抽象類HashAlgorithm
- 抽象類MD5
  - MD5CryptoServiceProvider
- SHA1
  - SHA1CryptoServiceProvider密封類：調(diào)用Windows Crypto API
  - SHA1Managed普通類：用托管代碼寫的
- SHA256
  - SHA256CryptoServiceProvider
  - SHA256Managed
- SHA384
- SHA512

對字節(jié)數(shù)組或流散列運算

    class Program 
    { 
        static void Main(string[] args) 
        { 
            string str = "Hello World"; 
            HashAlgorithm hashAlgorithm = HashAlgorithm.Create(HashAlgorithmType.SHA1); 
            byte[] data = Encoding.Default.GetBytes(str); 
            byte[] digest = hashAlgorithm.ComputeHash(data); 
            foreach (byte b in digest) 
            { 
                Console.Write("{0:X}",b); 
            } 
            Console.ReadKey(); 
        } 
    }
 
    public class HashAlgorithmType 
    { 
        public const string SHA1 = "SHA1"; 
        public const string SHA256 = "SHA256"; 
        public const string SHA384 = "SHA384"; 
        public const string SHA512 = "SHA512"; 
        public const string MD5 = "MD5"; 
    }

密匙散列運算

string key = "secret key"; 
byte[] data = Encoding.Default.GetBytes(key); 
KeyedHashAlgorithm kha = new HMACSHA1(); 
byte[] digest = kha.ComputeHash(data); 
foreach (byte b in digest) 
{ 
    Console.Write("{0:x}",b); 
}

對稱加密和解密

SymmetricAlgorithm
- DES
  - DESCryptoServiceProvider
- TripleDES
  - TripleDESCryptoServiceProvider
- Rijndael
  - RijindaelManaged
- RC2
  - RC2CryptoServiceProvider

IV:Initialization vector初始化向量：

為了解決加密字符串加密后仍然有重復部分，引入IV，加密字符串即使有重復，也會被打亂。
IV值可以隨意指定，但長度固定，通常為64位byte類型
密匙長度也是固定的，通常為128位或196位byte類型

使用Encoding類將字符串轉換為byte[]：

如果使用UTF8，會變長編碼

加密解密方法：

加密方法：CreateEncryptor()，返回ICryptoTransform接口類型
解密方法：CreateDecryptor()，返回ICrtyptoTransform接口類型

明文流和加密流的轉換：

    public CryptoStream(Stream stream, ICryptoTransform transform, CryptoStreamMode mode)
 
    class Program 
    { 
        static void Main(string[] args) 
        { 
            #region 對稱加密和解密
 
            string key = "secret key"; 
            string str = "Hello World";
 
            //加密 
            string encryptedText = SymmetricCryptoHelper.Encrypt(str, key); 
            Console.WriteLine(encryptedText);
 
            //解密 
            string clearText = SymmetricCryptoHelper.Decrypt(encryptedText, key); 
            Console.WriteLine(clearText);
 
            Console.ReadKey();
 
            #endregion 
        } 
    }
 
    //對稱加密幫助類 
    public class SymmetricCryptoHelper 
    { 
        private ICryptoTransform encryptor;  //加密器對象 
        private ICryptoTransform decryptor; //解密器對象 
        private const int BufferSize = 1024;
 
        public SymmetricCryptoHelper(string algorithmName, byte[] key) 
        { 
            SymmetricAlgorithm provider = SymmetricAlgorithm.Create(algorithmName); 
            provider.Key = key; 
            provider.IV = new byte[] { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
 
            encryptor = provider.CreateEncryptor(); 
            decryptor = provider.CreateDecryptor(); 
        }
 
        public SymmetricCryptoHelper(byte[] key) : this("TripleDES", key){}
 
        //加密算法 
        public string Encrypt(string clearText) 
        { 
            //創(chuàng)建明文流 
            byte[] clearBuffer = Encoding.UTF8.GetBytes(clearText); 
            //byte[] clearBuffer = Encoding.Default.GetBytes(clearText); 
            MemoryStream clearStream = new MemoryStream(clearBuffer);
 
