C#实现RSA加密与解密、签名与认证
2015-09-22 13:25
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一、RSA简介
RSA公钥加密算法是1977年由Ron Rivest、Adi Shamirh和LenAdleman在(美国麻省理工学院)开发的。RSA取名来自开发他们三者的名字。RSA是目前最有影响力的公钥加密算法,它能够抵抗到目前为止已知的所有密码攻击,已被ISO推荐为公钥数据加密标准。RSA算法基于一个十分简单的数论事实:将两个大素数相乘十分容易,但那时想要对其乘积进行因式分解却极其困难,因此可以将乘积公开作为加密密钥。RSA算法是第一个能同时用于加密和数字签名的算法,也易于理解和操作。RSA是被研究得最广泛的公钥算法,从提出到现在已近二十年,经历了各种攻击的考验,逐渐为人们接受,普遍认为是目前最优秀的公钥方案之一。RSA的安全性依赖于大数的因子分解,但并没有从理论上证明破译RSA的难度与大数分解难度等价。即RSA的重大缺陷是无法从理论上把握它的保密性能如何,而且密码学界多数人士倾向于因子分解不是NPC问题。
RSA的缺点主要有:
A)产生密钥很麻烦,受到素数产生技术的限制,因而难以做到一次一密。
B)分组长度太大,为保证安全性,n 至少也要 600bits以上,使运算代价很高,尤其是速度较慢,较对称密码算法慢几个数量级;且随着大数分解技术的发展,这个长度还在增加,不利于数据格式的标准化。目前,SET(Secure Electronic Transaction)协议中要求CA采用2048bits长的密钥,其他实体使用1024比特的密钥。
C)RSA密钥长度随着保密级别提高,增加很快。下表列出了对同一安全级别所对应的密钥长度。
这种算法1978年就出现了,它是第一个既能用于数据加密也能用于数字签名的算法。它易于理解和操作,也很流行。算法的名字以发明者的名字命名:Ron Rivest,
AdiShamir 和Leonard Adleman。早在1973年,英国国家通信总局的数学家Clifford Cocks就发现了类似的算法。但是他的发现被列为绝密,直到1998年才公诸于世。
RSA算法是一种非对称密码算法,所谓非对称,就是指该算法需要一对密钥,使用其中一个加密,则需要用另一个才能解密。
RSA的算法涉及三个参数,n、e1、e2。
其中,n是两个大质数p、q的积,n的二进制表示时所占用的位数,就是所谓的密钥长度。
e1和e2是一对相关的值,e1可以任意取,但要求e1与(p-1)*(q-1)互质;再选择e2,要求(e2*e1)mod((p-1)*(q-1))=1。
(n及e1),(n及e2)就是密钥对。
RSA加解密的算法完全相同,设A为明文,B为密文,则:A=B^e1 mod n;B=A^e2 mod n;
e1和e2可以互换使用,即:
A=B^e2 mod n;B=A^e1 mod n;
二、MD5加密介绍
参考:http://blog.csdn.net/wonsoft/article/details/5913572MD5的全称是message-digest algorithm 5(信息-摘要算法,在90年代初由mit laboratory for computer science和rsa data security inc的ronald l. rivest开发出来, 经md2、md3和md4发展而来。
MD5具有很好的安全性(因为它具有不可逆的特征,加过密的密文经过解密后和加密前的东东相同的可能性极小)
public string GetStrMd5(string ConvertString) { string strBodyBase64 = Convert.ToBase64String(Encoding.UTF8.GetBytes(ConvertString)); string t2=System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(strBodyBase64, "MD5").ToUpper(); return t2; }
三、C#对PKCS#8编码的RSA私钥进行签名
对MD5加密后的长度为32的密文进行PKCS8的RSA签名的方法:/// <summary> /// 对MD5加密后的长度为32的密文进行签名 /// </summary> /// <param name="strPrivateKey">私钥</param> /// <param name="strContent">MD5加密后的密文</param> /// <returns></returns> public string SignatureFormatter(string strPrivateKey, string strContent) { byte[] btContent = Encoding.UTF8.GetBytes(strContent); byte[] hv = MD5.Create().ComputeHash(btContent); RSACryptoServiceProvider rsp = new RSACryptoServiceProvider(); rsp.FromXmlString(strPrivateKey); RSAPKCS1SignatureFormatter rf = new RSAPKCS1SignatureFormatter(rsp); rf.SetHashAlgorithm("MD5"); byte[] signature = rf.CreateSignature(hv); return Convert.ToBase64String(signature); }
四、C#实现RSA加密与解密、签名与认证常用方法
1.RSA加密解密:(1)获取密钥,这里是产生密钥,实际应用中可以从各种存储介质上读取密钥 (2)加密 (3)解密
2.RSA签名和验证
(1)获取密钥,这里是产生密钥,实际应用中可以从各种存储介质上读取密钥 (2)获取待签名的Hash码 (3)获取签名的字符串 (4)验证
3.公钥与私钥的理解:
(1)私钥用来进行解密和签名,是给自己用的。
(2)公钥由本人公开,用于加密和验证签名,是给别人用的。
(3)当该用户发送文件时,用私钥签名,别人用他给的公钥验证签名,可以保证该信息是由他发送的。当该用户接受文件时,别人用他的公钥加密,他用私钥解密,可以保证该信息只能由他接收到。
using System.Security.Cryptography; class RSACryption { #region RSA 加密解密 #region RSA 的密钥产生 /// <summary> /// RSA产生密钥 /// </summary> /// <param name="xmlKeys">私钥</param> /// <param name="xmlPublicKey">公钥</param> public void RSAKey(out string xmlKeys, out string xmlPublicKey) { try { System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); xmlKeys = rsa.ToXmlString(true); xmlPublicKey = rsa.ToXmlString(false); } catch (Exception ex) { throw ex; } } #endregion #region RSA加密函数 //############################################################################## //RSA 方式加密 //KEY必须是XML的形式,返回的是字符串 //该加密方式有长度限制的! //############################################################################## /// <summary> /// RSA的加密函数 /// </summary> /// <param name="xmlPublicKey">公钥</param> /// <param name="encryptString">待加密的字符串</param> /// <returns></returns> public string RSAEncrypt(string xmlPublicKey, string encryptString) { try { byte[] PlainTextBArray; byte[] CypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); PlainTextBArray = (new UnicodeEncoding()).GetBytes(encryptString); CypherTextBArray = rsa.Encrypt(PlainTextBArray, false); Result = Convert.ToBase64String(CypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA的加密函数 /// </summary> /// <param name="xmlPublicKey">公钥</param> /// <param name="EncryptString">待加密的字节数组</param> /// <returns></returns> public string RSAEncrypt(string xmlPublicKey, byte[] EncryptString) { try { byte[] CypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); CypherTextBArray = rsa.Encrypt(EncryptString, false); Result = Convert.ToBase64String(CypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } #endregion #region RSA的解密函数 /// <summary> /// RSA的解密函数 /// </summary> /// <param name="xmlPrivateKey">私钥</param> /// <param name="decryptString">待解密的字符串</param> /// <returns></returns> public string RSADecrypt(string xmlPrivateKey, string decryptString) { try { byte[] PlainTextBArray; byte[] DypherTextBArray; string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPrivateKey); PlainTextBArray = Convert.FromBase64String(decryptString); DypherTextBArray = rsa.Decrypt(PlainTextBArray, false); Result = (new UnicodeEncoding()).GetString(DypherTextBArray); return Result; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA的解密函数 /// </summary> /// <param name="xmlPrivateKey">私钥</param> /// <param name="DecryptString">待解密的字节数组</param> /// <returns></returns> public string RSADecrypt(string xmlPrivateKey, byte[] DecryptString) { try { 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; } catch (Exception ex) { throw ex; } } #endregion #endregion #region RSA数字签名 #region 获取Hash描述表 /// <summary> /// 获取Hash描述表 /// </summary> /// <param name="strSource">待签名的字符串</param> /// <param name="HashData">Hash描述</param> /// <returns></returns> public bool GetHash(string strSource, ref byte[] HashData) { try { byte[] Buffer; System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5"); Buffer = System.Text.Encoding.GetEncoding("GB2312").GetBytes(strSource); HashData = MD5.ComputeHash(Buffer); return true; } catch (Exception ex) { throw ex; } } /// <summary> /// 获取Hash描述表 /// </summary> /// <param name="strSource">待签名的字符串</param> /// <param name="strHashData">Hash描述</param> /// <returns></returns> public bool GetHash(string strSource, ref string strHashData) { try { //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(strSource); HashData = MD5.ComputeHash(Buffer); strHashData = Convert.ToBase64String(HashData); return true; } catch (Exception ex) { throw ex; } } /// <summary> /// 获取Hash描述表 /// </summary> /// <param name="objFile">待签名的文件</param> /// <param name="HashData">Hash描述</param> /// <returns></returns> public bool GetHash(System.IO.FileStream objFile, ref byte[] HashData) { try { //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; } catch (Exception ex) { throw ex; } } /// <summary> /// 获取Hash描述表 /// </summary> /// <param name="objFile">待签名的文件</param> /// <param name="strHashData">Hash描述</param> /// <returns></returns> public bool GetHash(System.IO.FileStream objFile, ref string strHashData) { try { //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; } catch (Exception ex) { throw ex; } } #endregion #region RSA签名 /// <summary> /// RSA签名 /// </summary> /// <param name="strKeyPrivate">私钥</param> /// <param name="HashbyteSignature">待签名Hash描述</param> /// <param name="EncryptedSignatureData">签名后的结果</param> /// <returns></returns> public bool SignatureFormatter(string strKeyPrivate, byte[] HashbyteSignature, ref byte[] EncryptedSignatureData) { try { System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA签名 /// </summary> /// <param name="strKeyPrivate">私钥</param> /// <param name="HashbyteSignature">待签名Hash描述</param> /// <param name="m_strEncryptedSignatureData">签名后的结果</param> /// <returns></returns> public bool SignatureFormatter(string strKeyPrivate, byte[] HashbyteSignature, ref string strEncryptedSignatureData) { try { byte[] EncryptedSignatureData; System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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); strEncryptedSignatureData = Convert.ToBase64String(EncryptedSignatureData); return true; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA签名 /// </summary> /// <param name="strKeyPrivate">私钥</param> /// <param name="strHashbyteSignature">待签名Hash描述</param> /// <param name="EncryptedSignatureData">签名后的结果</param> /// <returns></returns> public bool SignatureFormatter(string strKeyPrivate, string strHashbyteSignature, ref byte[] EncryptedSignatureData) { try { byte[] HashbyteSignature; HashbyteSignature = Convert.FromBase64String(strHashbyteSignature); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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; } catch (Exception ex) { throw ex; } } /// <summary> /// RSA签名 /// </summary> /// <param name="strKeyPrivate">私钥</param> /// <param name="strHashbyteSignature">待签名Hash描述</param> /// <param name="strEncryptedSignatureData">签名后的结果</param> /// <returns></returns> public bool SignatureFormatter(string strKeyPrivate, string strHashbyteSignature, ref string strEncryptedSignatureData) { try { byte[] HashbyteSignature; byte[] EncryptedSignatureData; HashbyteSignature = Convert.FromBase64String(strHashbyteSignature); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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); strEncryptedSignatureData = Convert.ToBase64String(EncryptedSignatureData); return true; } catch (Exception ex) { throw ex; } } #endregion #region RSA 签名验证 /// <summary> /// RSA签名验证 /// </summary> /// <param name="strKeyPublic">公钥</param> /// <param name="HashbyteDeformatter">Hash描述</param> /// <param name="DeformatterData">签名后的结果</param> /// <returns></returns> public bool SignatureDeformatter(string strKeyPublic, byte[] HashbyteDeformatter, byte[] DeformatterData) { try { System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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; } } catch (Exception ex) { throw ex; } } /// <summary> /// RSA签名验证 /// </summary> /// <param name="strKeyPublic">公钥</param> /// <param name="strHashbyteDeformatter">Hash描述</param> /// <param name="DeformatterData">签名后的结果</param> /// <returns></returns> public bool SignatureDeformatter(string strKeyPublic, string strHashbyteDeformatter, byte[] DeformatterData) { try { byte[] HashbyteDeformatter; HashbyteDeformatter = Convert.FromBase64String(strHashbyteDeformatter); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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; } } catch (Exception ex) { throw ex; } } /// <summary> /// RSA签名验证 /// </summary> /// <param name="strKeyPublic">公钥</param> /// <param name="HashbyteDeformatter">Hash描述</param> /// <param name="strDeformatterData">签名后的结果</param> /// <returns></returns> public bool SignatureDeformatter(string strKeyPublic, byte[] HashbyteDeformatter, string strDeformatterData) { try { byte[] DeformatterData; System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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(strDeformatterData); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } catch (Exception ex) { throw ex; } } /// <summary> /// RSA签名验证 /// </summary> /// <param name="strKeyPublic">公钥</param> /// <param name="strHashbyteDeformatter">Hash描述</param> /// <param name="strDeformatterData">签名后的结果</param> /// <returns></returns> public bool SignatureDeformatter(string strKeyPublic, string strHashbyteDeformatter, string strDeformatterData) { try { byte[] DeformatterData; byte[] HashbyteDeformatter; HashbyteDeformatter = Convert.FromBase64String(strHashbyteDeformatter); System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); RSA.FromXmlString(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(strDeformatterData); if (RSADeformatter.VerifySignature(HashbyteDeformatter, DeformatterData)) { return true; } else { return false; } } catch (Exception ex) { throw ex; } } #endregion #endregion }
参考网站:
http://www.cnblogs.com/linzheng/archive/2011/02/20/1959123.html http://www.cnblogs.com/sydeveloper/archive/2012/08/11/2633624.html http://codego.net/126956/
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