用C++程序实现输入信息用RAS加密和解密

以下是一个使用 C++ 实现 RSA 加密和解密的示例代码：

#include <iostream>
#include <string>
#include <vector>
#include <Windows.h>
#include <wincrypt.h>

#pragma comment(lib, "crypt32.lib")

using namespace std;

// 生成 RSA 公钥和私钥
bool GenerateRSAKeys(HCRYPTPROV hProv, HCRYPTKEY& hPublicKey, HCRYPTKEY& hPrivateKey)
{
    bool success = false;

    // 生成 RSA 密钥对
    if (CryptGenKey(hProv, AT_SIGNATURE, CRYPT_EXPORTABLE | 0x800000, &hPrivateKey))
    {
        DWORD dwPublicKeyLen = 0;

        // 获取 RSA 公钥大小
        if (CryptExportKey(hPrivateKey, 0, PUBLICKEYBLOB, 0, NULL, &dwPublicKeyLen))
        {
            BYTE* pPublicKeyBlob = new BYTE[dwPublicKeyLen];

            // 导出 RSA 公钥
            if (CryptExportKey(hPrivateKey, 0, PUBLICKEYBLOB, 0, pPublicKeyBlob, &dwPublicKeyLen))
            {
                // 导入 RSA 公钥
                if (CryptImportKey(hProv, pPublicKeyBlob, dwPublicKeyLen, 0, 0, &hPublicKey))
                {
                    success = true;
                }
            }

            delete[] pPublicKeyBlob;
        }
    }

    return success;
}

// RSA 加密
bool EncryptRSA(HCRYPTKEY hPublicKey, const BYTE* pData, DWORD dwDataLen, vector<BYTE>& encryptedData)
{
    bool success = false;

    DWORD dwBlockLen = 0;
    DWORD dwEncryptedLen = 0;

    // 获取 RSA 加密块大小
    if (CryptGetKeyParam(hPublicKey, KP_BLOCKLEN, (BYTE*)&dwBlockLen, &dwEncryptedLen, 0))
    {
        DWORD dwPadding = 0;

        // 计算 RSA 加密填充长度
        if (CryptGetKeyParam(hPublicKey, KP_PADDING, (BYTE*)&dwPadding, &dwEncryptedLen, 0))
        {
            DWORD dwBlockSize = (dwBlockLen + 7) / 8;
            DWORD dwBlockCount = (dwDataLen + dwBlockSize - 1) / dwBlockSize;

            encryptedData.resize(dwBlockCount * dwBlockSize);

            for (DWORD i = 0; i < dwBlockCount; i++)
            {
                DWORD dwBlockDataLen = min(dwDataLen - i * dwBlockSize, dwBlockSize);
                DWORD dwEncryptedDataLen = encryptedData.size() - i * dwBlockSize;

                if (!CryptEncrypt(hPublicKey, 0, (i == dwBlockCount - 1) ? TRUE : FALSE, 0, &pData[i * dwBlockSize], &dwBlockDataLen, &encryptedData[i * dwBlockSize], &dwEncryptedDataLen))
                {
                    encryptedData.clear();
                    break;
                }
            }

            success = encryptedData.size() > 0;
        }
    }

    return success;
}

// RSA 解密
bool DecryptRSA(HCRYPTKEY hPrivateKey, const BYTE* pEncryptedData, DWORD dwEncryptedDataLen, vector<BYTE>& decryptedData)
{
    bool success = false;

    DWORD dwBlockLen = 0;
    DWORD dwDecryptedLen = 0;

    // 获取 RSA 解密块大小
    if (CryptGetKeyParam(hPrivateKey, KP_BLOCKLEN, (BYTE*)&dwBlockLen, &dwDecryptedLen, 0))
    {
        DWORD dwPadding = 0;

        // 计算 RSA 解密填充长度
        if (CryptGetKeyParam(hPrivateKey, KP_PADDING, (BYTE*)&dwPadding, &dwDecryptedLen, 0))
        {
            DWORD dwBlockSize = (dwBlockLen + 7) / 8;
            DWORD dwBlockCount = (dwEncryptedDataLen + dwBlockSize - 1) / dwBlockSize;

            decryptedData.resize(dwBlockCount * dwBlockSize);

            for (DWORD i = 0; i < dwBlockCount; i++)
            {
                DWORD dwEncryptedBlockLen = min(dwEncryptedDataLen - i * dwBlockSize, dwBlockSize);
                DWORD dwDecryptedBlockLen = decryptedData.size() - i * dwBlockSize;

                if (!CryptDecrypt(hPrivateKey, 0, (i == dwBlockCount - 1) ? TRUE : FALSE, 0, (BYTE*)&pEncryptedData[i * dwBlockSize], &dwEncryptedBlockLen, &decryptedData[i * dwBlockSize], &dwDecryptedBlockLen))
                {
                    decryptedData.clear();
                    break;
                }
            }

            success = decryptedData.size() > 0;
        }
    }

    return success;
}

int main()
{
    // 获取 CSP 句柄
    HCRYPTPROV hProv = 0;

    if (CryptAcquireContext(&hProv, NULL, MS_ENH_RSA_AES_PROV, PROV_RSA_AES, CRYPT_VERIFYCONTEXT))
    {
        HCRYPTKEY hPublicKey = 0;
        HCRYPTKEY hPrivateKey = 0;

        // 生成 RSA 公钥和私钥
        if (GenerateRSAKeys(hProv, hPublicKey, hPrivateKey))
        {
            string message;

            // 输入需要加密的信息
            cout << "请输入需要加密的信息：";
            getline(cin, message);

            // RSA 加密
            vector<BYTE> encryptedData;

            if (EncryptRSA(hPublicKey, (BYTE*)message.c_str(), message.length(), encryptedData))
            {
                string encryptedMessage((char*)&encryptedData[0], encryptedData.size());

                // RSA 解密
                vector<BYTE> decryptedData;

                if (DecryptRSA(hPrivateKey, &encryptedData[0], encryptedData.size(), decryptedData))
                {
                    string decryptedMessage((char*)&decryptedData[0], decryptedData.size());

                    // 输出加密和解密结果
                    cout << "加密后的信息：" << encryptedMessage << endl;
                    cout << "解密后的信息：" << decryptedMessage << endl;
                }
            }

            // 释放 RSA 公钥和私钥
            CryptDestroyKey(hPublicKey);
            CryptDestroyKey(hPrivateKey);
        }

        // 释放 CSP 句柄
        CryptReleaseContext(hProv, 0);
    }

    return 0;
}

需要注意的是，此代码使用 Microsoft Cryptographic API (CryptoAPI) 实现 RSA 加密和解密。在编译此代码之前，请确保已将 `crypt32.lib` 库添加到项目中。