加密技術在C#中的應用，包括：散列演算法，對稱加密技術，非對稱加密技術，數字簽名的簡單介紹 ...
本文是利用一個簡單的小例子，簡述C#中和加密術有關的內容，僅供學習參考用。
概述
隨著信息技術的發展，電腦網路為信息的獲取、傳輸、處理、利用與共用提供了一個高效、快捷、安全的通信環境和傳輸通道，網路信息安全也變得越來越重要。信息安全主要包括兩個方面的內容：信息存儲安全和信息傳輸安全。保證網路中信息安全的主要技術是數據的加密與解密。如下圖示，說明瞭加密與解密的過程。
公式演算法表示如下：
加密公式：c=Eke(m) （11.1） 解密公式：m=Dkd(c) （11.2）其中m代表明文，c代表密文，E是加密演算法，D是解密演算法，參數ke稱為加密密鑰，參數kd稱為解密密鑰
涉及知識點
- HASH演算法 ：散列函數是現代密碼系統的基礎。這些函數將任意長度的二進位字元串映射為固定長度的二進位字元串（稱為散列值）
- 對稱加密演算法：指對信息的加密和解密都使用相同的密鑰。
- 非對稱加密演算法：非對稱加密演算法對信息的加密與解密使用不同的密鑰，用來加密的密鑰是可以公開的，用來解密的密鑰需要保密
- 數字簽名術：數字簽名技術結合散列演算法和非對稱加密技術來進行篡改檢測和解決相關的身份驗證問題。這就像在現實生活中用親筆簽名來保證文件或資料的真實性一樣。
散列演算法
散列演算法主要有MD5【Message Digest Algorithm】，RIPEMD160【RACE Integrity Primitives Evaluation Message Digest】和SHA【Secure Hash Algorithm】，SHA又分為SHA1，SHA256，SHA384，SHA512，【散列演算法不可逆，是單向操作】如下如所示：
關於散列演算法，效果圖如下：
HASH演算法核心代碼如下：
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Security.Cryptography; 5 using System.Text; 6 using System.Threading.Tasks; 7 8 namespace DemoCrtpto 9 { 10 /// <summary> 11 /// 信息摘要幫助類 12 /// </summary> 13 public class HashHelper 14 { 15 #region 信息摘要 16 17 /// <summary> 18 /// MD5信息摘要 19 /// </summary> 20 /// <param name="source"></param> 21 /// <returns></returns> 22 public static string GetInfoByMd5(string source) 23 { 24 HashAlgorithm hash = getHashAlgorithm(HashType.MD5); 25 return Encrypto(hash, source); 26 } 27 28 public static string GetInfoBySHA1(string source) 29 { 30 HashAlgorithm hash = getHashAlgorithm(HashType.SHA1); 31 return Encrypto(hash, source); 32 } 33 34 public static string GetInfoBySHA256(string source) 35 { 36 HashAlgorithm hash = getHashAlgorithm(HashType.SHA256); 37 return Encrypto(hash, source); 38 } 39 40 public static string GetInfoBySHA384(string source) 41 { 42 HashAlgorithm hash = getHashAlgorithm(HashType.SHA384); 43 return Encrypto(hash, source); 44 } 45 46 public static string GetInfoBySHA512(string source) 47 { 48 HashAlgorithm hash = getHashAlgorithm(HashType.SHA512); 49 return Encrypto(hash, source); 50 } 51 52 public static string GetInfoByRipeMD(string source) 53 { 54 HashAlgorithm hash = getHashAlgorithm(HashType.RIPEMD); 55 return Encrypto(hash, source); 56 } 57 58 #endregion 59 60 /// <summary> 61 /// 根據類型獲取摘要演算法名稱 62 /// </summary> 63 /// <param name="t"></param> 64 /// <returns></returns> 65 private static HashAlgorithm getHashAlgorithm(HashType t) { 66 HashAlgorithm hash; 67 switch (t) { 68 case HashType.MD5: 69 hash = new MD5CryptoServiceProvider(); 70 break; 71 case HashType.SHA1: 72 hash = new SHA1Managed(); 73 break; 74 case HashType.SHA256: 75 hash = new SHA256Managed(); 76 break; 77 case HashType.SHA384: 78 hash = new SHA384Managed(); 79 break; 80 case HashType.SHA512: 81 hash = new SHA512Managed(); 82 break; 83 case HashType.RIPEMD: 84 hash = new RIPEMD160Managed(); 85 break; 86 default: 87 hash = new MD5CryptoServiceProvider(); 88 break; 89 } 90 return hash; 91 } 92 93 /// <summary> 94 /// 加密 95 /// </summary> 96 /// <param name="hash"></param> 97 /// <param name="source"></param> 98 /// <returns></returns> 99 private static string Encrypto(HashAlgorithm hash, string source) { 100 string dest = string.Empty; 101 try 102 { 103 byte[] btSource = Encoding.Default.GetBytes(source); 104 byte[] btDest = hash.ComputeHash(btSource); 105 dest = Convert.ToBase64String(btDest, 0, btDest.Length); 106 } 107 catch (Exception ex) 108 { 109 throw ex; 110 } 111 return dest; 112 } 113 } 114 115 /// <summary> 116 /// 信息摘要類型 117 /// </summary> 118 public enum HashType { 119 MD5=0, 120 SHA1=1, 121 SHA256=2, 122 SHA384=3, 123 SHA512=4, 124 RIPEMD=5 125 } 126 }View Code
