Java&keytool生成RSA密钥 -

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Java&keytool生成RSA密钥

博客分类：

java基础

java keytool RSA

工作中需要使用非对称加密RSA来进行消息摘要生产和验证，但无法通过keytool工具来提取私钥。

那怎么获得私钥、公钥？

以Java为例：通过KeyStore类getEntry() 或者getKey()来提取私钥；通过Certificate类getPublicKey()获取公钥。

一.Keytool生成KeyStore文件

 --  生成密码仓库test.store
keytool -genkey -v -alias test -dname "CN=test,OU=HE,O=CUI,L=SHENGZHEN,ST=GUANGDONG,C=CN" -keyalg RSA -keysize 2048 -keypass 5201314 -keystore test.store -storepass 5201314 -validity 10000 -storetype JCEKS
 --  导出证书test.crt
keytool -exportcert -alias test -file test.crt -keystore test.store -storepass 5201314 -rfc -storetype JCEKS

运行后在F盘的Key目录下将产生如下两个文件。

二.生成私钥、公钥

KeyStoreHelper.java

package com.bijian.keystore;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.ObjectOutputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;

import sun.misc.BASE64Encoder;

public class KeyStoreHelper {
    
    public static void main(String[] args) throws Exception {
        
        String privatePath = "F:/Key/testPri.key"; // 准备导出的私钥
        String publicPath = "F:/Key/testPub.key"; // 准备导出的公钥
        PrivateKey privateKey = getPrivateKeyFromStore();
        createKeyFile(privateKey, privatePath);
        PublicKey publicKey = getPublicKeyFromCrt();
        createKeyFile(publicKey, publicPath);
        
        byte[] publicKeyBytes = publicKey.getEncoded();
        byte[] privateKeyBytes = privateKey.getEncoded();

        String publicKeyBase64 = new BASE64Encoder().encode(publicKeyBytes);
        String privateKeyBase64 = new BASE64Encoder().encode(privateKeyBytes);

        System.out.println("publicKeyBase64.length():" + publicKeyBase64.length());
        System.out.println("publicKeyBase64:" + publicKeyBase64);

        System.out.println("privateKeyBase64.length():" + privateKeyBase64.length());
        System.out.println("privateKeyBase64:" + privateKeyBase64);
    }

    private static PrivateKey getPrivateKeyFromStore() throws Exception {
        String alias = "test"; // KeyTool中生成KeyStore时设置的alias
        String storeType = "JCEKS"; // KeyTool中生成KeyStore时设置的storetype
        char[] pw = "5201314".toCharArray(); // KeyTool中生成KeyStore时设置的storepass
        String storePath = "F:/Key/test.store"; // KeyTool中已生成的KeyStore文件
        storeType = null == storeType ? KeyStore.getDefaultType() : storeType;
        KeyStore keyStore = KeyStore.getInstance(storeType);
        InputStream is = new FileInputStream(storePath);
        keyStore.load(is, pw);
        // 由密钥库获取密钥的两种方式
        // KeyStore.PrivateKeyEntry pkEntry = (KeyStore.PrivateKeyEntry) keyStore.getEntry(alias, new KeyStore.PasswordProtection(pw));
        // return pkEntry.getPrivateKey();
        return (PrivateKey) keyStore.getKey(alias, pw);
    }

    private static PublicKey getPublicKeyFromCrt() throws CertificateException, FileNotFoundException {
        String crtPath = "F:/Key/test.crt"; // KeyTool中已生成的证书文件
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        FileInputStream in = new FileInputStream(crtPath);
        Certificate crt = cf.generateCertificate(in);
        PublicKey publicKey = crt.getPublicKey();
        return publicKey;
    }

    private static void createKeyFile(Object key, String filePath) throws Exception {
        FileOutputStream fos = new FileOutputStream(filePath);
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(key);
        oos.flush();
        oos.close();
    }
}

