Spring boot RSA 文件加密解密

github项目地址 rsa_demo

测试

加密D:/hello/test.pdf 文件，生成加密后的文件 testNeedDecode.pdf

对testNeedDecode.pdf 文件进行解密，生成testFinal.pdf 文件

package com.lick.controller;

import java.util.Map;

import static com.lick.util.RSAUtils.*;

public class RSATest {
    public static void main(String[] args) throws Exception {
        Map<String, Object> initKey = initKey();
        String publicKeyStr = getPublicKeyStr(initKey);
        String privateKeyStr = getPrivateKeyStr(initKey);
        encryptFile("D:/hello/test.pdf","D:/hello/testNeedDecode.pdf",publicKeyStr);
        decryptFile("D:/hello/testNeedDecode.pdf","D:/hello/testFinal.pdf",privateKeyStr);

    }
}

添加依赖

<!-- 替换sun.misc.BASE64Encoder -->
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.10</version>
        </dependency>

RSAUtils.java

package com.lick.util;

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

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import java.io.*;
import java.security.*;
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;

public class RSAUtils {

    public static final String KEY_ALGORITHM = "RSA";
    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";
    public static final String SIGNATURE_ALGORITHM="MD5withRSA";
    /**
     * 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;

    public static Map<String, Object> initKey() 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;
    }
    //获得公钥字符串
    public static String getPublicKeyStr(Map<String, Object> keyMap) throws Exception {
        //获得map中的公钥对象 转为key对象
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        //编码返回字符串
        return encryptBASE64(key.getEncoded());
    }

    //获得私钥字符串
    public static String getPrivateKeyStr(Map<String, Object> keyMap) throws Exception {
        //获得map中的私钥对象 转为key对象
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        //编码返回字符串
        return encryptBASE64(key.getEncoded());
    }

    //获取公钥
    public static PublicKey getPublicKey(String key) throws Exception {
        byte[] keyBytes;
        // keyBytes = (new BASE64Decoder()).decodeBuffer(key);
        keyBytes = Base64.decodeBase64(key);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicKey = keyFactory.generatePublic(keySpec);
        return publicKey;
    }

    //获取私钥
    public static PrivateKey getPrivateKey(String key) throws Exception {
        byte[] keyBytes;
        //  keyBytes = (new BASE64Decoder()).decodeBuffer(key);
        keyBytes = Base64.decodeBase64(key);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
        return privateKey;
    }

    //解码返回byte
    public static byte[] decryptBASE64(String key) throws Exception {
        // return (new BASE64Decoder()).decodeBuffer(key);
        return Base64.decodeBase64(key);
    }

    //编码返回字符串
    public static String encryptBASE64(byte[] key) throws Exception {
        // return (new BASE64Encoder()).encodeBuffer(key);
        return Base64.encodeBase64String(key);
    }

    //***************************签名和验证*******************************
    public static byte[] sign(byte[] data,String privateKeyStr) throws Exception{
        PrivateKey priK = getPrivateKey(privateKeyStr);
        Signature sig = Signature.getInstance(SIGNATURE_ALGORITHM);
        sig.initSign(priK);
        sig.update(data);
        return sig.sign();
    }

    public static boolean verify(byte[] data,byte[] sign,String publicKeyStr) throws Exception{
        PublicKey pubK = getPublicKey(publicKeyStr);
        Signature sig = Signature.getInstance(SIGNATURE_ALGORITHM);
        sig.initVerify(pubK);
        sig.update(data);
        return sig.verify(sign);
    }

    //************************加密解密**************************
    public static byte[] encrypt(byte[] plainText,String publicKeyStr)throws Exception{
        PublicKey publicKey = getPublicKey(publicKeyStr);
        Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        int inputLen = plainText.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        int i = 0;
        byte[] cache;
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(plainText, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(plainText, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptText = out.toByteArray();
        out.close();
        return encryptText;
    }

    public static byte[] decrypt(byte[] encryptText,String privateKeyStr)throws Exception{
        PrivateKey privateKey = getPrivateKey(privateKeyStr);
        Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        int inputLen = encryptText.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(encryptText, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptText, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] plainText = out.toByteArray();
        out.close();
        return plainText;
    }
    //************************加密文件**************************
    public static void encryptFile(String inputPath, String outputPath, String publicKeyStr) throws Exception {
        try {
            KeyGenerator keygen = KeyGenerator.getInstance("AES");
            SecureRandom random = new SecureRandom();
            keygen.init(random);
            SecretKey key = keygen.generateKey();
            PublicKey publicKey = getPublicKey(publicKeyStr);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.WRAP_MODE, publicKey);
            byte[] wrappedKey = cipher.wrap(key);
            DataOutputStream out = new DataOutputStream(new FileOutputStream(outputPath));
            out.writeInt(wrappedKey.length);
            out.write(wrappedKey);
            InputStream in = new FileInputStream(inputPath);
            cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            crypt(in, out, cipher);
            in.close();
            out.close();
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //************************解密文件**************************
    public static void decryptFile(String inputPath, String outputPath, String privateKeyStr) throws Exception {
        try {
            DataInputStream in = new DataInputStream(new FileInputStream(inputPath));
            int length = in.readInt();
            byte[] wrappedKey = new byte[length];
            in.read(wrappedKey, 0, length);
            PrivateKey privateKey = getPrivateKey(privateKeyStr);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.UNWRAP_MODE, privateKey);
            Key key = cipher.unwrap(wrappedKey, "AES", Cipher.SECRET_KEY);

            OutputStream out = new FileOutputStream(outputPath);
            cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, key);

            crypt(in, out, cipher);
            in.close();
            out.close();
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //对数据分段加密解密
    public static void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException, GeneralSecurityException {
        int blockSize = cipher.getBlockSize();
        int outputSize = cipher.getOutputSize(blockSize);
        byte[] inBytes = new byte[blockSize];
        byte[] outBytes = new byte[outputSize];

        int inLength = 0;
        boolean next = true;
        while (next) {
            inLength = in.read(inBytes);
            if (inLength == blockSize) {
                int outLength = cipher.update(inBytes, 0, blockSize, outBytes);
                out.write(outBytes, 0, outLength);
            } else {
                next = false;
            }
        }
        if (inLength > 0) {
            outBytes = cipher.doFinal(inBytes, 0, inLength);
        } else {
            outBytes = cipher.doFinal();
        }
        out.write(outBytes);
    }

}