doganbolivar / pbft

Implementation of PBFT in node.js

PBFT in Blockchain

Implementation of practical byzantine fault tolerance in blockchain

Accompanying article: https://medium.com/coinmonks/implementing-pbft-in-blockchain-12368c6c9548

Documentation

System configuration

Update the number of nodes in the system by setting the value of NUMBER_OF_NODES in the config.js file.

Update the maximum number of transactions to be stored in a block by setting TRANSACTION_THRESHOLD in config.js file.

Run nodes

Run the nodes using the following commands (assuming that the total nodes are 3)

First node:

SECRET="NODE0" P2P_PORT=5000 HTTP_PORT=3000 node app

Second node:

SECRET="NODE1" P2P_PORT=5001 HTTP_PORT=3001 PEERS=ws://localhost:5000 node app

Third node:

SECRET="NODE2" P2P_PORT=5002 HTTP_PORT=3002 PEERS=ws://localhost:5001,ws://localhost:5000 node app

Note the ports are different since all the nodes are running on the same pc and the PEERS variable contains a comma seperated list of socket addresses neighbouring nodes

Also note that in the ports 300X are HTTP Ports and localhost:300X/endpoint-name should be used to send request to the backend.

Ports 500X are for socket servers and are used to create socket connection between different nodes.

Create transactions

POST /transact

Body - JSON Object

Required Fields

• data - JSON Object

{
	"data": {
		"temporary" : "data"
	}
}

Response

JSON Object with list of transactions

[
    {
        "id": "18017a20-f45c-11ea-a67e-058e0ab7cf36",
        "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
        "input": {
            "data": {
                "temporary": "data"
            },
            "timestamp": 1599848696515
        },
        "hash": "63b805e0e39384bb419ca688846fb806b7a4551c05769c1dd4b5e91b92a3baca",
        "signature": "1375322E39B05C6AE384AFB806FDB874D344E5237A0D4405FF0BE7086F78F6775901C175791AF51F7BF5982385668D67EE144E82DBA8CF7ADCB63FEDA4B5CB02"
    }
]

Create multiple transactions using this end point for any node. All transactions will be distributed among the neighbouring nodes and soon to the entire network. Once the transaction count reach the threshold all node will initiate the consesus protocol.

Get transactions

GET /transactions

Response JSON Object containing list of transactions in the transaction pool.

[
    {
        "id": "af57d900-f45c-11ea-a7ba-79f17df47d35",
        "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
        "input": {
            "data": {
                "temporary": "data"
            },
            "timestamp": 1599848950417
        },
        "hash": "d8adcfd6cd136903266a103e86fe769eb2c2c91620d97c062681f5cbaa4c6fd2",
        "signature": "A91C6F9831509A3844B00CB65ADD13233DD8DF78E210D3AA933FAB6184AC4EA54E46A492DA6B5821BE4782688584EB6402C59C277DFA02B3E0573A50EA800E00"
    },
    {
        "id": "bca80d00-f45c-11ea-a7ba-79f17df47d35",
        "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
        "input": {
            "data": {
                "temporary": "data2"
            },
            "timestamp": 1599848972752
        },
        "hash": "447c710b0e6382a21e220f7688e932369417d8ac8e5e69fee297b800474306af",
        "signature": "ADC5150CD9C1CE4DAFE1623BCB0758271AFCE108768C2FB4C26E8A58DDFC95C99E3972928E90BE87906E2A395004F6A2CEEC691C698073DA27CE9F651EB9990E"
    }
]

Get blocks

After hitting the threshold, the nodes will agree upon a block and add it to the chain. Get the chain using the below end point

