Angular+Ionic+RSA实现后端加密前端解密功能

因业务需要，需要给android应用安装证书，通过读取证书文件内容实现某些功能的控制；
流程：后台通过publicKey对指定内容的文件进行加密，生成文件共客户下载，客户下载后选择该证书文件读取到应用中；
后台加密代码：

package com.zl.unit.printunit;

import org.springframework.util.Base64Utils;

import java.io.ByteArrayOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;

/** */
/**
 * <p>
 * RSA公钥/私钥/签名工具包
 * </p>
 * <p>
 * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
 * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
 * </p>
 *
 * @author zhagnlei
 * @date 2019-4-29
 * @version 1.0
 */
public class RSAUtils {

    /** */
    /**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /** */
    /**
     * 签名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    /** */
    /**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /** */
    /**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    /** */
    /**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;

    /** */
    /**
     * RSA最大解密密文大小
     */
    private static final int MAX_DECRYPT_BLOCK = 128;


    private static final String PRIVATE_KEY_CODE = "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";

    private static final String PUBLIC_KEY_CODE = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDiMPz4qbXd9we8q4gnaGg3NaeH1Vbj9JA7odkBDDKCX5RoJotSPLX5n/6dWh3imUVmc6HNMo8oBOhki/W7+1KMyOUqI+h/uQDa35EvgrUSPwyc0QZszCyakk0uXtGqLdQz/IgrsywXfIzNL5sQ2679xinch4efgaikApmXYhSDywIDAQAB";

    /** */
    /**
     * <p>
     * 生成密钥对(公钥和私钥)
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    /** */
    /**
     * <p>
     * 用私钥对信息生成数字签名
     * </p>
     *
     * @param data       已加密数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64Utils.decodeFromString(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(privateK);
        signature.update(data);
        return Base64Utils.encodeToString(signature.sign());
    }

    /** */
    /**
     * <p>
     * 校验数字签名
     * </p>
     *
     * @param data      已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @param sign      数字签名
     * @return
     * @throws Exception
     */
    public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
        byte[] keyBytes = Base64Utils.decodeFromString(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicK = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(publicK);
        signature.update(data);
        return signature.verify(Base64Utils.decodeFromString(sign));
    }

    /** */
    /**
     * <P>
     * 私钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param privateKey    私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception {
        byte[] keyBytes = Base64Utils.decodeFromString(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /** */
    /**
     * <p>
     * 公钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param publicKey     公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception {
        byte[] keyBytes = Base64Utils.decodeFromString(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /** */
    /**
     * <p>
     * 公钥加密
     * </p>
     *
     * @param data      源数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
        byte[] keyBytes = Base64Utils.decodeFromString(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /** */
    /**
     * <p>
     * 私钥加密
     * </p>
     *
     * @param data       源数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64Utils.decodeFromString(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /** */
    /**
     * <p>
     * 获取私钥
     * </p>
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return Base64Utils.encodeToString(key.getEncoded());
    }

    /** */
    /**
     * <p>
     * 获取公钥
     * </p>
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return Base64Utils.encodeToString(key.getEncoded());
    }

    /**
     * java端公钥加密
     */
    public static String encryptedDataOnJava(String data, String PUBLICKEY) {
        try {
            data = Base64Utils.encodeToString(encryptByPublicKey(data.getBytes("UTF-8"), PUBLICKEY));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return data;
    }

    /**
     * java端私钥解密
     */
    public static String decryptDataOnJava(String data, String PRIVATEKEY) {
        String temp = "";
        try {
            byte[] rs = Base64Utils.decodeFromString(data);
            temp = new String(RSAUtils.decryptByPrivateKey(rs, PRIVATEKEY), "UTF-8");

        } catch (Exception e) {
            e.printStackTrace();
        }
        return temp;
    }

    public static void main(String[] args) {
        String data = "hello";
        String s = encryptedDataOnJava(data, PUBLIC_KEY_CODE);
        System.out.println(s);

    }

    /** 解密 */
    static void doc() {
        String data = "hAvU3rwHjyl+qf9lx+yo4//hvVWtjxyvQQPmUAa7RbjBJGjdLALiaXwWn3aHqbfajoCJKE7zQDDpAkGtisd9M9hzvboGbZVJ++5vFDxrGMVk5nEd8JR/zZY361gihSLoY3OrBpAOWkWs1f0JD8oe5XADZcH0nM85/K831Iwa6zw=";
        String s = decryptDataOnJava(data, PRIVATE_KEY_CODE);
        System.out.println(s);
    }

}