wincrypt des 加密 8字节补齐 跨平台

原理：wincrypt des加密时，如果需要加密的buffer大小不是8字节倍数，它会在数据的末尾添加字节，这些字节的值等于缺少的字节数。

源码：

　　#include <openssl/des.h>
　　const BYTE IV[] = "12345678";
 1 DWORD DESEncrypt(WCHAR* data, char* password, BYTE* buffer, DWORD bufferLength)
 2 {
 3     DWORD dataLength = STD::my_wcslen(data) * 2;
 4 
 5     if (buffer == NULL || bufferLength < dataLength + 8 - (dataLength % 8) || strlen(password) < 8) return 0;
 6 #ifdef WIN32
 7     memcpy(buffer, (char*)data, dataLength);
 8     HCRYPTPROV hProv = NULL;
 9     HCRYPTKEY hSessionKey = NULL;
10     bool bResult = TRUE;
11     KeyBlob blob;
12     blob.header.bType = PLAINTEXTKEYBLOB;
13     blob.header.bVersion = CUR_BLOB_VERSION;
14     blob.header.reserved = 0;
15     blob.header.aiKeyAlg = CALG_DES;
16     blob.cbKeySize = 8;
17     memcpy(blob.rgbKeyData, password, 8);
18     bResult &= CryptAcquireContext(&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL, 0);
19     bResult &= CryptImportKey(hProv, (BYTE*)&blob, sizeof(blob), 0, 0, &hSessionKey);
20     bResult &= CryptSetKeyParam(hSessionKey, KP_IV, (BYTE*)IV, 0);
21     bResult &= CryptEncrypt(hSessionKey, NULL, TRUE, 0, (BYTE*)buffer, &dataLength, bufferLength);
22     bResult &= CryptDestroyKey(hSessionKey);
23     bResult &= CryptReleaseContext(hProv, 0);
24     return bResult ? dataLength : 0;
25 #else
26     DES_cblock key;
27     DES_key_schedule schedule;
28     DES_cblock iv;
29 
30     // 设置密钥
31     memcpy(key, password, 8);
32     DES_set_key_unchecked(&key, &schedule);
33 
34     // 设置初始化向量（IV）
35     memcpy(iv, IV, 8);
36 
37     //填充数据长度
38     size_t nPadded = (8 - (dataLength % 8))%8;
39     DWORD paddedDataLength = dataLength + nPadded;
40     void* p = reinterpret_cast<void*>(data)+ dataLength;
41     memset(p, nPadded, nPadded);
42 
43     // 加密数据
44     DES_ncbc_encrypt((BYTE*)data, buffer, paddedDataLength, &schedule, &iv, DES_ENCRYPT);
45 
46     return paddedDataLength;
47 #endif
48 }