pow-blockchain

Minimum Blockchain

Supports basic blockchain capabilities such as multi-node Proof-of-Work consensus. It exposes a HTTP API with the following endpoints:

.service(web::resource("/nodes/register").route(web::post().to(register)))
.service(web::resource("/nodes/resolve").route(web::get().to(resolve)))
.service(web::resource("/mine").route(web::get().to(mine)))
.service(web::resource("/chain").route(web::get().to(chain)))
.service(web::resource("/transactions/new").route(web::post().to(transaction)))

Todo:

1. Bootstrap node and node registration broadcasting (currently you have to manually register every node);
2. RPC-based communication;
3. Persistence to disk (currently everything is in-memory);
4. Public-key encryption (right now it's all UUID + sha hashing);
5. Different consensus algorithms such as Proof-of-Stake;
6. Much more validations and assertions;
7. For PoW: configurable and dynamic mining difficulty (right now it's hardcoded);
8. And much more.

Running nodes and interacting with them

To run a node you can use: cargo run -- 8080 where the only argument is the port exposed by that single node.

When running multiple nodes, you must register each one of them manually. For instance, to register 8080 to the 8081 node:

 curl -X POST -d '{"addresses": ["http://localhost:8080"]}' -H "Content-type: application/json" http://localhost:8081/nodes/register

Note that you also have to register 8081 to 8080. This is necessary for the consensus algorithm to work properly; Once their chain differ, they will query each other's chain and pick the longest one.

To query the current chain in a node you can:

curl http://localhost:8080/chain | json_pp
[
   {
      "index" : 1,
      "previous_hash" : "1",
      "proof" : 100,
      "timestamp" : {
         "nanos_since_epoch" : 658139000,
         "secs_since_epoch" : 1622306099
      },
      "transactions" : []
   },
   {
      "index" : 2,
      "previous_hash" : "ECADC938053B0063C9C5ADCA6EBF64B7E8004FD1FB5B196DD782C59D3470213B",
      "proof" : 248000,
      "timestamp" : {
         "nanos_since_epoch" : 191055800,
         "secs_since_epoch" : 1622306146
      },
      "transactions" : [
         {
            "amount" : 1,
            "recipient" : "9509df17-9979-4b36-9942-e8c4cbf09830",
            "sender" : "0"
         }
      ]
   },
   {
      "index" : 3,
      "previous_hash" : "4F80AFD7194667E0AA77FD8FC745CE36BBC19F7C9CCC930D50CC826C4BD39FEF",
      "proof" : 101720,
      "timestamp" : {
         "nanos_since_epoch" : 304410600,
         "secs_since_epoch" : 1622306169
      },
      "transactions" : [
         {
            "amount" : 1,
            "recipient" : "55098877-a3a4-40ee-b68a-1f7e459aa20d",
            "sender" : "0"
         }
      ]
   },
   {
      "index" : 4,
      "previous_hash" : "ACB813083B3026D5A75E1E0FE53A30FEBC3BCC8BAA41FFDFB2938845F9462763",
      "proof" : 1282,
      "timestamp" : {
         "nanos_since_epoch" : 988313400,
         "secs_since_epoch" : 1622306230
      },
      "transactions" : [
         {
            "amount" : 1,
            "recipient" : "9509df17-9979-4b36-9942-e8c4cbf09830",
            "sender" : "0"
         }
      ]
   }
]

To mine

curl -X GET -H "Content-type: application/json" http://localhost:8081/mine

Sender "0" means it's an award for mining.

To send a transaction:

curl -X POST -d '{"amount": 10.0, "sender": "349857dhkfjg", "recipient": "234098dflsdf"}' -H "Content-type: application/json" http://localhost:8080/transactions/new

The transaction will be added to the next mined block.