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所属分类：.NET技术
一、MD5不可逆加密
1.1-理解MD5
- MD5公开的算法，任何语言实现后其实都是一样的、通用的
- 不可逆加密：原文——加密——密文，密文无法解密出原文
1.2-MD5封装
using System.IO; using System.Security.Cryptography; /// <summary> /// 不可逆加密 /// 1 防止被篡改 /// 2 防止明文存储 /// 3 防止抵赖，数字签名 /// </summary> public class MD5Encrypt { #region MD5 /// <summary> /// MD5加密,和动网上的16/32位MD5加密结果相同, /// 使用的UTF8编码 /// </summary> /// <param name="source">待加密字串</param> /// <param name="length">16或32值之一,其它则采用.net默认MD5加密算法</param> /// <returns>加密后的字串</returns> public static string Encrypt(string source, int length = 32)//默认参数 { if (string.IsNullOrEmpty(source)) return string.Empty; HashAlgorithm provider = CryptoConfig.CreateFromName("MD5") as HashAlgorithm; byte[] bytes = Encoding.UTF8.GetBytes(source);//这里需要区别编码的 byte[] hashValue = provider.ComputeHash(bytes); StringBuilder sb = new StringBuilder(); switch (length) { case 16://16位密文是32位密文的9到24位字符 for (int i = 4; i < 12; i++) { sb.Append(hashValue[i].ToString("x2")); } break; case 32: for (int i = 0; i < 16; i++) { sb.Append(hashValue[i].ToString("x2")); } break; default: for (int i = 0; i < hashValue.Length; i++) { sb.Append(hashValue[i].ToString("x2")); } break; } return sb.ToString(); } #endregion MD5 #region MD5摘要 /// <summary> /// 获取文件的MD5摘要 /// </summary> /// <param name="fileName"></param> /// <returns></returns> public static string AbstractFile(string fileName) { using (FileStream file = new FileStream(fileName, FileMode.Open)) { return AbstractFile(file); } } /// <summary> /// 根据stream获取文件摘要 /// </summary> /// <param name="stream"></param> /// <returns></returns> public static string AbstractFile(Stream stream) { MD5 md5 = new MD5CryptoServiceProvider(); byte[] retVal = md5.ComputeHash(stream); StringBuilder sb = new StringBuilder(); for (int i = 0; i < retVal.Length; i++) { sb.Append(retVal[i].ToString("x2")); } return sb.ToString(); } #endregion }
1.3-MD5总结
- 相同原文加密的结果是一样的
- 不同长度的内容加密后都是32位，可以自行改变长度
- 原文件改动差别很小，结果差别很大
- 不管文件多大，都能产生32位长度的【摘要】，就是更具文件流进行加密的结果
- 文件内容有一点改动，结果变化非常大
- 文件内容不变，文件名变了，结果是不变的
1.4-MD5用途？
- 防篡改
- 源代码管理器
- 急速秒传
- 在本地进行MD5摘要，到服务器上去检查，如果存在就不需要上传，直接在服务器上复制一份，或者指向路径跳转一下。
- 密码保存：防止看到明文
- 密文是可见的，所以要求密码不能太检查；加盐（特殊字符+字母+数字）
- MD5是无法全部穷举出来的，无法全部解密出来的，像网上有很多这种；
- 防止抵赖，数字签名
- 吧一些内容摘要一下，不能抵赖。
二、对称可逆加密DES
2.1-理解DES
- 对称可逆加密是公开的算法，任何语言实现后其实都一样，通用的。
- 加密后能解密会原文，但是需要一个Key
- 加密key和加密Key是同一个，也就是开门和锁门都要用同一吧钥匙
- 优点：加密解密的速度快
- 缺点：问题是秘钥的安全（key在网络中传输呗窃取），不是很安全
理解什么是对称可逆加密：
- 对称：加密/解密是key要一模一样的
- 可逆：原文加密到密文，密文解密到原文
2.2-DES封装
/// <summary> /// Des加密 /// </summary> public class DesCrypto { //密钥 private const string sKey = "qJzGEh6hESZDVJeCnFPGuxzaiB7NLQM3"; //矢量，矢量可以为空 private const string sIV = "qcDY6X+aPLw="; //构造一个对称算法 private SymmetricAlgorithm mCSP = new TripleDESCryptoServiceProvider(); /// <summary> /// 构造函数 /// </summary> public DesCrypto() { } #region public string EncryptString(string Value) /// <summary> /// 加密字符串 /// </summary> /// <param name="Value">输入的字符串</param> /// <returns>加密后的字符串</returns> public string EncryptString(string Value) { ICryptoTransform ct; MemoryStream ms; CryptoStream cs; byte[] byt; mCSP.Key = Convert.FromBase64String(sKey); mCSP.IV = Convert.FromBase64String(sIV); //指定加密的运算模式 mCSP.Mode = System.Security.Cryptography.CipherMode.ECB; //获取或设置加密算法的填充模式 mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7; ct = mCSP.CreateEncryptor(mCSP.Key, mCSP.IV); byt = Encoding.UTF8.GetBytes(Value); ms = new MemoryStream(); cs = new CryptoStream(ms, ct, CryptoStreamMode.Write); cs.Write(byt, 0, byt.Length); cs.FlushFinalBlock(); cs.Close(); return Convert.ToBase64String(ms.ToArray()); } #endregion #region public string DecryptString(string Value) /// <summary> /// 解密字符串 /// </summary> /// <param name="Value">加过密的字符串</param> /// <returns>解密后的字符串</returns> public string DecryptString(string Value) { ICryptoTransform ct; MemoryStream ms; CryptoStream cs; byte[] byt; mCSP.Key = Convert.FromBase64String(sKey); mCSP.IV = Convert.FromBase64String(sIV); mCSP.Mode = System.Security.Cryptography.CipherMode.ECB; mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7; ct = mCSP.CreateDecryptor(mCSP.Key, mCSP.IV); byt = Convert.FromBase64String(Value); ms = new MemoryStream(); cs = new CryptoStream(ms, ct, CryptoStreamMode.Write); cs.Write(byt, 0, byt.Length); cs.FlushFinalBlock(); cs.Close(); return Encoding.UTF8.GetString(ms.ToArray()); } #endregion }