运行上面的代码后，将在F盘的Key目录下新产生testPub.key、testPri.key公私钥文件。

并在控制台输出如下内容：

到此为止，公私钥已生成。

三.验证上面生成的公私钥

1.私钥加签公钥验签，进行验证

DigestUtil.java

package com.bijian.keystore;

public class DigestUtil {

    /**
     * 字节转为十六进制字符串
     * @param字节
     * @return 十六进制字符串
     */
    public static String byte2hex(byte[] b) {
        String hs = "";
        String stmp = "";
        for (int n = 0; b != null && n < b.length; n++) {
            stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
            if (stmp.length() == 1)
                hs = hs + "0" + stmp;
            else
                hs = hs + stmp;
        }
        return hs;
    }

    /**
     * 十六进制字符转为字节
     * @param 十六进制字符
     * @return  字节
     */
    public static byte[] hex2byte(byte[] b) {
        if ((b.length % 2) != 0)
            throw new IllegalArgumentException("byte length is not correct");
        byte[] b2 = new byte[b.length / 2];
        for (int n = 0; n < b.length; n += 2) {
            String item = new String(b, n, 2);
            b2[n / 2] = (byte) Integer.parseInt(item, 16);
        }
        return b2;
    }

    /**
     * 字符串转换成十六进制值
     * @param bin String 我们看到的要转换成十六进制的字符串
     * @return
    */
    public static String bin2hex(String bin) {
        char[] digital = "0123456789ABCDEF".toCharArray();
        StringBuffer sb = new StringBuffer("");
        byte[] bs = bin.getBytes();
        int bit;
        for (int i = 0; i < bs.length; i++) {
            bit = (bs[i] & 0x0f0) >> 4;
            sb.append(digital[bit]);
            bit = bs[i] & 0x0f;
            sb.append(digital[bit]);
        }
        return sb.toString();
    }
}

SignUtil.java

package com.bijian.keystore;

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;

import org.apache.commons.codec.binary.Base64;

public class SignUtil {
    
    //#priKeyText
    private final static String priKeyText = "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";
    
    //#pubKeyText
    private final static String pubKeyText = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAoV5sWj7ekIPl04qmghtXGRCsBj2ysv0LOcRjceB6LZ4BlDNp/+RXWbUh2aHyVrDVFCqWWvgcp4TYNBNEJ+F66dFkovmeS4A3sE+w3gNG+QpMt/OjBFsHNdQLGvkrjIkeVxVI13VqzEF+RO8FUXG7qKuwPEAX5t4vBeD3TKJIZTL4sIS54Cjq1lSqGxPHMgNuSb9hWYMb9Tc1We88hmjutGuPV/zWgNqaHuTgfc1wX7GvJHx5dG/rDEDHd/Lla7QiKrNigAVuhBk06Hs5OeYvoR4O56jC7pu17cPM/09X6RLSoLJygDaYe3qkR1R5o1A6R4ncdwYkwAK8NOzFSKtS4QIDAQAB";
    
    private final static String CHARACTER_ENCODING_UTF_8 = "UTF-8";
    
    public static void main(String[] args) {
        
        String signString = "bijian 您好!";
        try {
            // 加签
            String localSignature = SignUtil.sign(priKeyText.getBytes(CHARACTER_ENCODING_UTF_8), signString);
            System.out.println(localSignature);
            //验签
            boolean verifyResult = SignUtil.verify(pubKeyText.getBytes(CHARACTER_ENCODING_UTF_8), signString, localSignature);
            System.out.println("verifyResult:" + verifyResult);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    /**
     * RSA私钥加签
     * @param priKeyText经过base64处理后的私钥
     * @param plainText明文内容
     * @return 十六进制的签名字符串
     * @throws Exception 
     */
    public static String sign(byte[] priKeyText, String plainText) throws Exception {
        try {
            PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64.decodeBase64(priKeyText));
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey prikey = keyf.generatePrivate(priPKCS8);

