AES＆＃x2B; RSA加密提供垃圾字符

Question

我正在尝试使用AES和RSA对XML文件进行加密，但解密后获得一些垃圾字符。

package com.example.demo.junk;


import org.apache.tomcat.util.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.time.Duration;
import java.time.Instant;

public class EncryptionPOC {

    private static IvParameterSpec getIv() {
        SecureRandom srandom = new SecureRandom();
        byte[] iv = new byte[128 / 8];
        srandom.nextBytes(iv);
        IvParameterSpec ivspec = new IvParameterSpec(iv);
        //Save it.
        try (FileOutputStream fos = new FileOutputStream("iv.file")) {
            fos.write(iv);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return ivspec;
    }

    private static SecretKey getSecretKey(String algorithm) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance(algorithm);
            kgen.init(128);
            return kgen.generateKey();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    private static PrivateKey loadPrivateKey() {
        try {
            byte[] bytes = Files.readAllBytes(Paths.get("private.key"));
            PKCS8EncodedKeySpec ks = new PKCS8EncodedKeySpec(bytes);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            PrivateKey pvt = kf.generatePrivate(ks);
            return pvt;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private static KeyPair getKeyPair(String algorithm) {
        try {
            KeyPairGenerator kpg = KeyPairGenerator.getInstance(algorithm);
            kpg.initialize(2048);
            KeyPair keyPair = kpg.generateKeyPair();
            return keyPair;
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    private static void writeContent(IvParameterSpec ivspec, PrivateKey privateKey, SecretKey secretKey) {

        try {
            FileOutputStream out = new FileOutputStream("Manifest-Encrypted.enc");
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            byte[] b = cipher.doFinal(secretKey.getEncoded());
            out.write(b);

            Cipher ci = Cipher.getInstance("AES/CBC/ISO10126Padding");
            ci.init(Cipher.ENCRYPT_MODE, secretKey, ivspec);
            try (FileInputStream in = new FileInputStream("Manifest1.xml")) {
                processFileForAes(ci, in, out);
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private static void readContent() {

        try {
            byte[] bytes = Files.readAllBytes(Paths.get("public.pub"));
            X509EncodedKeySpec ks = new X509EncodedKeySpec(bytes);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            PublicKey pub = kf.generatePublic(ks);

            FileInputStream in = new FileInputStream("Manifest-Encrypted.enc");
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            cipher.init(Cipher.DECRYPT_MODE, pub);
            byte[] b = new byte[256];
            in.read(b);
            byte[] keyb = cipher.doFinal(b);
            SecretKeySpec skey = new SecretKeySpec(keyb, "AES");

            byte[] iv = new byte[128 / 8];
            FileInputStream fis = new FileInputStream("iv.file");
            fis.read(iv);
            IvParameterSpec ivspec = new IvParameterSpec(iv);

            Cipher ci = Cipher.getInstance("AES/CBC/ISO10126Padding");
            ci.init(Cipher.DECRYPT_MODE, skey, ivspec);
            try (FileOutputStream out = new FileOutputStream("Manifest2.xml")) {
                processFile(ci, in, out);
                readFile("Manifest2.xml");
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private static void readFile(String fileName) throws IOException {
        try(FileInputStream out = new FileInputStream(fileName)) {
            int i;

            while ((i = out.read()) != -1) {
                System.out.print((char) i);
            }
            System.out.println();
        }
    }


    //  ////////////////////////////////////////////////////////////////////////////////////////
    private static void saveKeypair(KeyPair keyPair) {
        try (FileOutputStream out = new FileOutputStream("private.key")) {
            out.write(keyPair.getPrivate().getEncoded());
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }

        try (FileOutputStream out = new FileOutputStream("public.pub")) {
            out.write(keyPair.getPublic().getEncoded());
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }


    public static void RSAEncryption(PrivateKey privateKey) {

        try {
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);

            try (FileOutputStream out = new FileOutputStream("Doc-enc.des");
                 FileInputStream in = new FileInputStream("File1.deb")) {
                processFile(cipher, in, out);
            }
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    private static void processFile(Cipher ci, InputStream in, OutputStream out)
            throws javax.crypto.IllegalBlockSizeException,
            javax.crypto.BadPaddingException,
            java.io.IOException {
        byte[] ibuf = new byte[1024];
        int len;
        while ((len = in.read(ibuf)) != -1) {
            byte[] obuf = ci.update(ibuf, 0, len);
            if (obuf != null)
            {
                out.write(obuf);
            }
        }
        byte[] obuf = ci.doFinal();
        if (obuf != null) out.write(obuf);
    }


    static private void processFileForAes(Cipher ci, InputStream in, OutputStream out)
            throws javax.crypto.IllegalBlockSizeException,
            javax.crypto.BadPaddingException,
            java.io.IOException {
        byte[] ibuf = new byte[1024];
        int len;
        while ((len = in.read(ibuf)) != -1) {
            byte[] obuf = ci.update(ibuf, 0, len);
            if (obuf != null) out.write(obuf);
        }
        byte[] obuf = ci.doFinal();
        if (obuf != null) out.write(obuf);
    }

    public static void main(String[] args) {
//      Instant in1 = Instant.now();
//      KeyPair keyPair = getKeyPair("RSA");
//      saveKeypair(keyPair);
//      RSAEncryption(keyPair.getPrivate());
//      Instant in2 = Instant.now();
//
//      Duration duration = Duration.between(in1, in2);
//      System.out.println(duration.toMillis());

        //KeyPair keyPair = getKeyPair("RSA");
        //saveKeypair(keyPair);
//        Instant in1 = Instant.now();
//        SecretKey secretKey = getSecretKey("AES");
//        IvParameterSpec ivs = getIv();
//        PrivateKey privateKey = loadPrivateKey();
//        writeContent(ivs, privateKey, secretKey);
//        Instant in2 = Instant.now();
        readContent();
        //Duration duration = Duration.between(in1, in2);
        //System.out.println(duration.toMillis());

    }

}

输出：

＃y```

** 这个问题的根本原因？

Answer 1

主要问题是，当您创建密文时，您似乎将IV写入单独的文件，并假设将其写入文件时将其写入文件的前面。

此外，即使您使用流API从正确的位置获取内容字节，也应该知道Java inputStream.Read（）可能不会读取字节的缓冲区值。相反，您应该使用 inputStream＃readnbytes（int） 也获得了更多简洁的代码。

我还强烈建议您适当处理您的例外情况，并使用尝试 -with-resources。