對稱加密演算法
關於對稱加密演算法，主要有DES【Data Encryption Standard / 數據加密標準】 , 3DES【三重數據加密演算法】,RC2【Rivest Cipher】，Rijndael【又稱AES:Advanced Encryption Standard】。如下圖所示：
關於對稱加密演算法，效果圖如下：
對稱加密演算法的核心代碼如下：
1 using System; 2 using System.Collections.Generic; 3 using System.IO; 4 using System.Linq; 5 using System.Security.Cryptography; 6 using System.Text; 7 using System.Threading.Tasks; 8 9 namespace DemoCrtpto 10 { 11 /// <summary> 12 /// 對稱加密演算法幫助類 13 /// </summary> 14 public class SymHelper 15 { 16 #region DES加密 17 18 /// <summary> 19 /// DES加密 20 /// </summary> 21 /// <param name="source"></param> 22 /// <param name="key"></param> 23 /// <param name="iv"></param> 24 /// <returns></returns> 25 public static string GetEnCryptoInfoByDES(string source, string key, string iv) 26 { 27 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.DES); 28 return Encrypto(sym, source, key, iv); 29 30 } 31 32 /// <summary> 33 /// DES解密 34 /// </summary> 35 /// <param name="dest"></param> 36 /// <param name="key"></param> 37 /// <param name="iv"></param> 38 /// <returns></returns> 39 public static string GetDeCryptoInfoByDES(string dest, string key, string iv) 40 { 41 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.DES); 42 return Decrypto(sym, dest, key, iv); 43 44 } 45 46 #endregion 47 48 #region RC2加密與解密 49 50 /// <summary> 51 /// RC2加密 52 /// </summary> 53 /// <param name="source"></param> 54 /// <param name="key"></param> 55 /// <param name="iv"></param> 56 /// <returns></returns> 57 public static string GetEnCryptoInfoByRC2(string source, string key, string iv) 58 { 59 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.RC2); 60 return Encrypto(sym, source, key, iv); 61 62 } 63 64 /// <summary> 65 /// RC2解密 66 /// </summary> 67 /// <param name="dest"></param> 68 /// <param name="key"></param> 69 /// <param name="iv"></param> 70 /// <returns></returns> 71 public static string GetDeCryptoInfoByRC2(string dest, string key, string iv) 72 { 73 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.RC2); 74 return Decrypto(sym, dest, key, iv); 75 76 } 77 78 #endregion 79 80 #region 3DES加密與解密 81 82 /// <summary> 83 /// 3DES加密 84 /// </summary> 85 /// <param name="source"></param> 86 /// <param name="key"></param> 87 /// <param name="iv"></param> 88 /// <returns></returns> 89 public static string GetEnCryptoInfoBy3DES(string source, string key, string iv) 90 { 91 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.TripleDES); 92 return Encrypto(sym, source, key, iv); 93 94 } 95 96 /// <summary> 97 /// 3DES解密 98 /// </summary> 99 /// <param name="dest"></param> 100 /// <param name="key"></param> 101 /// <param name="iv"></param> 102 /// <returns></returns> 103 public static string GetDeCryptoInfoBy3DES(string dest, string key, string iv) 104 { 105 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.TripleDES); 106 return Decrypto(sym, dest, key, iv); 107 108 } 109 110 #endregion 111 112 #region Rijndael加密與解密 113 114 /// <summary> 115 /// Rijndael加密 116 /// </summary> 117 /// <param name="source"></param> 118 /// <param name="key"></param> 119 /// <param name="iv"></param> 120 /// <returns></returns> 121 public static string GetEnCryptoInfoByRijndael(string source, string key, string iv) 122 { 123 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.Rijndael); 124 return Encrypto(sym, source, key, iv); 125 126 } 127 128 129 /// <summary> 130 /// Rijndael解密 131 /// </summary> 132 /// <param name="dest"></param> 133 /// <param name="key"></param> 134 /// <param name="iv"></param> 135 /// <returns></returns> 136 public static string GetDeCryptoInfoByRijndael(string dest, string key, string iv) 137 { 138 SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.Rijndael); 139 return Decrypto(sym, dest, key, iv); 140 } 141 142 #endregion 143 144 public static SymmetricAlgorithm getSymmetricAlgorithm(SymType t) 145 { 146 SymmetricAlgorithm sym; 147 switch (t) 148 { 149 case SymType.DES: 150 sym = new DESCryptoServiceProvider(); 151 break; 152 case SymType.RC2: 153 sym = new RC2CryptoServiceProvider(); 154 break; 155 case SymType.TripleDES: 156 sym = new TripleDESCryptoServiceProvider(); 157 break; 158 case SymType.Rijndael: 159 sym = new RijndaelManaged(); 160 break; 161 default: 162 sym = new DESCryptoServiceProvider(); 163 break; 164 } 165 return sym; 166 } 167 168 /// <summary> 169 /// 加密 170 /// </summary> 171 /// <param name="sym"></param> 172 /// <param name="source"></param> 173 /// <param name="key"></param> 174 /// <param name="iv"></param> 175 /// <returns></returns> 176 private static string Encrypto(SymmetricAlgorithm sym, string source, string key, string iv) 177 { 178 string dest = string.Empty; 179 try 180 { 181 byte[] btnSource = Encoding.Default.GetBytes(source); 182 //1.創建對稱加密演算法實例創建對稱加密演算法實例 183 sym.Mode = CipherMode.CBC; 184 int keyLen = sym.LegalKeySizes[0].MaxSize / 8; 185 int ivLen = sym.BlockSize / 8; 186 if (key.Length < keyLen) 187 { 188 key = key.PadRight(keyLen, '0'); 189 } 190 if (iv.Length < ivLen) 191 { 192 iv = iv.PadRight(ivLen, '0'); 193 } 194 //使用 PBKDF1 演算法的擴展從密碼派生密鑰 195 PasswordDeriveBytes pkey = new PasswordDeriveBytes(key, 196 ASCIIEncoding.ASCII.GetBytes("123456")); 197 198 //2.設置初始化參數，包括密鑰和初始化向量等 199 sym.Key = pkey.GetBytes(key.Length); //Encoding.Default.GetBytes(key); 200 sym.IV = Encoding.Default.GetBytes(iv); 201 //3.使用CreateEncryptor方法創建加密實例 202 ICryptoTransform trans = sym.CreateEncryptor(); 203 //4.創建加密流 204 MemoryStream ms = new MemoryStream(); 205 CryptoStream cs = new CryptoStream(ms, trans, CryptoStreamMode.Write); 206 //5.利用加密流進行數據加密 207 cs.Write(btnSource, 0, btnSource.Length); 208 cs.FlushFinalBlock(); 209 //6.返回密文 210 byte[] cryptoByte = ms.ToArray(); 211 dest = Convert.ToBase64String(cryptoByte, 0, cryptoByte.GetLength(0)); 212 } 213 catch (Exception ex) 214 { 215 throw ex; 216 } 217 return dest; 218 } 219 220 /// <summary> 221 /// 解密 222 /// </summary> 223 /// <param name="sym"></param> 224 /// <param name="dest"></param> 225 /// <param name="key"></param> 226 /// <param name="iv"></param> 227 /// <returns></returns> 228 private static string Decrypto(SymmetricAlgorithm sym, string dest, string key, string iv) 229 { 230 string source = string.Empty; 231 try 232 { 233 byte[] btnDest = Convert.FromBase64String(dest); 234 //1.創建對稱加密演算法實例創建對稱加密演算法實例 235 sym.Mode = CipherMode.CBC; 236 int keyLen = sym.LegalKeySizes[0].MaxSize / 8; 237 int ivLen = sym.BlockSize / 8; 238 if (key.Length < keyLen) 239 { 240 key = key.PadRight(keyLen, '0'); 241 } 242 if (iv.Length < ivLen) 243 { 244 iv = iv.PadRight(ivLen, '0'); 245 } 246 //使用 PBKDF1 演算法的擴展從密碼派生密鑰 247 PasswordDeriveBytes pkey = new PasswordDeriveBytes(key, 248 ASCIIEncoding.ASCII.GetBytes("123456")); 249 //2.設置初始化參數，包括密鑰和初始化向量等 250 sym.Key = pkey.GetBytes(key.Length); //Encoding.Default.GetBytes(key); 251 sym.IV = Encoding.Default.GetBytes(iv); 252 //3.使用CreateDecryptor方法創建解密實例 253 ICryptoTransform trans = sym.CreateDecryptor(); 254 //4.創建解密流 255 MemoryStream ms = new MemoryStream(btnDest, 0, btnDest.Length);
