Practical notes on Enterprise software systems and the economics of software.
...by Daniel Szego
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"On a long enough timeline we will all become Satoshi Nakamoto.."
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Daniel Szego
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Wednesday, February 10, 2021
Friday, December 25, 2020
Viewing channel transaction and genesis block in Hyperledger Fabric
Viewing the content of the genesis block with configtxgen:
configtxgen -inspectBlock genesis.block
With configtxlator, you have to start the tool first:
configtxlator start
Viewing the content of the genesis block with configtxlator:
Viewing the content of the channel.tx with configtxlator:
curl -X POST --data-binary @mychannel.tx http://127.0.0.1:7059/protolator/decode/common.Envelope > mychannel.json
Viewing the content of the anchor transaction Org1MSPanchor.tx with configtxlator:
curl -X POST --data-binary @Org1MSPanchors.tx http://127.0.0.1:7059/protolator/decode/common.Envelope > Org1MSPanchors.json
Hyperledger Fabric CLI commands summarized
Some of the most important Fabric CLI commands are the followings.
Create channel:
peer channel create
Fetching block and channel information, it is required at new peer joining the netwotk:
peer channel fetch
Joining the channel:
peer channel join
Listing channels:
peer channel list
Updating channels: (like at sending anchor peer update)
peer channel update
Package chanincode:
peer lifecycle chaincode package
Installing chaincode (must be executed at each peer):
lifecycle chaincode install
Query installed chaincode
lifecycle chaincode install
Approve chaincode (it must be executed at each organisation)
peer lifecycle chaincode approveformyorg
Check if chaincode is ready for the commitment
lifecycle chaincode checkcommitreadiness
Committing chaincode
peer lifecycle chaincode commit
Check if chaincode is committed
peer lifecycle chaincode querycommitted
Invoking chaincode
peer chaincode invoke
Query chaincode
peer chaincode query
Friday, November 27, 2020
On decentralized artificial intelligence markets
At a conference, I was recently asked what I think is the most disruptive technology in the world at the moment. I chose without hesitation, and perhaps surprisingly, I didn’t choose quantum computing, IoT, or even the blockchain, but decentralized artificial intelligence markets.
Wednesday, October 28, 2020
CA backup and recovery in Hyperledger Fabric
Certificate Authority (CA) plays a critical role in production Hyperledger Fabric networks although this role is not always visible for the first sight. Some of the important characteristics:
- CA is not necessary to run continuously in the Hyperledger Farm
- in case CA is down no new certificate can be registered or rolled in, but the remaining of the farms works further without error.
- If the CA database is faulty or lost, no new certificate enrollment can be done for already registered users.
- If the CA database user information is compromised, attackers might enroll new certificates for existing logins.
Wednesday, October 7, 2020
Off-chain computation via Oracle
Friday, October 2, 2020
Ethereum solidity security tools summarized
Security in solidity - Ethereum has been always one of the most important topic. Some of the current most important tools are the followings:
SWC Registry /
Smart Contract Weakness Classification and Test Cases
Ethereum Smart Contract Security Best Practices
https://consensys.github.io/smart-contract-best-practices/
MythX - a cool tool for getting information on solidity smart contract vulnerabilities
EthLint - an open source tool for analyzing Ethereum smart contracts.
https://github.com/duaraghav8/Ethlint
Slither - for making static code analysis on solidity contracts
https://github.com/crytic/slither
Hydra - framework for security and bug bounties
https://github.com/IC3Hydra/Hydra
How to get test DAI on Kovan