Encrypt/decrypt in c++ and java

Question

Hi,
I have a problem in encryt a file using RC2 in java and decrypt in c++.
I am using the bouncycastle.org as my RC2 provider in JCE.
Here is the code in c++
void CEScoreDlg::encrypt(BYTE *pData, unsigned long dwDataSize, unsigned long *dwOutSize)
     HCRYPTPROV hProv =0;
     HCRYPTKEY hKey = 0;
     HCRYPTHASH hHash = 0;
                     char *pword = "pass";
     try
          if(!CryptAcquireContext(&hProv, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
               throw CryptError("Error during CryptAcquireContext!\n");
          if(!CryptCreateHash(hProv, CALG_MD5, 0, 0, &hHash))
               throw CryptError("Error during CryptCreateHash!\n");
          DWORD dwPwdLength = strlen(pword);
          if(!CryptHashData(hHash, (BYTE*)pword, dwPwdLength, 0))
               throw CryptError("Error during CryptHashData!\n");
          if(!CryptDeriveKey(hProv, CALG_RC2, hHash, 0, &hKey))
               throw CryptError("Error during CryptDeriveKey!\n");
          if(!CryptEncrypt(hKey, 0, TRUE, 0, pData, &dwDataSize, dwDataSize + 2 + dwPwdLength))
               throw CryptError("Error during CryptEncrypt!\n");
          *dwOutSize = dwDataSize;
     catch(CryptError& e)
          CString errmsg;
          LPVOID lpMsgBuf;
          FormatMessage(
               FORMAT_MESSAGE_ALLOCATE_BUFFER |
               FORMAT_MESSAGE_FROM_SYSTEM |
               FORMAT_MESSAGE_IGNORE_INSERTS,
               NULL,
               GetLastError(),
               MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
               (LPTSTR) &lpMsgBuf,
               0,
               NULL
          // Free the buffer.
          errmsg.Format("%s%s", e.msg, (LPCTSTR)lpMsgBuf);
          LocalFree( lpMsgBuf );
          MessageBox(errmsg, "Encryption error!", MB_OK|MB_ICONSTOP);
     if(hHash != 0)
          CryptDestroyHash(hHash);
     if(hKey != 0)
          CryptDestroyKey(hKey);
     if(hProv != 0)
          CryptReleaseContext(hProv, 0);
}and here is my java code try to decrypt the file generated by the c++ code.
     public static void decrypt (String passphrase, byte [] data) throws Exception
   byte iv[] = {1,2,3,4,5,6,7,8};
   byte [] dataTemp;
    MessageDigest md = MessageDigest.getInstance("MD5");
    md.update(passphrase.getBytes());
    SecretKeySpec RC2Key = new SecretKeySpec (md.digest(), "RC2");
     Cipher cipher = Cipher.getInstance("RC2/CBC/PKCS5Padding");
    cipher.init(Cipher.DECRYPT_MODE, RC2Key, new RC2ParameterSpec(128,iv));
      CipherInputStream cis = new CipherInputStream (new FileInputStream("/test.ctm"), cipher);
    StringBuffer read=new StringBuffer();
    byte[] bytes=new byte[1];
    while(cis.read(bytes)!=-1){
      read.append(new String(bytes));
    cis.close();
    System.out.println("Got message From reading the file:");
    System.out.println(read.toString());And it does not seems to understand each other. I am a newbie in JCE and not familiar with c++ either.
Please help, thanks
Fred

Answer 1

And it does not seems to understand each other.
I am
a newbie in JCE and not familiar with c++ either. Based on this you did not write the code you have presented so you should get the author of the code to debug it and you should start reading! To help the guy you could asking where the C code gets it's IV from, why RSA is involved in the C code and where CBC and PKCS5Padding are specified in the C code!
You have a long road to drive but it will be worth it in the end!