            // 用私钥对信息生成数字签名
            java.security.Signature signet = java.security.Signature.getInstance("SHA256withRSA");
            signet.initSign(prikey);
            signet.update(plainText.getBytes("UTF-8"));
            return DigestUtil.byte2hex(signet.sign());
        } catch (Exception e) {
            throw e; 
        }
    }
    
    /**
     * 公钥验签
     * @param pubKeyText经过base64处理后的公钥
     * @param plainText明文内容
     * @param signText十六进制的签名字符串
     * @return 验签结果 true验证一致 false验证不一致
     */
    public static boolean verify(byte[] pubKeyText, String plainText, String signText) {
        try {
            // 解密由base64编码的公钥,并构造X509EncodedKeySpec对象
            java.security.spec.X509EncodedKeySpec bobPubKeySpec = new java.security.spec.X509EncodedKeySpec(
                    Base64.decodeBase64(pubKeyText));
            // RSA算法
            java.security.KeyFactory keyFactory = java.security.KeyFactory.getInstance("RSA");
            // 取公钥匙对象
            java.security.PublicKey pubKey = keyFactory.generatePublic(bobPubKeySpec);
            // 十六进制数字签名转为字节
            byte[] signed = DigestUtil.hex2byte(signText.getBytes("UTF-8"));
            java.security.Signature signatureChecker = java.security.Signature.getInstance("SHA256withRSA");
            signatureChecker.initVerify(pubKey);
            signatureChecker.update(plainText.getBytes("UTF-8"));
            // 验证签名是否正常
            return signatureChecker.verify(signed);
        } catch (Throwable e) {
            return false;
        }
    }
}

运行结果如下，验签通过。

2.将F:\Key下生成公私钥验证加解密

将F:\Key下的testPub.key、testPri.key拷贝至工程中

运行如下代码

package com.bijian.keystore;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.security.Key;

import javax.crypto.Cipher;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class RSAUtil2 {
    
    /** 指定加密算法为RSA */
    private static final String ALGORITHM = "RSA";
    /** 指定公钥存放文件 */
    private static String PUBLIC_KEY_FILE = "testPub.key";
    /** 指定私钥存放文件 */
    private static String PRIVATE_KEY_FILE = "testPri.key";

    public static void main(String[] args) throws Exception {
        
        String source = "深圳，你好！";// 要加密的字符串
        System.out.println("准备用公钥加密的字符串为：" + source);
        
        String cryptograph = encrypt(source);// 生成的密文
        System.out.print("用公钥加密后的结果为:" + cryptograph);
        System.out.println();
       
        String target = decrypt(cryptograph);// 解密密文
        System.out.println("用私钥解密后的字符串为：" + target);
        System.out.println();   
    }
    
    /**
     * 加密方法
     * @param source 源数据
     * @return
     * @throws Exception
     */
    public static String encrypt(String source) throws Exception {
        
        Key publicKey = getKey(PUBLIC_KEY_FILE);

        /** 得到Cipher对象来实现对源数据的RSA加密 */
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] b = source.getBytes();
        /** 执行加密操作 */
        byte[] b1 = cipher.doFinal(b);
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(b1);
    }

    /**
     * 解密算法
     * @param cryptograph    密文
     * @return
     * @throws Exception
     */
    public static String decrypt(String cryptograph) throws Exception {
        
        Key privateKey = getKey(PRIVATE_KEY_FILE);

        /** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] b1 = decoder.decodeBuffer(cryptograph);

        /** 执行解密操作 */
        byte[] b = cipher.doFinal(b1);
        return new String(b);
    }
    
    private static Key getKey(String fileName) throws Exception, IOException {
        Key key;
        ObjectInputStream ois = null;
        try {
            /** 将文件中的私钥对象读出 */
            ois = new ObjectInputStream(new FileInputStream(fileName));
            key = (Key) ois.readObject();
        } catch (Exception e) {
            throw e;
        } finally {
            ois.close();
        }
        return key;
    }
}

运行结果：