字串通過vc2008寫的DES加密，然后將加密后的字串通過JAVA代碼來解密，請各位幫忙，多謝
uj5u.com熱心網友回復：
主要注意不同語言型別對應關系，uj5u.com熱心網友回復：
這樣的需求完全可以實作，VC端使用OpenSSL、Crypto++庫，可以實作DES加密、解密，Java端使用SDK內置的方法可以進行加解密。DES演算法本身，與開發語言沒有關系，C++、Java都實作了DES演算法。
uj5u.com熱心網友回復：
多謝；如不使用OpenSSL，而只使用wincrypt，請問如何實作？uj5u.com熱心網友回復：
請大家幫忙，多謝uj5u.com熱心網友回復：
wincrypt，查MSDN。uj5u.com熱心網友回復：
僅供參考：#pragma comment(lib, "crypt32.lib")
#pragma comment(lib, "advapi32.lib")
#define _WIN32_WINNT 0x0400
#include <stdio.h>
#include <windows.h>
#include <wincrypt.h>
#define KEYLENGTH 0x00800000
void HandleError(char *s);
//--------------------------------------------------------------------
// These additional #define statements are required.
#define ENCRYPT_ALGORITHM CALG_RC4
#define ENCRYPT_BLOCK_SIZE 8
// Declare the function EncryptFile. The function definition
// follows main.
BOOL EncryptFile(
PCHAR szSource,
PCHAR szDestination,
PCHAR szPassword);
//--------------------------------------------------------------------
// Begin main.
void main(void) {
CHAR szSource[100];
CHAR szDestination[100];
CHAR szPassword[100];
printf("Encrypt a file. \n\n");
printf("Enter the name of the file to be encrypted: ");
scanf("%s",szSource);
printf("Enter the name of the output file: ");
scanf("%s",szDestination);
printf("Enter the password:");
scanf("%s",szPassword);
//--------------------------------------------------------------------
// Call EncryptFile to do the actual encryption.
if(EncryptFile(szSource, szDestination, szPassword)) {
printf("Encryption of the file %s was a success. \n", szSource);
printf("The encrypted data is in file %s.\n",szDestination);
} else {
HandleError("Error encrypting file!");
}
} // End of main
//--------------------------------------------------------------------
// Code for the function EncryptFile called by main.
static BOOL EncryptFile(
PCHAR szSource,
PCHAR szDestination,
PCHAR szPassword)
//--------------------------------------------------------------------
// Parameters passed are:
// szSource, the name of the input, a plaintext file.
// szDestination, the name of the output, an encrypted file to be
// created.
// szPassword, the password.
{
//--------------------------------------------------------------------
// Declare and initialize local variables.
FILE *hSource;
FILE *hDestination;
HCRYPTPROV hCryptProv;
HCRYPTKEY hKey;
HCRYPTHASH hHash;
PBYTE pbBuffer;
DWORD dwBlockLen;
DWORD dwBufferLen;
DWORD dwCount;
//--------------------------------------------------------------------
// Open source file.
if(hSource = fopen(szSource,"rb")) {
printf("The source plaintext file, %s, is open. \n", szSource);
} else {
HandleError("Error opening source plaintext file!");
}
//--------------------------------------------------------------------
// Open destination file.
if(hDestination = fopen(szDestination,"wb")) {
printf("Destination file %s is open. \n", szDestination);
} else {
HandleError("Error opening destination ciphertext file!");
}
//以下獲得一個CSP句柄
if(CryptAcquireContext(
&hCryptProv,
NULL, //NULL表示使用默認密鑰容器，默認密鑰容器名
//為用戶登陸名
NULL,
PROV_RSA_FULL,
0)) {
printf("A cryptographic provider has been acquired. \n");
} else {
if(CryptAcquireContext(
&hCryptProv,
NULL,
NULL,
PROV_RSA_FULL,
CRYPT_NEWKEYSET))//創建密鑰容器
{
//創建密鑰容器成功，并得到CSP句柄
printf("A new key container has been created.\n");
} else {
HandleError("Could not create a new key container.\n");
}
}
//--------------------------------------------------------------------
// 創建一個會話密鑰（session key）
// 會話密鑰也叫對稱密鑰，用于對稱加密演算法。
// （注: 一個Session是指從呼叫函式CryptAcquireContext到呼叫函式
// CryptReleaseContext 期間的階段。會話密鑰只能存在于一個會話程序）
//--------------------------------------------------------------------
// Create a hash object.
if(CryptCreateHash(
hCryptProv,
CALG_MD5,
0,
0,
&hHash)) {
printf("A hash object has been created. \n");
} else {
HandleError("Error during CryptCreateHash!\n");
}
//--------------------------------------------------------------------
// 用輸入的密碼產生一個散列
if(CryptHashData(
hHash,
(BYTE *)szPassword,
strlen(szPassword),
0)) {
printf("The password has been added to the hash. \n");
} else {
HandleError("Error during CryptHashData. \n");
}
//--------------------------------------------------------------------
// 通過散列生成會話密鑰
if(CryptDeriveKey(
hCryptProv,
ENCRYPT_ALGORITHM,
hHash,
KEYLENGTH,
&hKey)) {
printf("An encryption key is derived from the password hash. \n");
} else {
HandleError("Error during CryptDeriveKey!\n");
}
//--------------------------------------------------------------------
// Destroy the hash object.
