Sosp19 Solar Daytime 1, Blockchain Session
The minute session on Day 1 was on blockchains. There were iii papers on this session.
Bitcoin's throughput is a measly iv transactions per minute equally express past times Nakamoto consensus. This leads to hand off-chain scaling via payment networks, e.g. To found a multihop connectedness these pairwise connections are utilized equally intermediaries. There are iii phases to a payment network: setup a multihop connection, procedure payments for closed to time, perform a short town where the concluding remainder is written dorsum to the blockchain.
To guard against a roll-back assault together with ensure that the right remainder is written, the blockchain is used equally the origin of trust. If a node misbehaves, writes an wrong amount, the other reacts inside delta time, corrects past times providing proof of lightning transactions, resolves the situation, and gets incentive for it.
The work amongst this is that the reaction fourth dimension delta requires synchronous access. Spam/congestion attacks tin brand closed to transactions bring to a greater extent than than vii days to locomote written to the chain. So what should locomote the appropriate value of delta, the reaction time? Security of the payment channel should non rely on read/write latencies.
To address this issue, the newspaper proposes Teechain, the kickoff asynchronous blockchain access payment network. Teechain removes the blockchain equally root-of trust past times introducing closed to other origin of trust, a treasury. Treasury controls funds, balances, together with payments. But how produce nosotros realize treasuries for blockchains, avoiding centralization together with trust?
Teechain uses committees for realizing treasuries for blockchains. A treasury commission consists of n parties inwards the network, together with requires m out of n parties to handgrip earlier accessing funds. But how large should m together with n be? Large committees are problematic for scaling. To trim the size of committees, the newspaper proposes trusted executions, such equally the Intel SGX enclave. The enclaves guards against software hardware attacks, together with uses trusted execution environments (tees) to secure commission members. The newspaper does non bring tees equally the entire solution, because closed to attacks, similar foreshadow could nonetheless locomote possible amongst tees. Instead, the newspaper uses tees to increase the assault costs together with combines tees amongst treasury committees to solve the work securely.
OK, how does the treasury commission keep agreement? Chain replication is used for propagating the transactions to the committee. Even though the commission members purpose tees, they produce non dominion out that closed to nodes tin nonetheless locomote byzantine, together with thus at that spot is an m-out-of-n understanding at the end. If chain replication is applied naively, closed to attacks are possible. So Teechain uses a variant called force-freeze chain replication, where if the chain configuration is changed or if at that spot is a fault, the determination is an abort decision, together with the dry reason is dumped.
The newspaper includes evaluations to exhibit that Teechain scales out. Evaluations were done using a consummate graph together with a hub-spoke graph. For commission sizes n=3 or iv are used, together with it was shown that 1 1000000 tx/sec are possible using xxx machines.
Teechain is available equally opensource from https://github.com/lsds/Teechain.
In 2018, I had written a review of the stellar arxiv newspaper I read on Stellar. This newspaper extends that amongst formal verification, evaluation, together with lessons learned from several years inwards deployment.
However, the presentation was non technical. It was a really high marker presentation that avoided the description of the protocol together with formal verification. I mean value the presenter, David, must take hold done this presentation hundred times earlier to VCs because the presentation was pitch perfect. Every criticism possible most the protocol was proactively flipped together with explained equally an advantage. Here is how the presentation went.
Things nosotros bring for granted, such equally a banking enterprise concern human relationship inwards a stable currency, access to well-regulated investments, inexpensive international money transfers, globally accepted fee-free credit cards, are non available inwards many places. Stellar provides to a greater extent than equitable access to assets. It is the kickoff solution to provide:
The Byzantine understanding inwards Stellar follows from this hypothesis. The key thought is that the broadcast protocol steps are conditioned on other nodes' steps: bring the footstep if all nodes are mutually satisfied. For availability must generalize follows to a sets of peers, called quorum slices. A quorum is a laid of nodes that contains 1 spell from nonfaulty server.
Stellar has pinnacle tier, view tier, leafage tier servers. As inwards Internet, no key potency appoints the pinnacle tier. The production network has been running for iv years.
In the Q&A period, 1 query was: "How are y'all dealing amongst dynamic reconfiguration of quorums?" David said "we decease it for free, together with tin unilaterally alter quorum slices at whatever time". But this reply is non clear to me because reconfiguration could trim your safety. As far equally I think from the Stellar arxiv report, the onus is on the user to figure out that her quorum slices are laid correctly. So the reconfiguration should locomote to a greater extent than involved than that.
