5 fc0 sc0 ls0 ws0">An ordering service atomically broadcasts state updates to</div><div class="t m1 x34 h7 y5b ff2 fs5 fc0 sc0 ls0 ws0">peers and establishes consensus on the order of transactions.</div><div class="t m0 x25 he y5c ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t mc x34 h7 y5c ff2 fs5 fc0 sc0 ls0 ws0">A membership service provider is responsible for associating</div><div class="t m1c x34 h7 y5d ff2 fs5 fc0 sc0 ls0 ws0">peers with cryptographic identities. It maintains the permis-</div><div class="t m0 x34 h7 y5e ff2 fs5 fc0 sc0 ls0 ws0">sioned nature of Fabric.</div><div class="t m0 x25 he y5f ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m1 x34 h7 y5f ff2 fs5 fc0 sc0 ls0 ws0">An optional p eer-to-peer gossip service disseminates the blocks</div><div class="t m0 x34 h7 y60 ff2 fs5 fc0 sc0 ls0 ws0">output by ordering service to all peers.</div><div class="t m0 x25 he y61 ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m1 x34 h7 y61 ff5 fs5 fc0 sc0 ls0 ws0">Smart contracts in Fabric run within a container environment</div><div class="t m1a x34 h7 y62 ff2 fs5 fc0 sc0 ls0 ws0">for isolation. They can be written in standard programming</div><div class="t m0 x34 h7 y63 ff2 fs5 fc0 sc0 ls0 ws0">languages but do not have direct access to the ledger state.</div><div class="t m0 x25 he y64 ff7 fs5 fc0 sc0 ls0 ws0">•</div><div class="t m4 x34 h7 y64 ff2 fs5 fc0 sc0 ls0 ws0">Each peer locally maintains the ledger in the form of the</div><div class="t m1 x34 h7 y65 ff2 fs5 fc0 sc0 ls0 ws0">append-only blockchain and as a snapshot of the most recent</div><div class="t m0 x34 h7 y66 ff2 fs5 fc0 sc0 ls0 ws0">state in a key-value store.</div><div class="t m24 x23 h7 yaf ff2 fs5 fc0 sc0 ls0 ws0">The remainder of this paper describes the architecture of Fabric</div><div class="t m21 x22 h7 yb0 ff2 fs5 fc0 sc0 ls0 ws0">and our experience with it. Section 2 summarizes the state of the</div><div class="t m6 x22 h7 yb1 ff2 fs5 fc0 sc0 ls0 ws0">art and explains the rationale behind various design decisions. Sec-</div><div class="t m26 x22 h7 yb2 ff2 fs5 fc0 sc0 ls0 ws0">tion 3 introduces the architecture and the execute-order-validate</div><div class="t me x22 h7 yb3 ff2 fs5 fc0 sc0 ls0 ws0">approach of Fabric in detail, illustrating the transaction execution</div><div class="t m1 x22 h7 yb4 ff2 fs5 fc0 sc0 ls0 ws0">ow. In Section 4, the key components of Fabric are dened, in par-</div><div class="t m10 x22 h7 yb5 ff2 fs5 fc0 sc0 ls0 ws0">ticular, the ordering service, membership service, peer-to-peer gos-</div><div class="t m20 x22 h7 yb6 ff2 fs5 fc0 sc0 ls0 ws0">sip, ledger database, and smart-contract API. Results and insights</div><div class="t m1 x22 h7 yb7 ff2 fs5 fc0 sc0 ls0 ws0">gained in a performance evaluation of Fabric with a Bitcoin-inspired</div><div class="t m14 x22 h7 yb8 ff2 fs5 fc0 sc0 ls0 ws0">cryptocurrency, deployed in a cluster and WAN environments on</div><div class="t m1 x22 h7 yb9 ff2 fs5 fc0 sc0 ls0 ws0">commodity public cloud VMs, are given in Section 5. They show that</div><div class="t m1 x22 h7 yba ff2 fs5 fc0 sc0 ls0 ws0">Fabric achieves, in popular deployment congurations, throughput</div><div class="t m6 x22 h7 ybb ff2 fs5 fc0 sc0 ls0 ws0">of more than 3500 tps, achieving nality [</div><div class="t m0 x45 h7 ybb ff2 fs5 fc0 sc0 ls0 ws0">57</div><div class="t m6 x46 h7 ybb ff2 fs5 fc0 sc0 ls0 ws0">] with latency of a few</div><div class="t m4 x22 h7 ybc ff2 fs5 fc0 sc0 ls0 ws0">hundred ms and scaling well to over 100 peers. In Section 6 we</div><div class="t mc x22 h7 ybd ff2 fs5 fc0 sc0 ls0 ws0">discuss a few real production use cases of Fabric. Finally, Section 7</div><div class="t m0 x22 h7 ybe ff2 fs5 fc0 sc0 ls0 ws0">discusses related work.