Java 密钥库 证书 公钥 私钥

1.密钥库

密钥库keystore是存储一个或多个密钥条目的文件，每个密钥条目以一个别名标识，它包含密钥和证书相关信息。可以使用java自带工具keytool生成，也可以通过程序编码实现。

• 密钥库文件格式（实际上，扩展名并不重要），比较常用的是jks和pkcs12。

2.使用Java的keytool工具生成密钥库

keytool -genkeypair -alias fire -storetype PKCS12  -keyalg RSA -keystore fire.pkcs12 -storepass 13987664391 -validity 3650 -keysize 2048
您的名字与姓氏是什么?
  [Unknown]:  xu.dm
您的组织单位名称是什么?
  [Unknown]:  com.home
您的组织名称是什么?
  [Unknown]:  home
您所在的城市或区域名称是什么?
  [Unknown]:  km
您所在的省/市/自治区名称是什么?
  [Unknown]:  yn
该单位的双字母国家/地区代码是什么?
  [Unknown]:  cn
CN=xu.dm, OU=com.home, O=home, L=km, ST=yn, C=cn是否正确?
  [否]:  y

3.查看密钥库keystore证书BASE64信息

keytool -list -rfc -keystore fire.pkcs12 -storepass 13987664391

密钥库类型: PKCS12
密钥库提供方: SUN

您的密钥库包含 1 个条目

别名: fire
创建日期: 2021-1-25
条目类型: PrivateKeyEntry
证书链长度: 1
证书[1]:
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----


*******************************************
*******************************************

4.使用java代码生成密钥库

    public static void createKeyStoreFile() throws Exception {
        String filePath = "e:/myProgram/key/home.keystore";
        final int keySize = 2048;
        final String commonName = "xu.dm";
        final String organizationalUnit = "com.home";
        final String organization = "home";
        final String city = "km";
        final String state = "yn";
        final String country = "cn";
        final long validity = 3650; // 10 years
        final String alias = "home";
        final String keyPassword = "13987664391";
        // keytool工具
        CertAndKeyGen keyGen = new CertAndKeyGen("RSA", "SHA1WithRSA");
        // 通用信息
        X500Name x500Name = new X500Name(commonName, organizationalUnit, organization, city, state, country);
        // 根据密钥长度生成公钥和私钥
        keyGen.generate(keySize);

        PrivateKey privateKey = keyGen.getPrivateKey();

        // 证书
        X509Certificate certificate = keyGen.getSelfCertificate(x500Name, new Date(), (long) validity * 24 * 60 * 60);


        KeyStore keyStore = KeyStore.getInstance("PKCS12");
        keyStore.load(null,null);
        keyStore.setKeyEntry(alias,privateKey,keyPassword.toCharArray(),new Certificate[]{certificate});

        FileOutputStream outputStream = new FileOutputStream(filePath);
        keyStore.store(outputStream,keyPassword.toCharArray());

        outputStream.close();
        System.out.println("keyStore file created ...");
    }

5.从密钥库keystore里提取私钥和证书

    public static PrivateKey getPrivateKey() throws Exception {
        String storepass = "13987664391";
        String keyAlias = "honor";
        BASE64Encoder base64Encoder = new BASE64Encoder();
        KeyStore keystore = KeyStore.getInstance("PKCS12");
        keystore.load(KeyTools.class.getResourceAsStream("/key/home.pkcs12"), storepass.toCharArray());
        PrivateKey key = (PrivateKey) keystore.getKey(keyAlias, storepass.toCharArray());
        System.out.println(key.toString());
        String privateKeyStr = base64Encoder.encode(key.getEncoded());
        System.out.println();
        System.out.println("-----BEGIN PRIVATE KEY-----");
        System.out.println(privateKeyStr);
        System.out.println("-----END PRIVATE KEY-----");

        Certificate certificate = keystore.getCertificate(keyAlias);
        PublicKey publicKey = certificate.getPublicKey();
        System.out.println(publicKey);

        // 打印certificate的base64编码
        String certificateString = base64Encoder.encode(certificate.getEncoded());
        System.out.println();
        System.out.println("-----BEGIN CERTIFICATE-----");
        System.out.println(certificateString);
        System.out.println("-----END CERTIFICATE-----");

        return key;
    }

6.从证书中提取公钥BASE64编码字符串

    /**
     * 从CERTIFICATE文本中提取public key字符串
     * CERTIFICATE本质是文本以"-----BEGIN CERTIFICATE-----"
     * 并以"-----END CERTIFICATE-----"结束
     */
    public static String getPublicKeyFromCertificate() throws CertificateException {
        InputStream inputStream = KeyTools.class.getResourceAsStream("/key/home.PKCS12.cer");
        CertificateFactory ft = CertificateFactory.getInstance("X.509");
        X509Certificate certificate = (X509Certificate) ft.generateCertificate(inputStream);
        PublicKey publicKey = certificate.getPublicKey();
        BASE64Encoder b64 = new BASE64Encoder();
        String result = b64.encode(publicKey.getEncoded());
        System.out.println("-----BEGIN PUBLIC KEY-----");
        System.out.println(result);
        System.out.println("-----END PUBLIC KEY-----");
        return result;
    }

7.从公钥BASE64字符串生成PublicKey对象

    /**
     * 从public key字符串中创建PublicKey对象
     *
     * @param signingKey 不包括"-----BEGIN PUBLIC KEY-----"和"-----END PUBLIC KEY-----"
     */
    public static PublicKey getRsaPublicKey(String signingKey) {
        try {
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(new BASE64Decoder().decodeBuffer(signingKey));
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(keySpec);
            return publicKey;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

8.从密钥库keystore中提取密钥对，密钥对可以提取公钥和私钥对象

    /**
     * 根据Keystore生成密钥对
     */
    public static KeyPair getKeyPair() throws Exception {
        String storepass = "13987664391";
        String keyAlias = "honor";
        KeyStore keystore = KeyStore.getInstance("PKCS12");
        keystore.load(KeyTools.class.getResourceAsStream("/key/home.pkcs12"), storepass.toCharArray());

        RSAPrivateCrtKey key = (RSAPrivateCrtKey) keystore.getKey(keyAlias, storepass.toCharArray());
        RSAPublicKeySpec spec = new RSAPublicKeySpec(key.getModulus(), key.getPublicExponent());
        PublicKey publicKey = KeyFactory.getInstance("RSA").generatePublic(spec);
        return new KeyPair(publicKey, key);
    }