项目中遇到一个问题，需要进行RSA解密。但是因为不想在SDK中集成OpenSSL的库，所以研究了下window下的wincrypt。
直接贴代码了，但需要说明的是：用openSSL公钥生成密文，wincrypt用私钥进行解密。明文长度可能超过RSA加密限制，会进行分段加密。
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unsigned char* pri_key = "-----BEGIN RSA PRIVATE KEY-----\n"
"MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAKs+AIwlbXsk3YNb\n"
"u1kWT8UHqlSku8s6job8S40Pxdmm199dvKJjZWxwxGE/6QpV5os70e4RhHdmXvzH\n"
"yhHqmvK2y1z8y556uxYPGHiIZIexlcbEDjWFetctESWtJNFzjd5rXyjTMzFmhVmJ\n"
"HYkW3tByAz5Pp46u+Pn0yFe/07jpAgMBAAECgYBj1YH8MtXhNVzveEuBZMCc3hsv\n"
"vdq+YSU3DV/+nXN7sQmp77xJ8CjxT80t5VS38dy2z+lUImJYOhamyNPGHkC2y84V\n"
"7i5+e6ScQve1gnwHqRKGBjtSCaYOqm9rTDECCTT1oMU26sfYznWlJqMrkJp1jWn7\n"
"aAwr+3FcX2XhD74ZAQJBAN34Y6fmHLRPv21MsdgGqUjKgyFvJfLUmtFFgb6sLEWc\n"
"k22J3BAFAcNCTLYHFZwMhL/nwaw9/7rIUJD+lcl6n3cCQQDFfrN14qKC3GJfoBZ8\n"
"k9S6F7Ss514DDPzIuenbafhoUjZDVcjLw9EmYZQjpfsQ3WdNICUKRrDHZay1Pz+s\n"
"YkKfAkB+OKfaquS5t/t/2LPsxuTuipIEqiKnMjSTOfYsidVnBEFlcZZc2awF76aV\n"
"f/PO1+OJCO2910ebXBtMSCi++GbDAkEAmc7zNPwsVH4OnyquWJdJNSUBMSd/sCCN\n"
"PkaMOrVtINHmMMq+dvMqEBoupRS/U4Ma0JYYQsiLJL+qof2AOWDNQQJAcquLGHLT\n"
"eGDDLluHo+kkIGwZi4aK/fDoylZ0NCEtYyMtShQ3JmllST9kmb9NJX2gMsejsirc\n"
"H6ObxqZPbka6UA==\n"
"-----END RSA PRIVATE KEY-----\n";
static BOOL rsa_init(HCRYPTPROV** hProv, HCRYPTKEY* hKey)
{
DWORD dwBufferLen = 0, cbKeyBlob = 0, cbSignature = 0, i;
LPBYTE pbBuffer = NULL, pbKeyBlob = NULL, pbSignature = NULL;
if (!CryptStringToBinaryA(pri_key, 0, CRYPT_STRING_BASE64HEADER, NULL, &dwBufferLen, NULL, NULL))
{
printf("Failed to convert BASE64 private key. Error 0x%.8X\n", GetLastError());
goto main_exit;
}
pbBuffer = (LPBYTE)LocalAlloc(0, dwBufferLen);
if (pbBuffer == NULL) {
goto main_exit;
}
if (!CryptStringToBinaryA(pri_key, 0, CRYPT_STRING_BASE64HEADER, pbBuffer, &dwBufferLen, NULL, NULL))
{
printf("Failed to convert BASE64 private key. Error 0x%.8X\n", GetLastError());
goto main_exit;
}
if (!CryptDecodeObjectEx(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, PKCS_RSA_PRIVATE_KEY, pbBuffer, dwBufferLen, 0, NULL, NULL, &cbKeyBlob))
{
printf("Failed to parse private key. Error 0x%.8X\n", GetLastError());
goto main_exit;
}
pbKeyBlob = (LPBYTE)LocalAlloc(0, cbKeyBlob);
if (pbKeyBlob == NULL) {
goto main_exit;
}
if (!CryptDecodeObjectEx(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, PKCS_RSA_PRIVATE_KEY, pbBuffer, dwBufferLen, 0, NULL, pbKeyBlob, &cbKeyBlob))
{
printf("Failed to parse private key. Error 0x%.8X\n", GetLastError());
goto main_exit;