三、非对称可逆加密RSA
2.1-理解RSA
- 非对称可逆加密公开的算法，任何语言实现后其实都一样，通用的；
- 加密key和解密key不是一个，而是一对
- 加密key和解密key不能相互推到，有密文，没有解密key，也推导不出原文
- 缺点：速度不快
- 优点：安全性好
2.2-RSA封装
/// <summary> /// RSA加密解密及RSA签名和验证 /// </summary> public class RsaEncrypt { public RsaEncrypt() { } #region RSA 的密钥产生 /// <summary> /// RSA 的密钥产生 产生私钥 和公钥 /// </summary> /// <param name="xmlKeys"></param> /// <param name="xmlPublicKey"></param> public void RSAKey(out string xmlKeys, out string xmlPublicKey) { System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); xmlKeys = rsa.ToXmlString(true); xmlPublicKey = rsa.ToXmlString(false); } #endregion #region RSA的加密函数 //############################################################################## //RSA 方式加密 //说明KEY必须是XML的行式,返回的是字符串 //在有一点需要说明！！该加密方式有 长度 限制的！！ //############################################################################## //RSA的加密函数 string public string RSAEncrypt(string xmlPublicKey, string m_strEncryptString) { byte[] PlainTextBArray; byte[] CypherTextBArray; string Result; RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); PlainTextBArray = (new UnicodeEncoding()).GetBytes(m_strEncryptString); CypherTextBArray = rsa.Encrypt(PlainTextBArray, false); Result = Convert.ToBase64String(CypherTextBArray); return Result; } //RSA的加密函数 byte[] public string RSAEncrypt(string xmlPublicKey, byte[] EncryptString) { byte[] CypherTextBArray; string Result; RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); CypherTextBArray = rsa.Encrypt(EncryptString, false); Result = Convert.ToBase64String(CypherTextBArray); return Result; } #endregion #region RSA的解密函数 //RSA的解密函数 string public string RSADecrypt(string xmlPrivateKey, string m_strDecryptString) { byte[] PlainTextBArray; byte[] DypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPrivateKey); PlainTextBArray = Convert.FromBase64String(m_strDecryptString); DypherTextBArray = rsa.Decrypt(PlainTextBArray, false); Result = (new UnicodeEncoding()).GetString(DypherTextBArray); return Result; } //RSA的解密函数 byte public string RSADecrypt(string xmlPrivateKey, byte[] DecryptString) { byte[] DypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPrivateKey); DypherTextBArray = rsa.Decrypt(DecryptString, false); Result = (new UnicodeEncoding()).GetString(DypherTextBArray); return Result; } #endregion #region RSA数字签名 #region 获取Hash描述表 //获取Hash描述表 ，outofmemory.cn public bool GetHash(string m_strSource, ref byte[] HashData) { //从字符串中取得Hash描述 byte[] Buffer; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); Buffer = System.Text.Encoding.GetEncoding("GB2312").GetBytes(m_strSource); HashData = MD5.ComputeHash(Buffer); return true; } //获取Hash描述表 public bool GetHash(string m_strSource, ref string strHashData) { //从字符串中取得Hash描述 byte[] Buffer; byte[] HashData; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); Buffer = System.Text.Encoding.GetEncoding("GB2312").GetBytes(m_strSource); HashData = MD5.ComputeHash(Buffer); strHashData = Convert.ToBase64String(HashData); return true; } //获取Hash描述表 public bool GetHash(System.IO.FileStream objFile, ref byte[] HashData) { //从文件中取得Hash描述 System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); HashData = MD5.ComputeHash(objFile); objFile.Close(); return true; } //获取Hash描述表 public bool GetHash(System.IO.FileStream objFile, ref string strHashData) { //从文件中取得Hash描述 byte[] HashData; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); HashData = MD5.ComputeHash(objFile); objFile.Close(); strHashData = Convert.ToBase64String(HashData); return true; } #endregion #region RSA签名 //RSA签名 public bool SignatureFormatter(string p_strKeyPrivate, byte[] HashbyteSignature, ref byte[] EncryptedSignatureData) { System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPrivate); System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA); //设置签名的算法为MD5 RSAFormatter.SetHashAlgorithm("MD5"); //执行签名 EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); return true; } //RSA签名 public bool SignatureFormatter(string p_strKeyPrivate, byte[] HashbyteSignature, ref string m_strEncryptedSignatureData) { byte[] EncryptedSignatureData; System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPrivate); System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA); //设置签名的算法为MD5 RSAFormatter.SetHashAlgorithm("MD5"); //执行签名 EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); m_strEncryptedSignatureData = Convert.ToBase64String(EncryptedSignatureData); return true; } //RSA签名 public bool SignatureFormatter(string p_strKeyPrivate, string m_strHashbyteSignature, ref byte[] EncryptedSignatureData) { byte[] HashbyteSignature; HashbyteSignature = Convert.FromBase64String(m_strHashbyteSignature); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPrivate); System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA); //设置签名的算法为MD5 RSAFormatter.SetHashAlgorithm("MD5"); //执行签名 EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); return true; } //RSA签名 public bool SignatureFormatter(string p_strKeyPrivate, string m_strHashbyteSignature, ref string m_strEncryptedSignatureData) { byte[] HashbyteSignature; byte[] EncryptedSignatureData; HashbyteSignature = Convert.FromBase64String(m_strHashbyteSignature); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPrivate); System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA); //设置签名的算法为MD5 RSAFormatter.SetHashAlgorithm("MD5"); //执行签名 EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); m_strEncryptedSignatureData = Convert.ToBase64String(EncryptedSignatureData); return true; } #endregion #region RSA 签名验证 public bool SignatureDeformatter(string p_strKeyPublic, byte[] HashbyteDeformatter, byte[] DeformatterData) { System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的时候HASH算法为MD5 RSADeformatter.SetHashAlgorithm("MD5"); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } public bool SignatureDeformatter(string p_strKeyPublic, string p_strHashbyteDeformatter, byte[] DeformatterData) { byte[] HashbyteDeformatter; HashbyteDeformatter = Convert.FromBase64String(p_strHashbyteDeformatter); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的时候HASH算法为MD5 RSADeformatter.SetHashAlgorithm("MD5"); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } public bool SignatureDeformatter(string p_strKeyPublic, byte[] HashbyteDeformatter, string p_strDeformatterData) { byte[] DeformatterData; System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的时候HASH算法为MD5 RSADeformatter.SetHashAlgorithm("MD5"); DeformatterData = Convert.FromBase64String(p_strDeformatterData); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } public bool SignatureDeformatter(string p_strKeyPublic, string p_strHashbyteDeformatter, string p_strDeformatterData) { byte[] DeformatterData; byte[] HashbyteDeformatter; HashbyteDeformatter = Convert.FromBase64String(p_strHashbyteDeformatter); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(p_strKeyPublic); System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA); //指定解密的时候HASH算法为MD5 RSADeformatter.SetHashAlgorithm("MD5"); DeformatterData = Convert.FromBase64String(p_strDeformatterData); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } #endregion #endregion }
2.3-公钥/私钥
- 公钥：公开的Key
- 私钥：不公开的Key
- 公开加密Key——>保证数据的安全传递
- 公开解密Key——>保证数据的不可抵赖
- C#内置实现了公钥加密/私钥解密，如果想要用第三方的DLL-BounccyCastle
四、数字证书
2.1-CA证书
2.2-单边认证https
2.3-双边认证
