Category: Blockchain

UnsignedTransaction, SignedTransactionの構造体に、nft_dataと、nft_originを追加する。
nft_dataは、nftとして保存するデータ。
nft_originはnftを発行したトランザクションのhashデータ。
NFTを譲渡する場合は、nft_dataを空にして、nft_originに値を入れる。

#[derive(Serialize, Deserialize, Clone, Debug)]
struct UnsignedTransaction {
    time: String,
    sender: String,
    receiver: String,
    amount: i32,
    nft_data: String,
    nft_origin: String,
}

nft_holderというhashmapを作成して、そこにnftを発行したトランザクションのhashデータと、最後にNTFを譲渡されたreceiverの連想配列を入れていく。
誰が何を持っているかは、トランザクションのhashデータをデコードして、nft_dataの値を取り出す。

#[tokio::main]
async fn main(){

    let mut transaction_pool: Vec<SignedTransaction> = Vec::new();
    let transaction1 = UnsignedTransaction {time:Utc::now().to_string(), sender:"047683c00f6z".to_string(), receiver:"DyH5SHvezz".to_string(), amount: 0, nft_data:"hello world".to_string(),nft_origin:"".to_string()};
    let transaction2 = UnsignedTransaction {time:Utc::now().to_string(), sender:"DyH5SHvezz".to_string(), receiver:"655EFC80ss".to_string(), amount: 0, nft_data:"".to_string(),nft_origin:"eyJ0aW1lIjoiMjAyNS0wMS0xNyAwODoyOTo0Ni42NzgzNDU3OTQgVVRDIiwic2VuZGVyIjoiMDQ3NjgzYzAwZjZ6IiwicmVjZWl2ZXIiOiJEeUg1U0h2ZXp6IiwiYW1vdW50IjowLCJuZnRfZGF0YSI6ImhlbGxvIHdvcmxkIiwibmZ0X29yaWdpbiI6IiJ9".to_string()};
    let transaction3 = UnsignedTransaction {time:Utc::now().to_string(), sender:"047683c00f6z".to_string(), receiver:"DyH5SHvezz".to_string(), amount: 0, nft_data:"Milk Cafe".to_string(),nft_origin:"".to_string()};
    let transaction4 = UnsignedTransaction {time:Utc::now().to_string(), sender:"047683c00f6z".to_string(), receiver:"DyH5SHvezz".to_string(), amount: 1000, nft_data:"".to_string(),nft_origin:"".to_string()};

    // println!("{}", BASE64_STANDARD.encode(serde_json::to_vec(&transaction1.clone()).unwrap()));
    // println!("{}", base64_decode(&str));

    transaction_pool.push(sign_transaction(&transaction1));
    transaction_pool.push(sign_transaction(&transaction2));
    transaction_pool.push(sign_transaction(&transaction3));
    transaction_pool.push(sign_transaction(&transaction4));

    let nft_holder:HashMap<String, String> = nft_calc(transaction_pool);
    for (k, v) in nft_holder {
        let transaction_str = base64_decode(&k);
        let transaction:UnsignedTransaction = serde_json::from_str(&transaction_str).unwrap();
        println!("保有者:{}, NFT:{}", v, transaction.nft_data);
    }
}

fn nft_calc(transaction_pool: Vec<SignedTransaction>) -> HashMap<String, String> {
    let mut nft_holder: HashMap<String, String> = HashMap::new();
    for transaction in transaction_pool {
        if transaction.amount == 0 {
            let transaction_hash: String = BASE64_STANDARD.encode(serde_json::to_vec(&transaction.clone()).unwrap());
            if transaction.nft_origin == "" && transaction.nft_data != "" && (nft_holder.get(&transaction_hash) == None) {
                nft_holder.insert(transaction_hash, transaction.receiver);
            } else if (nft_holder.get(&transaction_hash) == Some(&transaction.sender)) && transaction.nft_data == "" {
                nft_holder.insert(transaction.nft_origin, transaction.receiver);
            }
        }
    }
    return nft_holder
}

Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.13s
Running `target/debug/sample`
保有者:DyH5SHvezz, NFT:hello world
保有者:DyH5SHvezz, NFT:Milk Cafe

