请问关于c的具体应用场景有哪些？

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cpp// 加密字符串std::string des_cbc_zero_encrypt(const std::string& clearText, const std::string& key) { static unsigned char cbc_iv[8]={'j', 'k', 't', '1', '2', '3', '4', '5'}; std::string strCipherText; // ...}

c++代码 //加密 std::string des_cbc_zero_encrypt(const std::string &clearText, const std::string &key) { static unsigned char cbc_iv[8] = {'j', 'k', 't', '1', '2', '3', '4', '5'}; //初始化IV向量 std::string strCipherText; DES_cblock keyEncrypt, ivec; memset(keyEncrypt, 0, 8); if (key.length() <= 8) memcpy(keyEncrypt, key.c_str(), key.length()); else memcpy(keyEncrypt, key.c_str(), 8); DES_key_schedule keySchedule; //密钥表 DES_set_key_unchecked(&keyEncrypt, &keySchedule); //设置密钥，且不检测密钥奇偶性 memcpy(ivec, cbc_iv, sizeof(cbc_iv)); // 循环加密，每8字节一次 const_DES_cblock inputText; DES_cblock outputText; std::vector<unsigned char> vecCiphertext; unsigned char tmp[8]; for (int i = 0; i < clearText.length() / 8; i++) { memcpy(inputText, clearText.c_str() + i * 8, 8); DES_ncbc_encrypt(inputText, outputText, 8, &keySchedule, &ivec, DES_ENCRYPT); //加密 memcpy(tmp, outputText, 8); for (int j = 0; j < 8; j++) vecCiphertext.push_back(tmp[j]); //重置ivec memcpy(ivec, outputText, 8); } if (clearText.length() % 8 != 0) { int tmp1 = clearText.length() / 8 * 8; int tmp2 = clearText.length() - tmp1; memset(inputText, 0, 8); memcpy(inputText, clearText.c_str() + tmp1, tmp2); // 加密函数 DES_ncbc_encrypt(inputText, outputText, 8, &keySchedule, &ivec, DES_ENCRYPT); //加密 memcpy(tmp, outputText, 8); for (int j = 0; j < 8; j++) vecCiphertext.push_back(tmp[j]); } strCipherText.clear(); strCipherText.assign(vecCiphertext.begin(), vecCiphertext.end()); return strCipherText; } //加密 cbc pkcs5padding 自己实现 //pkcs7padding 跟 pkcs5padding是一样的 std::string des_cbc_pkcs5_encrypt(const std::string &clearText, const std::string &key) { static unsigned char cbc_iv[8] = {'j', 'k', 't', '1', '2', '3', '4', '5'}; //初始化IV向量 std::string strCipherText; DES_cblock keyEncrypt, ivec; memset(keyEncrypt, 0, 8); if (key.length() <= 8) memcpy(keyEncrypt, key.c_str(), key.length()); else memcpy(keyEncrypt, key.c_str(), 8); DES_key_schedule keySchedule; //密钥表 DES_set_key_unchecked(&keyEncrypt, &keySchedule); //设置密钥，且不检测密钥奇偶性 memcpy(ivec, cbc_iv, sizeof(cbc_iv)); // 循环加密，每8字节一次 const_DES_cblock inputText; DES_cblock outputText; std::vector<unsigned char> vecCiphertext; unsigned char tmp[8]; for (int i = 0; i < clearText.length() / 8; i++) { memcpy(inputText, clearText.c_str() + i * 8, 8); DES_ncbc_encrypt(inputText, outputText, 8, &keySchedule, &ivec, DES_ENCRYPT); //加密 memcpy(tmp, outputText, 8); for (int j = 0; j < 8; j++) vecCiphertext.push_back(tmp[j]); //重置ivec memcpy(ivec, outputText, 8); } if (clearText.length() % 8 != 0) { int tmp1 = clearText.length() / 8 * 8; int tmp2 = clearText.length() - tmp1; memset(inputText,(8-tmp2), 8); memcpy(inputText, clearText.c_str() + tmp1, tmp2); } else { memset(inputText,8, 8); } // 加密函数 DES_ncbc_encrypt(inputText, outputText, 8, &keySchedule, &ivec, DES_ENCRYPT); //加密 memcpy(tmp, outputText, 8); for (int j = 0; j < 8; j++) vecCiphertext.push_back(tmp[j]); strCipherText.clear(); strCipherText.assign(vecCiphertext.begin(), vecCiphertext.end()); return