Another query was: "Can y'all produce smartcontracts where dry reason lies inwards unlike slices?" David claimed it is possible, precisely in 1 lawsuit to a greater extent than without reading the newspaper I don't empathize this answer. The dry reason could locomote partitioned (and non fully replicated) across all nodes, together with ordering across all slices may locomote involved.
Smartphones endure from bugs together with attacks. So hardware wallets (or cryptocurrency wallets) are adopted for transaction approving for critical fiscal transactions. The ledger app shop contains 50+ 3rd political party apps. Unfortunately, existing hardware wallets besides take hold OS bugs together with potential hardware bugs equally well.
The contribution inwards this newspaper is to innovate "notary", a device for secure transaction approval. Notary uses an agent separation architecture. And the authors take hold developed a physical hardware wallet paradigm for notary.
The separation architecture provides isolation: at that spot is a centre system-on-chip (soc) together with a course of study agent soc. The centre soc does non run whatever 3rd political party code. It is the agent soc that runs third-party code. The agent soc does non take hold access to OS. The agent besides does non take hold total access to hardware, equally it lacks access to the persistent storage.
There are exclusively 2 wires across the centre soc together with agent soc: UART together with RST. Using RST, the centre tin reset the agent soc. More specifically, the centre clears the dry reason inwards agent soc after every transaction. This agency notary uses clean-state deterministic start to ensure noninterference across transactions, together with avoid whatever bugs/attacks.
Verilog is used for verifying that notary clears registers nether whatever path. SMT-compatible format is used for symbolic circuit simulation. They developed a RISC-V based prototype, together with evaluated amongst 2 agents: Bitcoin together with web-app approval.
Teechain: A Secure Payment Network amongst Asynchronous Blockchain Access
This newspaper is past times Joshua Lind (Imperial College London), Oded Naor (Technion), Ittay Eyal (Technion), Florian Kelbert (Imperial College London), Emin Gun Sirer (Cornell University), Peter Pietzuch (Imperial College London).Bitcoin's throughput is a measly iv transactions per minute equally express past times Nakamoto consensus. This leads to hand off-chain scaling via payment networks, e.g. To found a multihop connectedness these pairwise connections are utilized equally intermediaries. There are iii phases to a payment network: setup a multihop connection, procedure payments for closed to time, perform a short town where the concluding remainder is written dorsum to the blockchain.
To guard against a roll-back assault together with ensure that the right remainder is written, the blockchain is used equally the origin of trust. If a node misbehaves, writes an wrong amount, the other reacts inside delta time, corrects past times providing proof of lightning transactions, resolves the situation, and gets incentive for it.
The work amongst this is that the reaction fourth dimension delta requires synchronous access. Spam/congestion attacks tin brand closed to transactions bring to a greater extent than than vii days to locomote written to the chain. So what should locomote the appropriate value of delta, the reaction time? Security of the payment channel should non rely on read/write latencies.
To address this issue, the newspaper proposes Teechain, the kickoff asynchronous blockchain access payment network. Teechain removes the blockchain equally root-of trust past times introducing closed to other origin of trust, a treasury. Treasury controls funds, balances, together with payments. But how produce nosotros realize treasuries for blockchains, avoiding centralization together with trust?
Teechain uses committees for realizing treasuries for blockchains. A treasury commission consists of n parties inwards the network, together with requires m out of n parties to handgrip earlier accessing funds. But how large should m together with n be? Large committees are problematic for scaling. To trim the size of committees, the newspaper proposes trusted executions, such equally the Intel SGX enclave. The enclaves guards against software hardware attacks, together with uses trusted execution environments (tees) to secure commission members. The newspaper does non bring tees equally the entire solution, because closed to attacks, similar foreshadow could nonetheless locomote possible amongst tees. Instead, the newspaper uses tees to increase the assault costs together with combines tees amongst treasury committees to solve the work securely.
OK, how does the treasury commission keep agreement? Chain replication is used for propagating the transactions to the committee. Even though the commission members purpose tees, they produce non dominion out that closed to nodes tin nonetheless locomote byzantine, together with thus at that spot is an m-out-of-n understanding at the end. If chain replication is applied naively, closed to attacks are possible. So Teechain uses a variant called force-freeze chain replication, where if the chain configuration is changed or if at that spot is a fault, the determination is an abort decision, together with the dry reason is dumped.
