加密算法解析:MD5、DES和RAS的工作原理与特点

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摘要

理解什么是对称可逆加密:

原文链接:https://www.cnblogs.com/kimiliucn/p/17607330.html


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?

  1. 防篡改
    1. 源代码管理器
    2. 急速秒传
      1. 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。
  2. 密码保存:防止看到明文
    1. 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)
    2. 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;

加密算法解析:MD5、DES和RAS的工作原理与特点

  1. 防止抵赖,数字签名
    1. 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

加密算法解析:MD5、DES和RAS的工作原理与特点
加密算法解析:MD5、DES和RAS的工作原理与特点

四、数字证书

2.1-CA证书

加密算法解析:MD5、DES和RAS的工作原理与特点

2.2-单边认证https

加密算法解析:MD5、DES和RAS的工作原理与特点

2.3-双边认证

加密算法解析:MD5、DES和RAS的工作原理与特点
加密算法解析:MD5、DES和RAS的工作原理与特点

原文链接:https://www.cnblogs.com/kimiliucn/p/17607330.html