</div><div class="t m0 x22 h6 ybf ff4 fs4 fc0 sc0 ls0 ws0">2 BACKGROUND</div><div class="t m0 x22 h6 yc0 ff4 fs4 fc0 sc0 ls0 ws0">2.1 Order-Execute Architecture for</div><div class="t m0 x34 h6 yc1 ff4 fs4 fc0 sc0 ls0 ws0">Blockchains</div><div class="t m21 x22 h7 yc2 ff2 fs5 fc0 sc0 ls0 ws0">All previous blockchain systems, permissioned or not, follow the</div><div class="t m4 x22 h7 yc3 ff2 fs5 fc0 sc0 ls0 ws0">order-execute architecture. This means that the blockchain net-</div><div class="t m1 x22 h7 yc4 ff2 fs5 fc0 sc0 ls0 ws0">work orders transactions rst, using a consensus protocol, and then</div><div class="t m0 x22 h7 yc5 ff2 fs5 fc0 sc0 ls0 ws0">executes them in the same order on all peers sequentially.</div><div class="t m0 x7 hf yc6 ff2 fs9 fc0 sc0 ls0 ws0">1</div><div class="t m4 x23 h7 yc7 ff2 fs5 fc0 sc0 ls0 ws0">For instance, a PoW-based permissionless blockchain such as</div><div class="t m4 x22 h7 yc8 ff2 fs5 fc0 sc0 ls0 ws0">Ethereum combines consensus and execution of transactions as</div><div class="t m1 x22 h7 yc9 ff2 fs5 fc0 sc0 ls0 ws0">follows: (1) every peer (i.e., a node that participates in consensus) as-</div><div class="t mc x22 h7 yca ff2 fs5 fc0 sc0 ls0 ws0">sembles a block containing valid transactions (to establish validity,</div><div class="t m1 x22 h7 ycb ff2 fs5 fc0 sc0 ls0 ws0">this peer already pre-executes those transactions); (2) the peer tries</div><div class="t m4 x22 h7 ycc ff2 fs5 fc0 sc0 ls0 ws0">to solve a PoW puzzle [</div><div class="t m0 x47 h7 ycc ff2 fs5 fc0 sc0 ls0 ws0">44</div><div class="t m4 x48 h7 ycc ff2 fs5 fc0 sc0 ls0 ws0">]; (3) if the peer is lucky and solves the</div><div class="t mc x22 h7 ycd ff2 fs5 fc0 sc0 ls0 ws0">puzzle, it disseminates the block to the network via a gossip proto-</div><div class="t m25 x22 h7 yce ff2 fs5 fc0 sc0 ls0 ws0">col; and (4) every peer receiving the block validates the solution to</div><div class="t m8 x22 h7 ycf ff2 fs5 fc0 sc0 ls0 ws0">the puzzle and all transactions in the block. Eectively, every peer</div><div class="t m23 x22 h7 yd0 ff2 fs5 fc0 sc0 ls0 ws0">thereby repeats the execution of the lucky peer from its rst step.</div><div class="t m4 x22 h7 yd1 ff2 fs5 fc0 sc0 ls0 ws0">Moreover, all peers execute the transactions se quentially (within</div><div class="t m4 x22 h7 yd2 ff2 fs5 fc0 sc0 ls0 ws0">one block and across blocks). The order-execute architecture is</div><div class="t m0 x22 h7 yd3 ff2 fs5 fc0 sc0 ls0 ws0">illustrated by Fig. 1.</div><div class="t m1 x23 h7 yd4 ff2 fs5 fc0 sc0 ls0 ws0">Existing permissioned blockchains such as Tendermint, Chain, or</div><div class="t m1 x22 h7 yd5 ff2 fs5 fc0 sc0 ls0 ws0">Quorum typically use BFT consensus [</div><div class="t m0 x49 h7 yd5 ff2 fs5 fc0 sc0 ls0 ws0">24</div><div class="t m1 x19 h7 yd5 ff2 fs5 fc0 sc0 ls0 ws0">], provided by PBFT [</div><div class="t m0 x4a h7 yd5 ff2 fs5 fc0 sc0 ls0 ws0">26</div><div class="t m1 x2f h7 yd5 ff2 fs5 fc0 sc0 ls0 ws0">] or</div><div class="t m7 x22 h7 yd6 ff2 fs5 fc0 sc0 ls0 ws0">other protocols for atomic broadcast. Nevertheless, they all follow</div><div class="t m0 x4b h8 yd7 ff2 fs6 fc0 sc0 ls0 ws0">1</div><div class="t m4 x25 h9 yd8 ff2 fs7 fc0 sc0 ls0 ws0">In many blockchains with a hard-coded primary application, such as Bitcoin,</div><div class="t m4 x22 h9 yd9 ff2 fs7 fc0 sc0 ls0 ws0">this transaction execution is called “transaction validation.” Here we call this step</div><div class="t m0 x22 h9 yda ff5 fs7 fc0 sc0 ls0 ws0">transaction execution to harmonize the terminology.