前一篇文章: 搭建你的第一个区块链网络(二)
对于区块链系统来说，密码学是必不可少的，因此加密与解密也是核心操作，而密钥通常使用钱包进行保存，这一节我们完成钱包的设计。这一节比较简单。
在比特币网络中，使用的是非对称加密算法，密钥是通过椭圆曲线算法实现的，而本文中，暂且使用RSA算法进行实现，后期再对椭圆曲线算法进行添加。
首先是RSA算法的工具类，参考这里.整理成以下方法:
#RSAKey.java
@Getter
@Setter
public?final?class?RSAKey?{
?????//非对称密钥算法
?????public?static?final?String?KEY_ALGORITHM?=?"RSA";
?????/**
??????*?密钥长度必须是64的倍数，在512到65536位之间
??????*/
?????private?static?final?int?KEY_SIZE?=?512;
?????//公钥
?????private?static?final?String?PUBLIC_KEY?=?"RSAPublicKey";
?
?????//私钥
?????private?static?final?String?PRIVATE_KEY?=?"RSAPrivateKey";
????private?byte[]?privateKey;
????private?byte[]?publicKey;
????private?String?address;
????private?RSAKey()?{
????}
????/**
?????*?生成密钥
?????*/
????public?static?RSAKey?GenerateKeyPair()?throws?Exception?{
????????RSAKey?key?=?new?RSAKey();
????????Map<String,?Object>?keyPair?=?key.initKey();
????????Key?pk?=?(Key)?keyPair.get(PRIVATE_KEY);
????????key.setPrivateKey(pk.getEncoded());
????????pk?=?(Key)keyPair.get(PUBLIC_KEY);
????????key.setPublicKey(pk.getEncoded());
????????return?key;
????}
????private?Map<String,?Object>?initKey()?throws?Exception?{
????????//实例化密钥生成器
????????KeyPairGenerator?keyPairGenerator?=?KeyPairGenerator.getInstance(KEY_ALGORITHM);
????????//初始化密钥生成器
????????keyPairGenerator.initialize(KEY_SIZE);
????????//生成密钥对
????????KeyPair?keyPair?=?keyPairGenerator.generateKeyPair();
????????//公钥
????????RSAPublicKey?publicKey?=?(RSAPublicKey)?keyPair.getPublic();
????????//私钥
????????RSAPrivateKey?privateKey?=?(RSAPrivateKey)?keyPair.getPrivate();
????????//将密钥存储在map中
????????Map<String,?Object>?keyMap?=?new?HashMap<String,?Object>();
????????keyMap.put(PUBLIC_KEY,?publicKey);
????????keyMap.put(PRIVATE_KEY,?privateKey);
????????return?keyMap;
????}
????/**
?????*?私钥加密
?????*
?????*?@param?data?待加密数据
?????*?@param?key???????密钥
?????*?@return?byte[]?加密数据
?????*/
????public?static?byte[]?encryptByPrivateKey(byte[]?data,byte[]?pk)?throws?Exception?{
????????//取得私钥
????????PKCS8EncodedKeySpec?pkcs8KeySpec?=?new?PKCS8EncodedKeySpec(pk);
????????KeyFactory?keyFactory?=?KeyFactory.getInstance(KEY_ALGORITHM);
????????//生成私钥
????????PrivateKey?privateKey?=?keyFactory.generatePrivate(pkcs8KeySpec);
????????//数据加密
????????Cipher?cipher?=?Cipher.getInstance(keyFactory.getAlgorithm());
????????cipher.init(Cipher.ENCRYPT_MODE,?privateKey);
????????return?cipher.doFinal(data);
????}
???/**
????*?公钥解密
????*
????*?@param?data?待解密数据
????*?@param?key??密钥
????*?@return?byte[]?解密数据
????*/
????public?static?byte[]?decryptByPublicKey(byte[]?data,byte[]?pk)?throws?Exception?{
????????//实例化密钥工厂
????????KeyFactory?keyFactory?=?KeyFactory.getInstance(KEY_ALGORITHM);
????????//初始化公钥
????????//密钥材料转换
????????X509EncodedKeySpec?x509KeySpec?=?new?X509EncodedKeySpec(pk);
????????//产生公钥
????????PublicKey?pubKey?=?keyFactory.generatePublic(x509KeySpec);
????????//数据解密
????????Cipher?cipher?=?Cipher.getInstance(keyFactory.getAlgorithm());
????????cipher.init(Cipher.DECRYPT_MODE,?pubKey);
????????return?cipher.doFinal(data);
????}
}
接下来创建钱包实例，对于用户的钱包，需要一下属性:
目前，暂时将钱包设置为单例模式，同时一个钱包中只含有一对密钥对:
#Wallet.java
@Getter
@Setter
public?class?Wallet?{
//单例模式的Wallet
????private?static?Wallet?wallet;
//私钥
????private?byte[]?privateKey;
//公钥
????private?byte[]?publicKey;
//地址
????private?String?address;
????private?Wallet()?throws?Exception?{
????????RSAKey?key??=?RSAKey.GenerateKeyPair();
????????this.privateKey?=?key.getPrivateKey();
????????this.publicKey?=?key.getPublicKey();
????????this.address?=?generateAddress();
????}
????public?static?Wallet?getInstance()?throws?Exception?{
????????if?(wallet?==?null)?{
????????????synchronized?(Wallet.class)?{
????????????????if?(wallet?==?null)?{
????????????????????wallet?=?new?Wallet();
????????????????}
????????????}
????????}
????????return?wallet;
????}
}
接下来是加密与解密操作，只需要包装一下工具类即可:
#Wallet.java
