[英]RSA encrypt with OpenSSL in Qt/C++ and decrypt in Java: Bad Padding Exception
I am trying out a sample program where I am encrypting a string with RSA public key in C++ Qt Framework (using statically linked OpenSSL C++ library), and decrypting the same ciphertext using javax.crypto library. I am trying out a sample program where I am encrypting a string with RSA public key in C++ Qt Framework (using statically linked OpenSSL C++ library), and decrypting the same ciphertext using javax.crypto library. I am sending this ciphertext through a socket connection using a free port on my PC to the localhost.
我正在使用我 PC 上的空闲端口通过套接字连接将这个密文发送到本地主机。
The following are the codes:以下是代码:
My Qt/C++ code:我的 Qt/C++ 代码:
main.cpp:主.cpp:
#include "cipher.h"
#include "assert.h"
#include "string.h"
#include <QApplication>
#include <QTcpSocket>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Cipher *cipher=new Cipher();
QTcpSocket *qts=new QTcpSocket();
qts->connectToHost("localhost",11111);
QByteArray message, enc_key,enc_message;
message="Elephant";
enc_message=cipher->encryptRSA(cipher->getPublicKey("publickey.pem"),message);
qDebug()<<message;
qDebug()<<enc_message;
if(qts->waitForConnected(300)){
qts->write(QString::fromStdString(enc_message.toStdString()).toUtf8().constData());
qts->write("\n");
qts->flush();
}
return a.exec();
}
For the encryptRSA function I used the example from VoidRealms' tutorial.对于 encryptRSA function,我使用了 VoidRealms 教程中的示例。 Here is the GitHub link: https://github.com/voidrealms/Qt-154
这是 GitHub 链接: https://github.com/voidrealms/Qt-154
From the above link I used cipher.h
and cipher.cpp
without any changes.从上面的链接中,我使用
cipher.h
和cipher.cpp
没有任何更改。
Java code: Java代码:
package servertest;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import org.apache.commons.io.FileUtils;
public class ServerTest {
static int port=11111;
static ServerSocket ss;
static Socket s;
public static void main(String[] args) {
System.out.println("Server Started!");
try {
ss = new ServerSocket(port);
s=ss.accept();
InputStreamReader isr = new InputStreamReader(new BufferedInputStream(s.getInputStream()));
BufferedReader br = new BufferedReader(isr);
String str=br.readLine();
System.out.println("Received: "+str);
byte[] encrypted = str.getBytes("UTF-8");
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
PrivateKey privateKey = loadPrivateKey();
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] decrypted = cipher.doFinal(encrypted);
System.out.println("Decrypted: "+new String(decrypted));
} catch (IOException ex) {
Logger.getLogger(ServerTest.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidKeyException ex) {
Logger.getLogger(ServerTest.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(ServerTest.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchPaddingException ex) {
Logger.getLogger(ServerTest.class.getName()).log(Level.SEVERE, null, ex);
} catch (Exception ex) {
Logger.getLogger(ServerTest.class.getName()).log(Level.SEVERE, null, ex);
}
}
public static PrivateKey loadPrivateKey() throws Exception {
String privateKeyPEM = FileUtils.readFileToString(new File("privatekey-pkcs8.pem"), StandardCharsets.UTF_8);
// strip off header, footer, newlines, whitespaces
privateKeyPEM = privateKeyPEM
.replace("-----BEGIN PRIVATE KEY-----", "")
.replace("-----END PRIVATE KEY-----", "")
.replace("-----BEGIN RSA PRIVATE KEY-----", "")
.replace("-----END RSA PRIVATE KEY-----", "")
.replaceAll("\\s", "");
//System.out.println(privateKeyPEM);
// decode to get the binary DER representation
byte[] privateKeyDER = Base64.getDecoder().decode(privateKeyPEM.getBytes("UTF-8"));
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(new PKCS8EncodedKeySpec(privateKeyDER));
return privateKey;
}
}
Also, I generated these keys using standard OpenSSL commands.此外,我使用标准 OpenSSL 命令生成了这些密钥。 I tried using different keys with different bit lengths but I get the same error.
我尝试使用具有不同位长度的不同密钥,但我得到了同样的错误。 I have converted the
privatekey.pem
to PKCS8 ( privatekey-pkcs8.pem
).我已将
privatekey.pem
转换为 PKCS8 ( privatekey-pkcs8.pem
)。 For generating and using the keys, I followed the link below:为了生成和使用密钥,我点击了下面的链接:
https://adangel.org/2016/08/29/openssl-rsa-java/ https://adangel.org/2016/08/29/openssl-rsa-java/
THE PROBLEM:问题:
I am getting javax.crypto.BadPaddingException: Decryption error
in Java.我收到
javax.crypto.BadPaddingException: Decryption error
。 What am I doing wrong?我究竟做错了什么?
THINGS I ALREADY TRIED我已经尝试过的事情
Please help me with this one.请帮我解决这个问题。
Okay, I SOLVED this problem, within 20 minutes after posting, by converting the ciphertext to Base64 and passing it through the socket and, of course, on the receiving side, I need to decode it back to bytes.好的,我在发布后的 20 分钟内解决了这个问题,方法是将密文转换为 Base64 并通过套接字传递,当然,在接收端,我需要将其解码回字节。
Previously when I tried this, I forgot to decode the Base64 text back to bytes.以前当我尝试这个时,我忘记将 Base64 文本解码回字节。 Sorry if I wasted somebody's time.
对不起,如果我浪费了别人的时间。
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