GET /blocks

Response JSON Object containing list of blocks

[
    {
        "timestamp": "genesis time",
        "lastHash": "----",
        "hash": "genesis-hash",
        "data": [],
        "proposer": "P4@P@53R",
        "signature": "SIGN",
        "sequenceNo": 0
    },
    {
        "timestamp": 1599849133103,
        "lastHash": "genesis-hash",
        "hash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
        "data": [
            {
                "id": "af57d900-f45c-11ea-a7ba-79f17df47d35",
                "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "input": {
                    "data": {
                        "temporary": "data"
                    },
                    "timestamp": 1599848950417
                },
                "hash": "d8adcfd6cd136903266a103e86fe769eb2c2c91620d97c062681f5cbaa4c6fd2",
                "signature": "A91C6F9831509A3844B00CB65ADD13233DD8DF78E210D3AA933FAB6184AC4EA54E46A492DA6B5821BE4782688584EB6402C59C277DFA02B3E0573A50EA800E00"
            },
            {
                "id": "bca80d00-f45c-11ea-a7ba-79f17df47d35",
                "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "input": {
                    "data": {
                        "temporary": "data2"
                    },
                    "timestamp": 1599848972752
                },
                "hash": "447c710b0e6382a21e220f7688e932369417d8ac8e5e69fee297b800474306af",
                "signature": "ADC5150CD9C1CE4DAFE1623BCB0758271AFCE108768C2FB4C26E8A58DDFC95C99E3972928E90BE87906E2A395004F6A2CEEC691C698073DA27CE9F651EB9990E"
            },
            {
                "id": "1a719a50-f45d-11ea-a7ba-79f17df47d35",
                "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "input": {
                    "data": {
                        "temporary": "data2"
                    },
                    "timestamp": 1599849130101
                },
                "hash": "424dfd403865aeb7a8fbe8fe44d7b892cc8bcb7b67ceb8758497297c0289a80c",
                "signature": "E3A37A14BA56D7FFBA0DF9943E99ACFF71A2C61CE2DB9BE96AB4F4BFD92E1CE9702404542D04FF9F6334F4822D96F7279007A206BD324A3BB785CB4CD667060B"
            },
            {
                "id": "1b743d40-f45d-11ea-a7ba-79f17df47d35",
                "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "input": {
                    "data": {
                        "temporary": "data2"
                    },
                    "timestamp": 1599849131796
                },
                "hash": "fde375143dab525261cfbc32839289816b3414c0e35b5c14f53f1362b579faed",
                "signature": "9BB6152D31356F2ACFDAB740438E529DE2AE8B03660F5C67E6595CC4006B8541674317177772C4FCBD5156EE807F690A930D4682F3DAD300960631A3AC8C8E0C"
            },
            {
                "id": "1c24a180-f45d-11ea-a7ba-79f17df47d35",
                "from": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "input": {
                    "data": {
                        "temporary": "data2"
                    },
                    "timestamp": 1599849132952
                },
                "hash": "37ffe4eabfb49339742e2d07723189b5d861c6e72d96a741270613d9d0f173b7",
                "signature": "2F55E0BC7E177A6738AD1FCB363F6E33AD38802EBB86F29C8E17D30E6FF14BEACE594146581EF97D8D98357468F8E62C9C4A5A2522A58B7DF0F4C94D0109C508"
            }
        ],
        "proposer": "5864f1e7d7e37e95882b398c21ca29b314ebfc6ea1286c8dc1201214cc0d0686",
        "signature": "DDFB628EB5E506EF458CD6D3A788BD459A039130F7ED56D91A6E2FB2EE6E2AC591883E2FF7154CFA4D000900F26E5550B6631E7773BFE2C2D94F854A8A0C5D00",
        "sequenceNo": 1,
        "prepareMessages": [
            {
                "blockHash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
                "publicKey": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "signature": "F3A381CC4DEEBF83D599BA300401EE36D1873FAF2B3F75F7AB5C4588D90CDD5B4C6F728359FA769CC188DEC17DAABC3290B44100E2A71AAEA22E7B8B90024A00"
            },
            {
                "blockHash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
                "publicKey": "a47fc60f15b1e5195c8a03c2ef5d0173efd66bf38c1962f38ac79acb430354c3",
                "signature": "C813A362465D5426F6D736B8A28A2D61B8E9B7B8F5451237346CCC455BF8F79FBE41446665760524E6A4019E3C93DF677D23BBBB470F207063A4534EA79C2108"
            },
            {
                "blockHash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
                "publicKey": "5864f1e7d7e37e95882b398c21ca29b314ebfc6ea1286c8dc1201214cc0d0686",
                "signature": "DDFB628EB5E506EF458CD6D3A788BD459A039130F7ED56D91A6E2FB2EE6E2AC591883E2FF7154CFA4D000900F26E5550B6631E7773BFE2C2D94F854A8A0C5D00"
            }
        ],
        "commitMessages": [
            {
                "blockHash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
                "publicKey": "276ab32fb62ccc18fcb9c0e792092b9b6911e53b75f951211b232cf84de061bf",
                "signature": "F3A381CC4DEEBF83D599BA300401EE36D1873FAF2B3F75F7AB5C4588D90CDD5B4C6F728359FA769CC188DEC17DAABC3290B44100E2A71AAEA22E7B8B90024A00"
            },
            {
                "blockHash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
                "publicKey": "a47fc60f15b1e5195c8a03c2ef5d0173efd66bf38c1962f38ac79acb430354c3",
                "signature": "C813A362465D5426F6D736B8A28A2D61B8E9B7B8F5451237346CCC455BF8F79FBE41446665760524E6A4019E3C93DF677D23BBBB470F207063A4534EA79C2108"
            },
            {
                "blockHash": "857221a4d3f200bb8456b0b0dc90d6da76c3f13230753ea7993c4d3ee8d8a75b",
                "publicKey": "5864f1e7d7e37e95882b398c21ca29b314ebfc6ea1286c8dc1201214cc0d0686",
                "signature": "DDFB628EB5E506EF458CD6D3A788BD459A039130F7ED56D91A6E2FB2EE6E2AC591883E2FF7154CFA4D000900F26E5550B6631E7773BFE2C2D94F854A8A0C5D00"
            }
        ]
    }
]

Final thoughts

This was simplified implementation of PBFT and can be extended further by

1. Combining all pools into one to make a generic pool.
2. Adding STATE variable in the project and update it whenever a new state is reached.
3. Clearing commit, prepare and message pool after every new round to save memory space.
4. Create a registration method in blockchain to add new validators dynamically and handle disconnections.
5. Create a cryptocurrency using this project as a base.
6. Use multi-threading to make this project concurrent and faster.