????/**
?????*?加密数据
?????*/
????public?String?encrypt(byte[]?data)?throws?Exception?{
????????byte[]?encry?=?RSAKey.encryptByPrivateKey(data,this.privateKey);
????????return?Hex.encodeHexString(encry);
????}
????/**
?????*??解密数据
?????*/
????public?byte[]?decrypt(String?encry)?throws?DecoderException,?Exception?{
????????return?RSAKey.decryptByPublicKey(Hex.decodeHex(encry),this.publicKey);
????}
还有重要的签名与验证签名的操作:
签名的本质实际上就是哈希操作+加密操作。
#Wallet.java
????/**
?????*?签名数据
?????*/
????public?String?sign(byte[]?data)?throws?Exception?{
????????//原文首先进行哈希
????????String?hash?=?Util.getSHA256(
????????????Hex.encodeHexString(data));
????????//哈希值进行加密
????????String?sign?=?encrypt(
????????????Hex.decodeHex(hash));
????????//原文+encry(hash(原文))
????????return?Hex.encodeHexString(data)+"%%%"+sign;
????}
在这里，我们简单使用%%%将两部分数据进行组合。
至于数字签名的验证则可以分析了：
#Wallet.java
????/**
?????*?验证签名
?????*/
????public?boolean?verify(String?data)?throws?DecoderException,?Exception?{
????????String[]?str?=?data.split("%%%");
????????//?原文?????encry(hash(原文))
????????if(str.length!=2){
????????????return?false;
????????}
????????String?hash?=?Util.getSHA256(str[0]);
????????String?hash2?=?Hex.encodeHexString(this.decrypt(str[1]));
????????if(hash.equals(hash2)){
????????????return?true;
????????}
????????return?false;
????}
对于钱包地址，比特币是有自己的一套生成地址的算法，步骤相对比较繁杂，在本文中，简单使用哈希操作模拟地址的生成。
#Wallet.java
????/**
?????*?根据密钥生成地址
?????*/
????private?String?generateAddress()?throws?NoSuchAlgorithmException?{
????????String?pk?=?Hex.encodeHexString(this.publicKey);
????????this.address?=?"R"?+?Util.getSHA256(pk)?+?Util.getSHA256(Util.getSHA256(pk));
????????return?this.address;
????}
????/**
?????*?获取地址
?????*?@return
?????*?@throws?NoSuchAlgorithmException
?????*/
????public?String?getAddress()?throws?NoSuchAlgorithmException?{
????????return?this.generateAddress();
????}
所有的一切都已经完成，测试一下:
#KeyTest.java
public?class?KeyTest?{
????public?static?void?main(String[]?args)?throws?DecoderException,?Exception?{
????????Wallet?wallet??=?Wallet.getInstance();
????????System.out.println("private?Key:??"+Hex.encodeHexString(wallet.getPrivateKey()));
????????System.out.println();
????????System.out.println("public?Key:??"+Hex.encodeHexString(wallet.getPublicKey()));
????????System.out.println(
????????????wallet.verify(
????????????????wallet.sign("test".getBytes())));
????????System.out.println("address:?"+wallet.getAddress());
????}
}
看起来一切都没有问题:
private Key: 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
public Key: 305c300d06092a864886f70d0101010500034b003048024100b204075a20a86a8773681a2bee6574a68d1028516577c80f22d1f693dbc1c70cca59d95a74b8c7a55c3e02801ebdb025272f1df18ca862701b640a6bc444b7e50203010001
true
address: R92439f4d205def0794e23f626cf61013d04ccf1fdf9106ff78ca3ec30f7bc7cad4cdc346ee44501831c67085a54463e4ffd774654a2bd9328a382652de663f1a
到此为止我们开发了区块链系统的部分功能，距离完成还有很长一段距离。不过，先完成一个比较小的功能好了，即与用户进行交互的操作。之前考虑过使用curl，不过看到了apache的cli工具，所以决定使用这个了。其实就是一种命令行解析工具，根据输入的命令解析后执行对应的功能。参考这里
所以需要在pom.xml添加一下字段导包:
????????<dependency>
????????????<groupId>commons-cli</groupId>
????????????<artifactId>commons-cli</artifactId>
????????????<version>1.2</version>
????????</dependency>
整个步骤分为三个阶段: 定义，解析，询问。
首先需要定义一些参数信息，作为应用程序的接口。
//创建Options对象
????????Options?options?=?new?Options();
//添加-h参数。 h为参数简单形式，help为参数复杂形式，false定义该参数不需要额外的输入，Print help为参数的介绍
????????Option?opt?=?new?Option("h",?"help",?false,?"Print?help");
//定义该参数是否为必须的
????????opt.setRequired(false);
????????options.addOption(opt);
由CLi对用户输入的命令行进行解析。
HelpFormatter?hf?=?new?HelpFormatter();
????????hf.setWidth(110);
? CommandLine?commandLine?=?null;
????????CommandLineParser?parser?=?new?PosixParser();
????????try?{
????????????commandLine?=?parser.parse(options,?args);
//如果含有参数h，则打印帮助信息
if (commandLine.hasOption(‘h‘)) {
// 打印使用帮助
hf.printHelp("Jchain", options, true);
}
...