</div><div class="c x4c ydb w2 h10"><div class="t m0 x6 h11 ydc ff8 fsa fc0 sc0 ls0 ws0">Update stateOrder Execute</div><div class="t m0 x4b h12 ydd ff9 fsb fc0 sc0 ls0 ws0">●</div><div class="t m0 x4d h13 yde ff8 fsc fc0 sc0 ls0 ws0">Deterministic (!)</div><div class="t m0 x4d h13 ydf ff8 fsc fc0 sc0 ls0 ws0">execution</div><div class="t m0 x4e h12 ydd ff9 fsb fc0 sc0 ls0 ws0">●</div><div class="t m0 x4f h13 yde ff8 fsc fc0 sc0 ls0 ws0">Persist state on </div><div class="t m0 x4f h13 ydf ff8 fsc fc0 sc0 ls0 ws0">all peers</div><div class="t m0 x50 h12 ydd ff9 fsb fc0 sc0 ls0 ws0">●</div><div class="t m0 x51 h13 yde ff8 fsc fc0 sc0 ls0 ws0">Consensus or </div><div class="t m0 x51 h13 ydf ff8 fsc fc0 sc0 ls0 ws0">atomic broadcast</div></div><div class="t m0 x52 h14 ye0 ff4 fs5 fc0 sc0 ls0 ws0">Figure 1: Order-execute architecture in replicated services.</div><div class="t m4 x26 h7 ye1 ff2 fs5 fc0 sc0 ls0 ws0">the same order-execute approach and implement classical active</div><div class="t m0 x26 h7 ye2 ff2 fs5 fc0 sc0 ls0 ws0">SMR [27, 48].</div><div class="t m0 x26 h6 ye3 ff4 fs4 fc0 sc0 ls0 ws0">2.2 Limitations of Order-Execute</div><div class="t m1 x26 h7 ye4 ff2 fs5 fc0 sc0 ls0 ws0">The order-execute architecture is conceptually simple and therefore</div><div class="t m1b x26 h7 ye5 ff2 fs5 fc0 sc0 ls0 ws0">also widely used. However, it has several drawbacks when used in</div><div class="t m27 x26 h7 ye6 ff2 fs5 fc0 sc0 ls0 ws0">a general-purpose permissioned blockchain. We discuss the three</div><div class="t m0 x26 h7 ye7 ff2 fs5 fc0 sc0 ls0 ws0">most signicant ones next.</div><div class="t m10 x29 h7 ye8 ff5 fs5 fc0 sc0 ls0 ws0">Sequential execution. Executing the transactions sequentially on</div><div class="t m4 x26 h7 ye9 ff2 fs5 fc0 sc0 ls0 ws0">all peers limits the eective throughput that can be achieved by</div><div class="t m6 x26 h7 yea ff2 fs5 fc0 sc0 ls0 ws0">the blockchain. In particular, since the throughput is inversely pro-</div><div class="t m1 x26 h7 yeb ff2 fs5 fc0 sc0 ls0 ws0">portional to the execution latency, this may become a performance</div><div class="t m1 x26 h7 yec ff2 fs5 fc0 sc0 ls0 ws0">bottleneck for all but the simplest smart contracts. Moreover, recall</div><div class="t m1 x26 h7 yed ff2 fs5 fc0 sc0 ls0 ws0">that in contrast to traditional SMR, the blockchain forms a universal</div><div class="t m7 x26 h7 yee ff2 fs5 fc0 sc0 ls0 ws0">computing engine and its payload applications might be deployed</div><div class="t m23 x26 h7 yef ff2 fs5 fc0 sc0 ls0 ws0">by an adversary. A denial-of-service (DoS) attack, which severely</div><div class="t m4 x26 h7 yf0 ff2 fs5 fc0 sc0 ls0 ws0">reduces the performance of such a blockchain, could simply in-</div><div class="t m3 x26 h7 yf1 ff2 fs5 fc0 sc0 ls0 ws0">troduce smart contracts that take a very long time to execute. For</div><div class="t m22 x26 h7 yf2 ff2 fs5 fc0 sc0 ls0 ws0">example, a smart contract that executes an innite loop has a fatal</div><div class="t m4 x26 h7 yf3 ff2 fs5 fc0 sc0 ls0 ws0">eect, but cannot be detected automatically because the halting</div><div class="t m0 x26 h7 yf4 ff2 fs5 fc0 sc0 ls0 ws0">problem is unsolvable.