运用 DRM 对流媒体文件加密

以前用 C++ 做过的 DRM 项目，现抽取出其中核心的代码, 演示一下如何借助 DRM 对流媒体文件进行保护。虽然微软的 DRM 技术被破解了, 但那是以用户通过认证并下载证书为前提的。由是观之, 运用 DRM 对流媒体文件施以保护仍有一定意义，这毕竟比什么都不做要强嘛!/* drm.h*/#ifndef __DRM_H__#define __DRM_H__
#include #import "wmrmobjs.dll"
class DRMObject {public: DRMObject(char* inFile, char* outFile, char* licenseURL, char* corpName); bool Encrypt();
public: std::string key; std::string seed; std::string keyID; std::string contentID; std::string publicKey; std::string privateKey;
private: std::string _inFile; std::string _outFile; std::string _corpName; std::string _licenseURL;};
#endif// drm.cxx#include "drm.h"#include #include
DRMObject::DRMObject(char* inFile, char* outFile, char* licenseURL, char* corpName){ _inFile = inFile; _outFile = outFile; _corpName = corpName; _licenseURL = licenseURL;}
bool DRMObject::Encrypt() { try { HRESULT hr;
// Initialize the COM library on the current thread hr = CoInitialize(NULL); if (FAILED(hr)) _com_issue_error(hr);
WMRMOBJSLib::IWMRMKeysPtr keysObj("Wmrmobjs.WMRMKeys"); WMRMOBJSLib::IWMRMHeaderPtr headerObj("Wmrmobjs.WMRMHeader"); WMRMOBJSLib::IWMRMProtectPtr protectObj("Wmrmobjs.WMRMProtect");
// Generate keyID,seed,contentID keyID = keysObj->GenerateKeyID(); seed = keysObj->GenerateSeed(); contentID = keysObj->GenerateKeyID();
// Generate key keysObj->KeyID = keyID.c_str(); keysObj->Seed = seed.c_str(); key = keysObj->GenerateKey();
// Set protected header headerObj->KeyID = keyID.c_str(); headerObj->ContentID = contentID.c_str(); headerObj->LicenseAcqURL = _licenseURL.c_str(); headerObj->Attribute["Copyright"] = _corpName.c_str();
// verify the key headerObj->SetCheckSum(key.c_str());
//Generate public and private key _variant_t privKey, pubKey; VariantInit(&privKey); VariantInit(&pubKey); keysObj->GenerateSigningKeys(&privKey, &pubKey); headerObj->IndividualizedVersion = "2.2";
// Save private and public kyes privateKey = (_bstr_t)privKey; publicKey = (_bstr_t)pubKey;
// Sign key headerObj->Sign((_bstr_t)privKey);
// Set protect object _bstr_t header; header = headerObj->Header; protectObj->Header = header; protectObj->Key = key.c_str(); protectObj->V1KeyID = keyID.c_str();
// start encrypt protectObj->InputFile = _inFile.c_str(); protectObj->ProtectFile(_outFile.c_str()); } catch (const _com_error& e) { std::cerr << "COM Exception: " << e.ErrorMessage() << std::endl; if (e.ErrorInfo()) std::cerr << (char*)e.ErrorInfo() << std::endl; return false; }
CoUninitialize(); return true;}// drm_test.cxx#include "drm.h"#include using namespace std;
int main() { DRMObject* drmObj = new DRMObject("d:\\test.wma", "d:\\test2.wma", "http://localhost/test.asp", "test corp"); if (drmObj->Encrypt()) { cout << "KeyID: " <<>keyID <<>seed <<>key <<>contentID <<>publicKey <<>privateKey << endl; } delete drmObj;}