strCipherText; } //解密 cbc pkcs5padding 自己实现 //zeropadding / pkcs7padding 跟 pkcs5padding是一样的 //Base64Decode先将数据解密 std::string des_cbc_pkcs5_decrypt(const std::string &cipherText, const std::string &key) { static unsigned char cbc_iv[8] = {'j', 'k', 't', '1', '2', '3', '4', '5'}; //初始化IV向量 std::string clearText; DES_cblock keyEncrypt, ivec; memset(keyEncrypt, 0, 8); if (key.length() <= 8) memcpy(keyEncrypt, key.c_str(), key.length()); else memcpy(keyEncrypt, key.c_str(), 8); DES_key_schedule keySchedule; //密钥表 DES_set_key_unchecked(&keyEncrypt, &keySchedule); //设置密钥，且不检测密钥奇偶性 memcpy(ivec, cbc_iv, sizeof(cbc_iv)); // 循环解密，每8字节一次 const_DES_cblock inputText; DES_cblock outputText; std::vector<unsigned char> vecCleartext; unsigned char tmp[8]; for (int i = 0; i < cipherText.length() / 8; i++) { memcpy(inputText, cipherText.c_str() + i * 8, 8); DES_ncbc_encrypt(inputText, outputText, 8, &keySchedule, &ivec, DES_DECRYPT); //解密 memcpy(tmp, outputText, 8); for (int j = 0; j < 8; j++) vecCleartext.push_back(tmp[j]); //重置ivec //memcpy(ivec, outputText, 8); //解密过程不需要用前一块的结果作为下一块的IV } if (clearText.length() % 8 != 0) { int tmp1 = clearText.length() / 8 * 8; int tmp2 = clearText.length() - tmp1; memset(inputText,0, tmp2); memcpy(inputText, cipherText.c_str() + tmp1, tmp2); DES_ncbc_encrypt(inputText, outputText, tmp2, &keySchedule, &ivec, DES_DECRYPT); //解密 memcpy(tmp, outputText, tmp2); for (int j = 0; j < 8; j++) vecCleartext.push_back(tmp[j]); } clearText.clear(); clearText.assign(vecCleartext.begin(), vecCleartext.end()); return clearText; } //使用base64 std::string Base64Decode(const std::string &input, bool with_new_line) { BIO *b64 = nullptr; BIO *bmem = nullptr; std::string ret = ""; b64 = BIO_new(BIO_f_base64()); if (!with_new_line) { BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL); } bmem = BIO_new_mem_buf(input.c_str(), input.length()); bmem = BIO_push(b64, bmem); char *buffer = (char *)malloc(input.length()); memset(buffer, 0, input.length()); int len = BIO_read(bmem, buffer, input.length()); if (len > 0) { ret = std::string(buffer, len); } BIO_free_all(bmem); free(buffer); return ret; } 搬运www.cnblogs.com/azbane/p/10179660.html

C# public static string DESDecrypt(string data, string key, string iv) { byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key); byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv); byte[] byEnc; try { byEnc = Convert.FromBase64String(data); DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider(); MemoryStream ms = new MemoryStream(byEnc); CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read); StreamReader sr = new StreamReader(cst); return sr.ReadToEnd(); } catch { return null; } } public static string DESEncrypt(string data, string key, string iv) { byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key); byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv); DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider(); MemoryStream ms = new MemoryStream(); CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write); StreamWriter sw = new StreamWriter(cst); sw.Write(data); sw.Flush(); cst.FlushFinalBlock(); sw.Flush(); return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length); }