</div><div class="t m1 x29 h7 yf5 ff2 fs5 fc0 sc0 ls0 ws0">To cope with this issue, public programmable blockchains with a</div><div class="t m1d x26 h7 yf6 ff2 fs5 fc0 sc0 ls0 ws0">cryptocurrency account for the execution cost. Ethereum [</div><div class="t m0 x53 h7 yf6 ff2 fs5 fc0 sc0 ls0 ws0">58</div><div class="t m1d x54 h7 yf6 ff2 fs5 fc0 sc0 ls0 ws0">], for</div><div class="t m8 x26 h7 yf7 ff2 fs5 fc0 sc0 ls0 ws0">example, introduces the concept of gas consumed by a transaction</div><div class="t m4 x26 h7 yf8 ff2 fs5 fc0 sc0 ls0 ws0">execution, which is converted at a gas price to a cost in the cryp-</div><div class="t m1 x26 h7 yf9 ff2 fs5 fc0 sc0 ls0 ws0">tocurrency and billed to the submitter of the transaction. Ethereum</div><div class="t m4 x26 h7 yfa ff2 fs5 fc0 sc0 ls0 ws0">goes a long way to support this concept, assigns a cost to every</div><div class="t m1 x26 h7 yfb ff2 fs5 fc0 sc0 ls0 ws0">low-level computation step, introducing its own VM for controlling</div><div class="t m1e x26 h7 yfc ff2 fs5 fc0 sc0 ls0 ws0">execution. Although this appears to be a viable solution for public</div><div class="t m4 x26 h7 yfd ff2 fs5 fc0 sc0 ls0 ws0">blockchains, it is not adequate in the permissioned model for a</div><div class="t m0 x26 h7 yfe ff2 fs5 fc0 sc0 ls0 ws0">general-purpose system without a native cryptocurrency.</div><div class="t m16 x29 h7 yff ff2 fs5 fc0 sc0 ls0 ws0">The distributed-systems literature proposes many ways to im-</div><div class="t m22 x26 h7 y100 ff2 fs5 fc0 sc0 ls0 ws0">prove performance compared to sequential execution, for instance</div><div class="t m16 x26 h7 y101 ff2 fs5 fc0 sc0 ls0 ws0">through parallel execution of unrelated operations [</div><div class="t m0 x55 h7 y101 ff2 fs5 fc0 sc0 ls0 ws0">46</div><div class="t m16 x56 h7 y101 ff2 fs5 fc0 sc0 ls0 ws0">]. Unfortu-</div><div class="t m4 x26 h7 y102 ff2 fs5 fc0 sc0 ls0 ws0">nately, such techniques are still to be applied successfully in the</div><div class="t m1e x26 h7 y103 ff2 fs5 fc0 sc0 ls0 ws0">blockchain context of smart contracts. For instance, one challenge</div><div class="t m1f x26 h7 y104 ff2 fs5 fc0 sc0 ls0 ws0">is the requirement for deterministically inferring all dependencies</div><div class="t m1 x26 h7 y105 ff2 fs5 fc0 sc0 ls0 ws0">across smart contracts, which is particularly challenging when com-</div><div class="t m1a x26 h7 y106 ff2 fs5 fc0 sc0 ls0 ws0">bined with possible condentiality constraints. Furthermore, these</div><div class="t m1 x26 h7 y107 ff2 fs5 fc0 sc0 ls0 ws0">techniques are of no help against DoS attacks by contract code from</div><div class="t m0 x26 h7 y108 ff2 fs5 fc0 sc0 ls0 ws0">untrusted developers.</div><div class="t m1 x29 h7 y109 ff5 fs5 fc0 sc0 ls0 ws0">Non-deterministic code. Another important problem for an order-</div><div class="t m1 x26 h7 y10a ff2 fs5 fc0 sc0 ls0 ws0">execute architecture are non-deterministic transactions. Operations</div><div class="t m9 x26 h7 y10b ff2 fs5 fc0 sc0 ls0 ws0">executed after consensus in active SMR must be deterministic, or</div><div class="t m4 x26 h7 y10c ff2 fs5 fc0 sc0 ls0 ws0">the distributed ledger “forks” and violates the basic premise of a</div><div class="t m4 x26 h7 y10d ff2 fs5 fc0 sc0 ls0 ws0">blockchain, that all peers hold the same state. This is usually ad-</div><div class="t m1 x26 h7 y10e ff2 fs5 fc0 sc0 ls0 ws0">dressed by programming blockchains in domain-specic languages</div><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m19"></div></a></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div>