}
if (!CryptAcquireContext(hProv, "BenTestKeyContainer", MS_ENHANCED_PROV, PROV_RSA_FULL, 0))
{
if (!CryptAcquireContext(hProv, "BenTestKeyContainer", MS_ENHANCED_PROV, PROV_RSA_FULL, CRYPT_NEWKEYSET))
{
printf("CryptAcquireContext failed with error 0x%.8X\n", GetLastError());
goto main_exit;
}
}
if (!CryptImportKey(*hProv, pbKeyBlob, cbKeyBlob, NULL, 0, hKey))
{
printf("CryptImportKey for private key failed with error 0x%.8X\n", GetLastError());
goto main_exit;
}
if (pbBuffer) LocalFree(pbBuffer);
if (pbKeyBlob) LocalFree(pbKeyBlob);
return TRUE;
main_exit:
if (pbBuffer) LocalFree(pbBuffer);
if (pbKeyBlob) LocalFree(pbKeyBlob);
return FALSE;
}
BOOL private_decrypt(const unsigned char* data, int data_len,
const unsigned char* pri_key, int key_len,
unsigned char** dst, int* dst_len)
{
HCRYPTPROV hProv = NULL;
HCRYPTKEY hKey = NULL;
BOOL ret = rsa_init(&hProv, &hKey);
if (!ret) {
return ret;
}
DWORD dwBlockLen,dwDataLen = 4;
if (!CryptGetKeyParam(hKey, KP_BLOCKLEN, (BYTE *)&dwBlockLen, &dwDataLen, 0))
{
return FALSE;
}
dwBlockLen /= 8;
unsigned char *temp = (unsigned char *)malloc((size_t)dwBlockLen + 1);
if (temp == NULL)
{
LocalFree(base64Out);
return FALSE;
}
for (int j = 0; j < base64OutLen; j += dwBlockLen){
unsigned char *p = base64Out + j;
int ilen = dwBlockLen;
char* pTemp = p + ilen - 1;
int itemp = 0;
while (p < pTemp){
itemp = *pTemp;
*pTemp = *p;
*p = itemp;
pTemp--;
p++;
}
}
unsigned char* outputData = (unsigned char*)malloc(data_len);
if (outputData == NULL) {
return FALSE;
}
memset(outputData, 0, data_len);
*dst = outputData;
*dst_len = data_len;
int blockSize = dwBlockLen;
int pos = 0;
while (pos < data_len) {
memset(temp, 0, (size_t)dwBlockLen + 1);
int size = min((int)dwBlockLen, data_len - pos);
memcpy(temp, base64Out + pos, size);
ret = CryptDecrypt(hKey, NULL, flag, 0, tempData, &size);
if (ret > 0) {
memcpy(outputData + pos, tempData, size);
pos += blockSize;
printf("%s\n", outputData);
}
else {
printf("CryptDecrypt error!,%d\n", GetLastError());
CryptDestroyKey(hKey);
CryptReleaseContext(hProv, 0);
return FALSE;
}
}
printf("outputData=%s\n", outputData);
CryptDestroyKey(hKey);
CryptReleaseContext(hProv, 0);
return TRUE;
}
int rsa_encrypt(const unsigned char* data, int data_len, unsigned char** dstData, int* dst_len)
{
BOOL ret = private_decrypt(data, data_len, pri_key, strlen(pri_key), dstData, dst_len);
return ret;
}
特别强调：因为OpenSSL加密后的密文与wincrypt的密文刚好反转了。所以OpenSSL生成的密文需要反转再送进去。
代码下载