これは中々凄いな…

各コインのUSDレートをbitcoinのUSDレートで割れば、スワッピングレートが計算される。
f32のvectorはpartial_cmpで比較してソートする。

let mut coin_rate = get_price().await.unwrap();

    let objs: Vec<Rate> = serde_json::from_value(coin_rate).unwrap();
    let mut btcRate: f32 = 0.0;

    let mut crypt_objs: Vec<Rate> = Vec::new();
    for obj in objs {
        if obj.r#type == "crypto" {
            if obj.symbol == "BTC" {
                crypt_objs.insert(0, obj.clone());
                btcRate = obj.rateUsd.parse::<f32>().unwrap();
            } else {
                crypt_objs.push(obj);
            }   
        }
    }
    println!("{}", &btcRate);

    let mut data: Vec<RateSwap> = vec![];
    for crypt_obj in crypt_objs {
        let obj = RateSwap { id: crypt_obj.id, symbol: crypt_obj.symbol, rateUsd: crypt_obj.rateUsd.clone(), rateBtc: crypt_obj.rateUsd.parse::<f32>().unwrap() / &btcRate };
        data.push(obj);
    }
    data.sort_by(|a, b| a.rateBtc.partial_cmp(&b.rateBtc).unwrap().reverse());

    let mut context = tera::Context::new();
    context.insert("title", "Index page");
    context.insert("data", &data);

おおお、割とやりたいことはできている気がする。
対btcではなく、コイン対コインでスワッピングする場合も同様のロジックで、交換する両方のコインのUSDレートで割ればスワッピングレートが計算できる。

Nice、次はaxumのログイン機能およびDB連携

use std::collections::HashMap;
use chrono::{Utc, Local, DateTime, Date};
use sha2::Sha256;
use sha2::Digest;
use rand::Rng;
use std::io;
use std::io::Error;

#[derive(Debug)]
struct Block {
    index: u32,
    previous_hash: String,
    timestamp: DateTime<Utc>,
    data: Vec<String>,
    validator: String,
    hash: String,
}

#[derive(Debug)]
struct BlockChain {
    chain: Vec<Block>,
    unconfirmed_data: Vec<String>,
    validators: HashMap<String, i32>,
    staked_tokens: Vec<i32>,
}

impl BlockChain {

    const minimum_stake: i32 = 10;

    fn last_block(&self) -> &Block {
        return self.chain.last().unwrap();
    }

    fn add_data(&mut self, new_data:String) {
        self.unconfirmed_data.push(new_data);
    }

    fn add_validator(&mut self, validator: String, stake: i32) {
        if stake >= Self::minimum_stake {
            self.validators.insert(validator, stake);
            self.staked_tokens.push(stake);
        } else {
            println!("{} does not meet the minimum stake requirement.", validator);
        }
    }

    fn select_validator(self) -> String {
        let total_stake: i32 = self.staked_tokens.iter().sum();
        let mut selected_validator: String = "".to_string();
        let mut rnd = rand::thread_rng();
        while selected_validator == "".to_string() {
            let pick = rnd.gen_range(0..total_stake);
            let mut current: i32 = 0;
            for (validator, stake) in &self.validators {
                // println!("{} {}", validator, stake);
                current += stake;
                if current > pick{
                    selected_validator = validator.to_string();
                    break;
                }
            }
        }
        return selected_validator;
    }

    fn create_block(mut self, validator: String)-> Result<(), String> {
        if self.unconfirmed_data.is_empty() {
            return Err("No transaction".to_string());
        }
        let last_block = self.last_block(); 
        let new_block = Block {
            index: last_block.index + 1,
            previous_hash: last_block.hash.clone(),
            timestamp: Utc::now(),
            data : self.unconfirmed_data.clone(),
            validator: validator,
            hash: "".to_string() 
        };
        self.chain.push(new_block);
        self.unconfirmed_data.clear();
        Ok(())
    }

    fn display_chain(self) {
        println!("{:?}", self.chain);
    }

}

fn calculate_hash(data: String) -> String {
    let mut hasher = Sha256::new();
    hasher.update(data);
    let hashed_sha256 = hasher.finalize();
    return hex::encode(hashed_sha256);
}

fn main() {
    let genesis_hash = calculate_hash("Genesis Block".to_string());
    let genesis_block = Block { index: 0, previous_hash: "".to_string(), timestamp: Utc::now(), data: vec!["Genesis Block".to_string()], validator: "".to_string(), hash: genesis_hash };

    let mut blockchain = BlockChain { chain: vec![genesis_block], unconfirmed_data: vec![], validators: HashMap::from([]), staked_tokens: vec![]};

    blockchain.add_validator("Alice".to_string(), 200);
    blockchain.add_validator("Bob".to_string(), 300);
    blockchain.add_validator("Chan".to_string(), 400);

    blockchain.add_data("James got 1000 token".to_string());
    blockchain.add_data("James sent 500 token to Jhon".to_string());

    let selected_validator = blockchain.select_validator();
    println!("Selected validator is {}", selected_validator);
}

Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.02s
Running `target/debug/sample`
Selected validator is Bob

基本的にPythonで書くのとそこまで変わりませんね。

use reqwest::Client;
use serde::{Serialize, Deserialize};
use serde_json::{Value};

