go-blockchain, v1.2

The library that implements models and algorithms of blockchain.

Implementing a block group abstraction with self-validation; supporting the two modes of its validation: as a full blockchain and as a blockchain chunk.

Change Log

• models:
  • block group:
    • storing:
      • group of blocks;
    • operations:
      • self-validation (using a proofer):
        • modes:
          • as a full blockchain;
          • as a blockchain chunk;
        • takes into account a prepended chunk;
        • allows empty block groups.

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;
  • block group:
    • storing:
      • group of blocks;
    • operations:
      • self-validation (using a proofer):
        • modes:
          • as a full blockchain;
          • as a blockchain chunk;
        • takes into account a prepended chunk;
        • allows empty block groups;
  • blockchain:
    • storing:
      • storage;
      • last block;
    • operations:
      • creation:
        • loading the last block from the storage;
        • when the storage is empty:
          • creation a genesis block using a proofer;
          • storing the genesis block to the storage;
      • adding a block:
        • creation a block using a proofer;
        • storing the block to the storage;
• 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;
• storages:
  • operations:
    • loading the last block;
    • storing a block;
  • kinds:
    • memory storage:
      • storing blocks in memory;
      • additional operations:
        • getting the stored blocks.

Examples

blockchain.BlockGroup:

package main

import (
    "fmt"
    "log"
    "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)
    blockChunks := []blockchain.BlockGroup{
        // chunk #0
        {
            {
                Timestamp: timestamp.Add(6 * time.Hour),
                Data:      StringHasher("block #4"),
                Hash: "248:" +
                    "173:" +
                    "00b6863763acd6ec77ca3521589d8e68c118efe855657d702783e8e6aee169a9",
                PrevHash: "248:" +
                    "65:" +
                    "00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
            },
            {
                Timestamp: timestamp.Add(5 * time.Hour),
                Data:      StringHasher("block #3"),
                Hash: "248:" +
                    "65:" +
                    "00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
                PrevHash: "248:" +
                    "136:" +
                    "003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
            },
        },

        // chunk #1
        {
            {
                Timestamp: timestamp.Add(4 * time.Hour),
                Data:      StringHasher("block #2"),
                Hash: "248:" +
                    "136:" +
                    "003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
                PrevHash: "248:" +
                    "15:" +
                    "002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
            },
            {
                Timestamp: timestamp.Add(3 * time.Hour),
                Data:      StringHasher("block #1"),
                Hash: "248:" +
                    "15:" +
                    "002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
                PrevHash: "248:" +
                    "198:" +
                    "0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
            },
        },

        // chunk #2
        {
            {
                Timestamp: timestamp.Add(2 * time.Hour),
                Data:      StringHasher("block #0"),
                Hash: "248:" +
                    "198:" +
                    "0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
                PrevHash: "248:" +
                    "225:" +
                    "00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
            },
            {
                Timestamp: timestamp.Add(time.Hour),
                Data:      StringHasher("genesis block"),
                Hash: "248:" +
                    "225:" +
                    "00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
                PrevHash: "",
            },
        },
    }

    var prependedChunk blockchain.BlockGroup
    for index, blockChunk := range blockChunks {
        validationMode := blockchain.AsBlockchainChunk
        if index == len(blockChunks)-1 {
            validationMode = blockchain.AsFullBlockchain
        }

        if !blockChunk.IsValid(
            prependedChunk,
            validationMode,
            blockchain.BlockDependencies{
                Proofer: proofers.ProofOfWork{TargetBit: 248},
            },
        ) {
            log.Fatalf("chunk #%d is incorrect", index)
        }

        prependedChunk = blockChunk
    }

    fmt.Println("all chunks are correct")

    // Output:
    // all chunks are correct
}

Repository

Link: https://github.com/thewizardplusplus/go-blockchain/tree/v1.2.

Content: code.

License: MIT.