Java 在android中使用rsa解密时获取垃圾字符串

我使用netbeans编写了一个程序来加密一个字符串，它可以像java应用程序一样完美地运行。它解密文件中存储的文本。后来，我将文件传输到我的android程序，解密失败（android应用程序无法按预期工作）。它是在给垃圾字符串。即预加密字符串和后解密字符串不相同。代码如下，请查看并帮助我- RSABase.java

public class RSABase {

    public static byte[] hexToByte(String hex)  
    {  
        byte bts[] = new byte[hex.length() / 2];  
        for(int i = 0; i < bts.length; i++){  
            bts[i] = (byte)Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);  
        }  

        return bts;  
    }  

    public static String toHexString(byte bytes[])  
    {  
        StringBuffer retString = new StringBuffer();  
        for(int i = 0; i < bytes.length; i++)  
            retString.append(Integer.toHexString(256 + (bytes[i] & 0xff)).substring(1));  

        return retString.toString();  
    }  


}

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

import android.os.Environment;

/**
 *
 * @author Test01
 */
public class Decryptor extends RSABase {

    private PrivateKey key;
    private String text;

    public Decryptor(String text) {
        this.text = text;
        try {
            key=readPrivateKeyFromFile(Environment.getExternalStorageDirectory()+"/private.key");
        } catch (IOException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    private PublicKey readPublicKeyFromFile(String fileName) throws IOException {
        FileInputStream fis = null;
        ObjectInputStream ois = null;
        try {
            fis = new FileInputStream(new File(fileName));
            ois = new ObjectInputStream(fis);

            BigInteger modulus = (BigInteger) ois.readObject();
            BigInteger exponent = (BigInteger) ois.readObject();

            //Get Public Key  
            RSAPublicKeySpec rsaPublicKeySpec = new RSAPublicKeySpec(modulus, exponent);
            KeyFactory fact = KeyFactory.getInstance("RSA");
            PublicKey publicKey = fact.generatePublic(rsaPublicKeySpec);

            return publicKey;

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ois != null) {
                ois.close();
                if (fis != null) {
                    fis.close();
                }
            }
        }
        return null;
    }

    private PrivateKey readPrivateKeyFromFile(String fileName) throws IOException {
        FileInputStream fis = null;
        ObjectInputStream ois = null;
        try {
            fis = new FileInputStream(new File(fileName));
            ois = new ObjectInputStream(fis);

            BigInteger modulus = (BigInteger) ois.readObject();
            BigInteger exponent = (BigInteger) ois.readObject();

            //Get Private Key  
            RSAPrivateKeySpec rsaPrivateKeySpec = new RSAPrivateKeySpec(modulus, exponent);
            KeyFactory fact = KeyFactory.getInstance("RSA");
            key = fact.generatePrivate(rsaPrivateKeySpec);

            return key;

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ois != null) {
                ois.close();
                if (fis != null) {
                    fis.close();
                }
            }
        }
        return null;
    }

    public String decrypt(){
        byte[] decrypted=null;
        byte[] decryptable=hexToByte(text);
        String dec=null;
        try {
            Cipher cipher=Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, key);
            decrypted=cipher.doFinal(decryptable);
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (NoSuchPaddingException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InvalidKeyException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalBlockSizeException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (BadPaddingException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        }
        dec = new String(decrypted);
        return dec;
    }
}

Decryptor.java

public class RSABase {

    public static byte[] hexToByte(String hex)  
    {  
        byte bts[] = new byte[hex.length() / 2];  
        for(int i = 0; i < bts.length; i++){  
            bts[i] = (byte)Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);  
        }  

        return bts;  
    }  

    public static String toHexString(byte bytes[])  
    {  
        StringBuffer retString = new StringBuffer();  
        for(int i = 0; i < bytes.length; i++)  
            retString.append(Integer.toHexString(256 + (bytes[i] & 0xff)).substring(1));  

        return retString.toString();  
    }  


}

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

import android.os.Environment;

/**
 *
 * @author Test01
 */
public class Decryptor extends RSABase {

    private PrivateKey key;
    private String text;

    public Decryptor(String text) {
        this.text = text;
        try {
            key=readPrivateKeyFromFile(Environment.getExternalStorageDirectory()+"/private.key");
        } catch (IOException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    private PublicKey readPublicKeyFromFile(String fileName) throws IOException {
        FileInputStream fis = null;
        ObjectInputStream ois = null;
        try {
            fis = new FileInputStream(new File(fileName));
            ois = new ObjectInputStream(fis);

            BigInteger modulus = (BigInteger) ois.readObject();
            BigInteger exponent = (BigInteger) ois.readObject();

            //Get Public Key  
            RSAPublicKeySpec rsaPublicKeySpec = new RSAPublicKeySpec(modulus, exponent);
            KeyFactory fact = KeyFactory.getInstance("RSA");
            PublicKey publicKey = fact.generatePublic(rsaPublicKeySpec);

            return publicKey;

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ois != null) {
                ois.close();
                if (fis != null) {
                    fis.close();
                }
            }
        }
        return null;
    }

    private PrivateKey readPrivateKeyFromFile(String fileName) throws IOException {
        FileInputStream fis = null;
        ObjectInputStream ois = null;
        try {
            fis = new FileInputStream(new File(fileName));
            ois = new ObjectInputStream(fis);

            BigInteger modulus = (BigInteger) ois.readObject();
            BigInteger exponent = (BigInteger) ois.readObject();

            //Get Private Key  
            RSAPrivateKeySpec rsaPrivateKeySpec = new RSAPrivateKeySpec(modulus, exponent);
            KeyFactory fact = KeyFactory.getInstance("RSA");
            key = fact.generatePrivate(rsaPrivateKeySpec);

            return key;

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (ois != null) {
                ois.close();
                if (fis != null) {
                    fis.close();
                }
            }
        }
        return null;
    }

    public String decrypt(){
        byte[] decrypted=null;
        byte[] decryptable=hexToByte(text);
        String dec=null;
        try {
            Cipher cipher=Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, key);
            decrypted=cipher.doFinal(decryptable);
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (NoSuchPaddingException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InvalidKeyException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalBlockSizeException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        } catch (BadPaddingException ex) {
            Logger.getLogger(Decryptor.class.getName()).log(Level.SEVERE, null, ex);
        }
        dec = new String(decrypted);
        return dec;
    }
}

用于解密的代码：

Decryptor dec=new Decryptor(tokens[1]);//string loaded from file.
password=dec.decrypt();

它正在从文件中正确加载字符串。

---

感谢您的帮助。提前感谢。

您是在Java本地运行代码，还是将密钥和/或密文从Java SE传输到Android？请注意，我认为您已经很好地选择了标识符，但是类设计和异常处理还有一些需要改进的地方（例如，只使用静态方法扩展类是一种已知的反模式）。在se中创建了密钥并在android中使用。是的，我同意您仅使用静态方法扩展类。没有必要扩展这样的类。您可能需要检查Java SE和Android之间是否存在编码/解码问题。如果您可以创建这些关键点，它们可能是正常的（当然，除非您切换了它们）。例如，

dec=新字符串（已解密）未指定编码。我尝试了UTF-8，但仍然得到相同的垃圾。虽然原始字符串位于垃圾的末尾。