go-blockchain, v1.0

The library that implements models and algorithms of blockchain.

Major version. Implementing blocks and their validators (including the proof of work algorithm).

Features

• models:
  • block:
    • storing:
      • timestamp;
      • custom data;
      • hash;
      • previous hash;
    • operations:
      • creation (using a proofer);
      • getting merged data;
      • self-validation (using a proofer);
  • genesis block:
    • based on a usual block without a previous hash;
• proofers:
  • operations:
    • block hashing;
    • block validation;
  • kinds:
    • simple:
      • based on once hashing by the SHA-256 algorithm;
    • proof of work:
      • based on the Hashcash algorithm;
      • additional storing in a block (in a hash actually):
        • nonce;
        • target bit.

Installation

Prepare the directory:

$ mkdir --parents "$(go env GOPATH)/src/github.com/thewizardplusplus/"
$ cd "$(go env GOPATH)/src/github.com/thewizardplusplus/"

Clone this repository:

$ git clone https://github.com/thewizardplusplus/go-blockchain.git
$ cd go-blockchain

Install dependencies with the dep tool:

$ dep ensure -vendor-only

Examples

blockchain.Block:

package main

import (
    "encoding/json"
    "fmt"
    "time"

    "github.com/thewizardplusplus/go-blockchain"
    "github.com/thewizardplusplus/go-blockchain/proofers"
)

type StringHasher string

func (hasher StringHasher) Hash() string {
    return string(hasher)
}

func main() {
    timestamp := time.Date(2006, time.January, 2, 15, 4, 5, 0, time.UTC)
    dependencies := blockchain.Dependencies{
        // use the custom clock function to get the same blocks
        Clock: func() time.Time {
            timestamp = timestamp.Add(time.Hour)
            return timestamp
        },
        Proofer: proofers.ProofOfWork{TargetBit: 248},
    }

    blocks := []blockchain.Block{
        blockchain.NewGenesisBlock(StringHasher("genesis block"), dependencies),
    }
    for i := 0; i < 5; i++ {
        blocks = append(blocks, blockchain.NewBlock(
            StringHasher(fmt.Sprintf("block #%d", i)),
            blocks[len(blocks)-1],
            dependencies,
        ))
    }

    blocksBytes, _ := json.MarshalIndent(blocks, "", "  ")
    fmt.Println(string(blocksBytes))

    // Output:
    // [
    //   {
    //     "Timestamp": "2006-01-02T16:04:05Z",
    //     "Data": "genesis block",
    //     "Hash": "248:225:00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
    //     "PrevHash": ""
    //   },
    //   {
    //     "Timestamp": "2006-01-02T17:04:05Z",
    //     "Data": "block #0",
    //     "Hash": "248:198:0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
    //     "PrevHash": "248:225:00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T18:04:05Z",
    //     "Data": "block #1",
    //     "Hash": "248:15:002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
    //     "PrevHash": "248:198:0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T19:04:05Z",
    //     "Data": "block #2",
    //     "Hash": "248:136:003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
    //     "PrevHash": "248:15:002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T20:04:05Z",
    //     "Data": "block #3",
    //     "Hash": "248:65:00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
    //     "PrevHash": "248:136:003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T21:04:05Z",
    //     "Data": "block #4",
    //     "Hash": "248:173:00b6863763acd6ec77ca3521589d8e68c118efe855657d702783e8e6aee169a9",
    //     "PrevHash": "248:65:00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa"
    //   }
    // ]
}

Repository

Link: https://github.com/thewizardplusplus/go-blockchain/tree/v1.0.

Content: code.

License: MIT.