#[tokio::main]
async fn main() {

    let btc: String = "BTC".to_string();
    let btc_price: Value = get_price(btc).await.unwrap();
    println!("{}", btc_price);

    let eth: String = "ETH".to_string();
    let eth_price: Value = get_price(eth).await.unwrap();
    println!("{}", eth_price);
}

async fn get_price(code: String) -> Result<Value, Box<dyn std::error::Error>> {
    let mut url:String = "https://api.coinbase.com/v2/exchange-rates?currency=".to_string();
    url.push_str(&code);
    let contents = reqwest::get(url).await?.text().await?;
    let res: Value = serde_json::from_str(&contents).unwrap();
    println!("{:?}", res["data"]["rates"]["USD"]);
    Ok((res["data"]["rates"]["USD"]).clone())
}

Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.97s
Running `target/debug/wallet`
String(“94359.295”)
“94359.295”
String(“3246.82”)
“3246.82”

処理速度が遅いが、取得はできる。
よし、さて、PoSでもやるか！

hex::decode(&public_key_hex)　でdecodeして、さらにfrom_sec1_bytesでpublic keyにします。

    let public_key = secret_key.public_key();
    let public_key_serialized = public_key.to_string();
    println!("Public Key: \n{}", public_key_serialized);

    let public_key_hex = hex::encode(&public_key.to_sec1_bytes());
    println!("hex Public Key: \n{}", public_key_hex);

    let public_key_decode = hex::decode(&public_key_hex).unwrap();
    println!("decode Public Key: \n{:?}", &public_key_decode);

    let public_key = p256::PublicKey::from_sec1_bytes(&public_key_decode).expect("import error");

    println!("decode Public Key: \n{:?}", &public_key);

    let signing_key: SigningKey = secret_key.into();
    let message = b"ECDSA proves knowledge of a secret number in the context of a single message";
    let signature: Signature = signing_key.sign(message);

    let verifying_key: VerifyingKey = public_key.into();
    assert!(verifying_key.verify(message, &signature).is_ok());

$ cargo run
// 省略
hex Public Key:
040b807b5e5fee8c91df858e09aa6dc085eae1b9b70783ce32ec68ad4994f9d16a991e277a1515a22e35d2d7935dec95946f31a2e3ea1e125a9067a177523063b0
decode Public Key:
[4, 11, 128, 123, 94, 95, 238, 140, 145, 223, 133, 142, 9, 170, 109, 192, 133, 234, 225, 185, 183, 7, 131, 206, 50, 236, 104, 173, 73, 148, 249, 209, 106, 153, 30, 39, 122, 21, 21, 162, 46, 53, 210, 215, 147, 93, 236, 149, 148, 111, 49, 162, 227, 234, 30, 18, 90, 144, 103, 161, 119, 82, 48, 99, 176]
decode Public Key:
PublicKey { point: AffinePoint { x: FieldElement(0x3B226D0B94EFABC8980328AB7FE8AE347D418871A770F1EFFE8A24FCAC9EE9DB), y: FieldElement(0x307BB7BAC4B807E9D59F65BEC20EC8AB54591BE07549140238927D01CA9152EF), infinity: 0 } }

おおお、このdecodeと署名の確認は本当に上手くいくのか再度トランザクションを実際に作ってテストする必要がありますね。

### signatureとpublic keyをPostされた側でのverify

    let signed_ut1 = SignedTransaction {time: unsignedtransaction.time, sender: unsignedtransaction.sender, receiver: unsignedtransaction.receiver, amount: unsignedtransaction.amount, signature: sig1.to_string()};
    println!("{:?}", signed_ut1);

    let public_key_decode = hex::decode(&signed_ut1.sender).unwrap();
    let public_key = p256::PublicKey::from_sec1_bytes(&public_key_decode).expect("import error");
    let verifying_key: VerifyingKey = public_key.into();

    let signature: Signature = signed_ut1.signature.parse::<Signature>().unwrap();

    let posted_transaction = UnsignedTransaction { time:signed_ut1.time, sender:signed_ut1.sender, receiver: signed_ut1.receiver, amount: signed_ut1.amount};
    let posted_serialized: String = serde_json::to_string(&posted_transaction).unwrap();

    assert!(verifying_key.verify(posted_serialized.as_bytes(), &signature).is_ok());

おおおおおおお、hexのpublic keyからちゃんと署名の検証ができてます。

自分が持っているblockのサイズと別のノードが持っているブロックサイズを比較して、相手の方が大きければ自分のブロックチェーンを更新する

    let path = "own_blocks.txt";
    let own_blocks = count_lines(path);
    println!("{}", own_blocks);

    let json_data = json();
    let deserialized = json!(**&json_data);
    let objs: Vec<Block> = serde_json::from_value(deserialized).unwrap();
    if objs.len() > own_blocks {
        let mut file = File::create("data/blocks.txt").expect("file not found.");
        for obj in &objs {
            let t = serde_json::to_string(&obj).unwrap();
            writeln!(file, "{}", t).expect("can not write.");
        }
    }
    println!("{}", objs.len());

OK、これを関数化して繋げる。