            //創(chuàng)建空的密文流 
            MemoryStream encryptedStream = new MemoryStream();
 
            //明文流和密文流轉換流，準備寫到密文流中 
            CryptoStream cryptoStream = new CryptoStream(encryptedStream, encryptor, CryptoStreamMode.Write); 
           
            int bytesRead = 0; 
            byte[] buffer = new byte[BufferSize]; 
            do 
            { 
                //讀取明文流到buffer中 
                bytesRead = clearStream.Read(buffer, 0, BufferSize); 
                //通過CryptoStream將buffer中的明文流字節(jié)數(shù)組寫到明文流中 
                cryptoStream.Write(buffer, 0, bytesRead); 
            } while (bytesRead > 0);
 
            cryptoStream.FlushFinalBlock();
 
            //獲取加密后的字節(jié)數(shù)組 
            buffer = encryptedStream.ToArray();
 
            //將加密后的字節(jié)數(shù)組轉換成字符串 
            string encryptedText = Convert.ToBase64String(buffer); 
            return encryptedText; 
        }
 
        //解密算法 
        public string Decrypt(string encryptedText) 
        { 
            //把加密字符串轉換為加密字節(jié)數(shù)組 
            byte[] encryptedBuffer = Convert.FromBase64String(encryptedText); 
            //創(chuàng)建密文流 
            Stream encryptedStream = new MemoryStream(encryptedBuffer);
 
            //創(chuàng)建空的明文流 
            MemoryStream clearStream = new MemoryStream();
 
            //創(chuàng)建明文流和密文流的轉化流，讀取密文流 
            CryptoStream cryptoStream = new CryptoStream(encryptedStream, decryptor, CryptoStreamMode.Read);
 
            int bytesRead = 0; 
            byte[] buffer = new byte[BufferSize];
 
            do 
            { 
                //通過CryptoStream讀取密文流到Buffer 
                bytesRead = cryptoStream.Read(buffer, 0, BufferSize); 
                //把Buffer中的密文流寫到明文流中 
                clearStream.Write(buffer, 0, bytesRead); 
            } while (bytesRead > 0);
 
            //將明文流轉換成字節(jié)數(shù)組 
            buffer = clearStream.GetBuffer();
 
            string clearText = Encoding.UTF8.GetString(buffer, 0, (int)clearStream.Length); 
            //string clearText = Encoding.Default.GetString(buffer, 0, (int)clearStream.Length); 
            return clearText; 
        }
 
        //密匙加密 
        public static string Encrypt(string clearText, string key) 
        { 
            byte[] keyData = new byte[16]; //TripleDES密匙固定長度為16個字節(jié)
 
            //把密匙字符串轉換成字節(jié)數(shù)組 
            byte[] sourceData = Encoding.Default.GetBytes(key); 
            int copyBytes = 16; 
            if (sourceData.Length < 16) 
            { 
                copyBytes = sourceData.Length; 
            }
 
            //把密匙數(shù)組復制到keyData字節(jié)數(shù)組中 
            Array.Copy(sourceData,keyData,copyBytes);
 
            SymmetricCryptoHelper helper = new SymmetricCryptoHelper(keyData); 
            return helper.Encrypt(clearText); 
        }
 
        //密匙解密 
        public static string Decrypt(string encryptedText, string key) 
        { 
            byte[] keyData = new byte[16]; 
            byte[] sourceData = Encoding.Default.GetBytes(key); 
            int copyBytes = 16; 
            if (sourceData.Length < 16) 
            { 
                copyBytes = sourceData.Length; 
            } 
            Array.Copy(sourceData,keyData,copyBytes);
 
            SymmetricCryptoHelper helper = new SymmetricCryptoHelper(keyData); 
            return helper.Decrypt(encryptedText); 
        } 
    }

非對稱加密

AsymmetricAlgorithm
- RSA
  - RSACryptoServiceProvider
- DSA
  - DSACryptoServiceProvider：只能進行認證模式，即數(shù)字簽名

對稱加密中的密匙：

密匙為由開發(fā)者設定的字符串

非對稱加密中的密匙：

通常是自動生成，不同的算法有不同的密匙格式
在創(chuàng)建RSACryptoServiceProvider實例時，會自動創(chuàng)建一個公/私密匙對。在實例上調(diào)用ToXmlString()方法獲得。

RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
string publicPrivate = provider.ToXmlString(true);//獲得公/私匙對
//string publicOnly = provider.ToXmlString(false); //只獲得公匙
Console.Write(publicPrivate);
Console.ReadKey();

非對稱加密幫助類

    //非對稱加密幫助類 
    public class RSACryptoHelper 
    { 
        //加密 
        public static string Encrypt(string publicKeyXml, string plainText) 
        { 
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 
            provider.FromXmlString(publicKeyXml); //使用公匙初始化對象 
            byte[] plainData = Encoding.Default.GetBytes(plainText); 
            byte[] encryptedData = provider.Encrypt(plainData, true); 
            return Convert.ToBase64String(encryptedData); 
        }
 
        //解密 
        public static string Decrypt(string privateKeyXml, string encryptedText) 
        { 
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 
            provider.FromXmlString(privateKeyXml); 
            byte[] encryptedData = Convert.FromBase64String(encryptedText); 
            byte[] plainData = provider.Decrypt(encryptedData, true); 
            string plainText = Encoding.Default.GetString(plainData); 
            return plainText; 
        } 
    }

數(shù)字簽名

RSACryptoServiceProvider或DSACryptoServiceProvider
SignData()對摘要進行簽名，并返回簽名后的摘要。
VerifyData()得出本地摘要，并解密傳遞進來的原始摘要，對比返回bool類型結果。

數(shù)字簽名幫助類

    public class RSACryptoHelper 
    { 
        public static string SignData(string plainText, string privateKeyXml) 
        { 
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 
            provider.FromXmlString(privateKeyXml);
 
            byte[] plainData = Encoding.Default.GetBytes(plainText); 
            //設置獲取摘要的算法 
            HashAlgorithm sha1 = HashAlgorithm.Create("SHA1"); 
            //獲取簽名過的摘要,是使用私匙加密過的摘要 
            byte[] signedDigest = provider.SignData(plainData, sha1); 
            return Convert.ToBase64String(signedDigest); 
        }
 
        public static bool VerifyData(string plainText, string signature, string publicKeyXml) 
        { 
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 
            provider.FromXmlString(publicKeyXml);
 
            byte[] plainData = Encoding.Default.GetBytes(plainText); 
            byte[] signedDigest = Convert.FromBase64String(signature);
 
            HashAlgorithm sha1 = HashAlgorithm.Create("SHA1"); 
            bool isDataIntact = provider.VerifyData(plainData, sha1, signedDigest); 
            return isDataIntact; 
        }
 
        //使用SingnHash 
        public static string SignData2(string plainText, string privateKeyXml) 
        { 
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 
            provider.FromXmlString(privateKeyXml); 
            byte[] plainData = Encoding.Default.GetBytes(plainText);
 
            //設置獲取摘要的算法 
            HashAlgorithm sha1 = HashAlgorithm.Create("SHA1"); 
            //獲得原始摘要 
            byte[] digestData = sha1.ComputeHash(plainData); 
            //對元素摘要進行簽名 
            byte[] signedDigest = provider.SignHash(digestData, "SHA1"); 
            return Convert.ToBase64String(signedDigest); 
        }
 
        //使用VerifyHash 
        public static bool VerifyData2(string plainText, string signedDigest, string publicKeyXml) 
        { 
            RSACryptoServiceProvider provider = new RSACryptoServiceProvider(); 
            provider.FromXmlString(publicKeyXml);
 
            byte[] plainData = Encoding.Default.GetBytes("SHA1"); 
            byte[] signedDigestData = Convert.FromBase64String(signedDigest);
 
            //獲得本地摘要 
            HashAlgorithm sha1 = HashAlgorithm.Create("SHA1"); 
            byte[] digest = sha1.ComputeHash(plainData);
 
            //解密簽名 
            bool isDataIntact = provider.VerifyHash(digest, "SHA1", signedDigestData); 
            return isDataIntact; 
        } 
    }

到此這篇關于ASP.NET加密和解密的文章就介紹到這了。希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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