CryptDestroyHash(hHash);
hHash = NULL;
//--------------------------------------------------------------------
// The session key is now ready.
//--------------------------------------------------------------------
// 因為加密演算法是按ENCRYPT_BLOCK_SIZE 大小的塊加密的，所以被加密的
// 資料長度必須是ENCRYPT_BLOCK_SIZE 的整數倍。下面計算一次加密的
// 資料長度。
dwBlockLen = 1000 - 1000 % ENCRYPT_BLOCK_SIZE;
//--------------------------------------------------------------------
// Determine the block size. If a block cipher is used,
// it must have room for an extra block.
if(ENCRYPT_BLOCK_SIZE > 1)
dwBufferLen = dwBlockLen + ENCRYPT_BLOCK_SIZE;
else
dwBufferLen = dwBlockLen;
//--------------------------------------------------------------------
// Allocate memory.
if(pbBuffer = (BYTE *)malloc(dwBufferLen)) {
printf("Memory has been allocated for the buffer. \n");
} else {
HandleError("Out of memory. \n");
}
//--------------------------------------------------------------------
// In a do loop, encrypt the source file and write to the destination file.
do {
//--------------------------------------------------------------------
// Read up to dwBlockLen bytes from the source file.
dwCount = fread(pbBuffer, 1, dwBlockLen, hSource);
if(ferror(hSource)) {
HandleError("Error reading plaintext!\n");
}
//--------------------------------------------------------------------
// 加密資料
if(!CryptEncrypt(
hKey, //密鑰
0, //如果資料同時進行散列和加密，這里傳入一個
//散列物件
feof(hSource), //如果是最后一個被加密的塊，輸入TRUE.如果不是輸.
//入FALSE這里通過判斷是否到檔案尾來決定是否為
//最后一塊。
0, //保留
pbBuffer, //輸入被加密資料，輸出加密后的資料
&dwCount, //輸入被加密資料實際長度，輸出加密后資料長度
dwBufferLen)) //pbBuffer的大小。
{
HandleError("Error during CryptEncrypt. \n");
}
//--------------------------------------------------------------------
// Write data to the destination file.
fwrite(pbBuffer, 1, dwCount, hDestination);
if(ferror(hDestination)) {
HandleError("Error writing ciphertext.");
}
} while(!feof(hSource));
//--------------------------------------------------------------------
// End the do loop when the last block of the source file has been
// read, encrypted, and written to the destination file.
//--------------------------------------------------------------------
// Close files.
if(hSource)
fclose(hSource);
if(hDestination)
fclose(hDestination);
//--------------------------------------------------------------------
// Free memory.
if(pbBuffer)
free(pbBuffer);
//--------------------------------------------------------------------
// Destroy session key.
if(hKey)
CryptDestroyKey(hKey);
//--------------------------------------------------------------------
// Destroy hash object.
if(hHash)
CryptDestroyHash(hHash);
//--------------------------------------------------------------------
// Release provider handle.
if(hCryptProv)
CryptReleaseContext(hCryptProv, 0);
return(TRUE);
} // End of Encryptfile
//--------------------------------------------------------------------
// This example uses the function HandleError, a simple error
// handling function, to print an error message to the standard error
// (stderr) file and exit the program.
// For most applications, replace this function with one
// that does more extensive error reporting.
void HandleError(char *s) {
fprintf(stderr,"An error occurred in running the program. \n");
fprintf(stderr,"%s\n",s);
fprintf(stderr, "Error number %x.\n", GetLastError());
fprintf(stderr, "Program terminating. \n");
exit(1);
} // End of HandleError
uj5u.com熱心網友回復：
你正常加密就是了java也正常解密即可
uj5u.com熱心網友回復：
]只說一個重要的問題，解決了這個就都好解決了，其他很多地方涉及java和C端通信的例子類似：
1.如何把java的float轉byte[]或反向轉換，類似的還有int->byte[] ...
2.C端傳上來的char*就對應java的byte[]
3.java端DES解密加密函式是有個byte[]引數入口的
4.總結，java和C端互動，涉及到緩沖和傳輸的問題，都通過byte[]中轉
uj5u.com熱心網友回復：
說的好，其實讀位元組應該算是C／C++程式員的基本功了
轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/119470.html
標籤：基礎類
下一篇：MFC讀取文本檔案資料遇到的情況