}catch(Exception e){
}
CommandLineParser 类中定义的 parse 方法将用 CLI 定义阶段中产生的 Options 实例和一组字符串作为输入，并返回解析后生成的 CommandLine。
CLI 解析阶段的目标结果就是创建 CommandLine 实例。
该阶段是根据输入的参数决定进入哪一个逻辑分支中。
? Option[]?opts?=?commandLine.getOptions();
????????????if?(opts?!=?null)?{
????????????????for?(Option?opt1?:?opts)?{
//name为参数名称
????????????????????String?name?=?opt1.getLongOpt();
//如果有额外的参数则传入value中
????????????????????String?value?=?commandLine.getOptionValue(name);
//...根据name指定具体的逻辑分支
}
}
分析完了，然后制定需要的参数好了:
这里指定了三个参数:s,a,w，分别为获取区块链实例，添加区块以及获取钱包实例的功能。
????????opt?=?new?Option("s",?"start",?false,?"start?blockchain");
????????opt.setRequired(false);
????????options.addOption(opt);
????????opt?=?new?Option("a",?"add",?true,?"add?block");
????????opt.setRequired(false);
????????options.addOption(opt);
????????opt?=?new?Option("w",?"wallet",?false,?"init?wallet");
????????opt.setRequired(false);
????????options.addOption(opt);
然后是具体的逻辑分支:
if?(name.equals("s")?||?name.equals("start"))?{
System.out.println(Blockchain.getInstance().block.toString());
}
if(name.equals("a")||name.equals("add")&&value!=""){
System.out.println(Blockchain.getInstance().addBlock(value).toString());
}?
if(name.equals("w")||name.equals("wallet")){
Wallet?wallet?=?Wallet.getInstance();
System.out.println("private?Key:??"+Hex.encodeHexString(wallet.getPrivateKey()));
System.out.println();
System.out.println("public?Key:??"+Hex.encodeHexString(wallet.getPublicKey()));
}?
简单测试一下是否正常工作:
#CliTest.java
public?class?CliTest?{
????public?static?void?main(String[]?args){
????????String[]?str?=?{"-s","-w","-a","block"};
????????//?String[]?str?=?{"-h"};
????????Cli.Start(str);
????}
}
看起来没有问题，获得了高度为4的区块链实例。也成功创建了钱包打印出公私钥。
最后生成了高度为5的区块 区块信息为我们输入的"block"。
Current Last Block num is:4
{"blkNum":4,"curBlockHash":"0000287895ae8f4e4fc781137adee2b2fd0da4d7be3abb68c04507979157eb70","data":"block","nonce":121263,"prevBlockHash":"00003ae4ca11f2dd6262d9218ffe6a98416b4e9e2ad789b39aef74b383cc96a6","timeStamp":"2020-05-17 14:28:16"}
private Key: 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
public Key: 305c300d06092a864886f70d0101010500034b00304802410082a46b7f68d835b5e8047b8794cfd4d5daf4b6f3d8258a8a78f670052f35bab562f52aa7a6eeeb69bc14e03f0d8019db5b754d68e8d0918aa6f2f4b636ba0f070203010001
{"blkNum":5,"curBlockHash":"000047e8fc13a5fe0404aeca104f8624581738361f12f2a8c07c4f172dde62cc","data":"block","nonce":67701,"prevBlockHash":"0000287895ae8f4e4fc781137adee2b2fd0da4d7be3abb68c04507979157eb70","timeStamp":"2020-05-17 16:27:29"}
Github地址：Jchain
原文：https://www.cnblogs.com/cbkj-xd/p/12905706.html