The newspaper includes evaluations to exhibit that Teechain scales out. Evaluations were done using a consummate graph together with a hub-spoke graph. For commission sizes n=3 or iv are used, together with it was shown that 1 1000000 tx/sec are possible using xxx machines.
Teechain is available equally opensource from https://github.com/lsds/Teechain.
Fast together with Secure Global Payments amongst Stellar
This newspaper is past times Marta Lokhava (Stellar), Giuliano Losa (Galois), David Mazières (Stanford), Graydon Hoare (Stellar), Nicolas Barry (Stellar), Eliezer Gafni (UCLA), Jonathan Jove (Stellar), Rafał Malinowski (Stellar), Jed McCaleb (Stellar).In 2018, I had written a review of the stellar arxiv newspaper I read on Stellar. This newspaper extends that amongst formal verification, evaluation, together with lessons learned from several years inwards deployment.
However, the presentation was non technical. It was a really high marker presentation that avoided the description of the protocol together with formal verification. I mean value the presenter, David, must take hold done this presentation hundred times earlier to VCs because the presentation was pitch perfect. Every criticism possible most the protocol was proactively flipped together with explained equally an advantage. Here is how the presentation went.
Things nosotros bring for granted, such equally a banking enterprise concern human relationship inwards a stable currency, access to well-regulated investments, inexpensive international money transfers, globally accepted fee-free credit cards, are non available inwards many places. Stellar provides to a greater extent than equitable access to assets. It is the kickoff solution to provide:
- open membership
- issuer-enforced finality: nonetheless postulate secure servers, precisely issuer owns or designates them
- cross-issuer atomicity
The Byzantine understanding inwards Stellar follows from this hypothesis. The key thought is that the broadcast protocol steps are conditioned on other nodes' steps: bring the footstep if all nodes are mutually satisfied. For availability must generalize follows to a sets of peers, called quorum slices. A quorum is a laid of nodes that contains 1 spell from nonfaulty server.
Stellar has pinnacle tier, view tier, leafage tier servers. As inwards Internet, no key potency appoints the pinnacle tier. The production network has been running for iv years.
In the Q&A period, 1 query was: "How are y'all dealing amongst dynamic reconfiguration of quorums?" David said "we decease it for free, together with tin unilaterally alter quorum slices at whatever time". But this reply is non clear to me because reconfiguration could trim your safety. As far equally I think from the Stellar arxiv report, the onus is on the user to figure out that her quorum slices are laid correctly. So the reconfiguration should locomote to a greater extent than involved than that.
Another query was: "Can y'all produce smartcontracts where dry reason lies inwards unlike slices?" David claimed it is possible, precisely in 1 lawsuit to a greater extent than without reading the newspaper I don't empathize this answer. The dry reason could locomote partitioned (and non fully replicated) across all nodes, together with ordering across all slices may locomote involved.
Notary: A Device for Secure Transaction Approval
This newspaper is past times Anish Athalye (MIT CSAIL), Adam Belay (MIT CSAIL), Frans Kaashoek (MIT CSAIL), Robert Morris (MIT CSAIL), Nickolai Zeldovich (MIT CSAIL).Smartphones endure from bugs together with attacks. So hardware wallets (or cryptocurrency wallets) are adopted for transaction approving for critical fiscal transactions. The ledger app shop contains 50+ 3rd political party apps. Unfortunately, existing hardware wallets besides take hold OS bugs together with potential hardware bugs equally well.
The contribution inwards this newspaper is to innovate "notary", a device for secure transaction approval. Notary uses an agent separation architecture. And the authors take hold developed a physical hardware wallet paradigm for notary.
The separation architecture provides isolation: at that spot is a centre system-on-chip (soc) together with a course of study agent soc. The centre soc does non run whatever 3rd political party code. It is the agent soc that runs third-party code. The agent soc does non take hold access to OS. The agent besides does non take hold total access to hardware, equally it lacks access to the persistent storage.
There are exclusively 2 wires across the centre soc together with agent soc: UART together with RST. Using RST, the centre tin reset the agent soc. More specifically, the centre clears the dry reason inwards agent soc after every transaction. This agency notary uses clean-state deterministic start to ensure noninterference across transactions, together with avoid whatever bugs/attacks.
Verilog is used for verifying that notary clears registers nether whatever path. SMT-compatible format is used for symbolic circuit simulation. They developed a RISC-V based prototype, together with evaluated amongst 2 agents: Bitcoin together with web-app approval.
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