RSA不对称加密，公钥加密私钥解密，私钥加密公钥解密

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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。

.NET提供常用的加密算法类，支持RSA的类是RSACryptoServiceProvider（命名空间：System.Security.Cryptography），但只支持公钥加密，私钥解密。RSACryptoServiceProvider类包括：Modulus、Exponent、P、Q、DP、DQ、InverseQ、D等8个属性，其中Modulus和Exponent就是公钥，Modulus和D就是私钥，RSACryptoServiceProvider类提供导出公钥的方法，也提供导出私钥的方法，但导出的私钥包含上面8个属性，显然要用RSACryptoServiceProvider实现私钥加密公钥是不可行的。

从RSA的原理来看，公钥加密私钥解密和私钥加密公钥解密应该是等价的，在某些情况下，比如共享软件加密，我们需要用私钥加密注册码或注册文件，发给用户，用户用公钥解密注册码或注册文件进行合法性验证。

不对称密钥

.NET Framework 为不对称加密提供了 RSACryptoServiceProvider 和 DSACryptoServiceProvider 类。这些类在您使用默认构造函数创建新实例时创建一个公钥/私钥对。既可以存储不对称密钥以用在多个会话中，也可以只为一个会话生成不对称密钥。公钥可以被广泛地使用，私钥应被严密地保护起来。

每当创建不对称算法类的新实例时，都生成一个公钥/私钥对。创建该类的新实例后，可以用以下两种方法之一提取密钥信息：

ToXMLString 方法，它返回密钥信息的 XML 表示形式。导出密钥--xml形式的字符串
对应的方法：FromXmlString通过 XML 字符串中的密钥信息初始化RSA 对象。导入密钥
ExportParameters 方法，它返回RSAParameters 结构以保存密钥信息。导出密钥--参数形式
ImportParameters导入指定的RSAParameters。（重写RSA.ImportParameters(RSAParameters)。）导入密钥

两个方法都接受布尔值，该值指示是只返回公钥信息还是同时返回公钥和私钥信息。通过使用 ImportParameters 方法，可以将 RSACryptoServiceProvider 类初始化为 RSAParameters 结构的值。

下面的代码示例创建 RSACryptoServiceProvider 类的一个新实例，创建一个公钥/私钥对，并将公钥信息保存在RSAParameters 结构中

//Generate a public/private key pair.
RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
//Save the public key information to an RSAParameters structure.
RSAParameters RSAKeyInfo = RSA.ExportParameters(false);

一、公钥加密私钥解密

/// <summary>
/// 公钥加密，私钥解密
/// </summary>
public class RSAEncryptHelper
{
/// <summary>
/// 将字符串使用base64算法加密
/// </summary>
/// <param name="code_type">编码类型</param>
/// <param name="code">待加密的字符串</param>
/// <returns>加密后的字符串</returns>
public string EncodeBase64(string code_type, string code)
{
string encode = "";
byte[] bytes = Encoding.GetEncoding(code_type).GetBytes(code); //将一组字符编码为一个字节序列.
try
{
encode = Convert.ToBase64String(bytes); //将8位无符号整数数组的子集转换为其等效的,以64为基的数字编码的字符串形式.
}
catch
{
encode = code;
}
return encode;
}
/// <summary>
/// 将字符串使用base64算法解密
/// </summary>
/// <param name="code_type">编码类型</param>
/// <param name="code">已用base64算法加密的字符串</param>
/// <returns>解密后的字符串</returns>
public string DecodeBase64(string code_type, string code)
{
string decode = "";
byte[] bytes = Convert.FromBase64String(code); //将2进制编码转换为8位无符号整数数组.
try
{
decode = Encoding.GetEncoding(code_type).GetString(bytes); //将指定字节数组中的一个字节序列解码为一个字符串。
}
catch
{
decode = code;
}
return decode;
}
/// <summary>
/// 获取本机的MAC地址
/// </summary>
/// <returns></returns>
public static string GetLocalMac()
{
string mac = null;
ManagementObjectSearcher query = new ManagementObjectSearcher("SELECT * FROM Win32_NetworkAdapterConfiguration");
ManagementObjectCollection queryCollection = query.Get();
foreach (ManagementObject mo in queryCollection)
{
if (mo["IPEnabled"].ToString() == "True")
mac = mo["MacAddress"].ToString();
}
return (mac);
}
/// <summary>
/// 得到CPU序列号
/// </summary>
/// <returns></returns>
public static string GetCpuID()
{
try
{
//获取CPU序列号代码
string cpuInfo = "";//cpu序列号
ManagementClass mc = new ManagementClass("Win32_Processor");
ManagementObjectCollection moc = mc.GetInstances();
foreach (ManagementObject mo in moc)
{
cpuInfo = mo.Properties["ProcessorId"].Value.ToString();
}
moc = null;
mc = null;
return cpuInfo;
}
catch
{
return "unknow";
}
finally
{
}
}
/// <summary>
/// 生成公私钥
/// </summary>
/// <param name="PrivateKeyPath"></param>
/// <param name="PublicKeyPath"></param>
public void RSAKey(string PrivateKeyPath, string PublicKeyPath)
{
try
{
RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
this.CreatePrivateKeyXML(PrivateKeyPath, provider.ToXmlString(true));
this.CreatePublicKeyXML(PublicKeyPath, provider.ToXmlString(false));
}
catch (Exception exception)
{
throw exception;
}
}
/// <summary>
/// 对原始数据进行MD5加密
/// </summary>
/// <param name="m_strSource">待加密数据</param>
/// <returns>返回机密后的数据</returns>
public string GetHash(string m_strSource)
{
HashAlgorithm algorithm = HashAlgorithm.Create("MD5");
byte[] bytes = Encoding.GetEncoding("GB2312").GetBytes(m_strSource);
byte[] inArray = algorithm.ComputeHash(bytes);
return Convert.ToBase64String(inArray);
}
/// <summary>
/// RSA加密
/// </summary>
/// <param name="xmlPublicKey">公钥</param>
/// <param name="m_strEncryptString">MD5加密后的数据</param>
/// <returns>RSA公钥加密后的数据</returns>
public string RSAEncrypt(string xmlPublicKey, string m_strEncryptString)
{
string str2;
try
{
RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
provider.FromXmlString(xmlPublicKey);
byte[] bytes = new UnicodeEncoding().GetBytes(m_strEncryptString);
str2 = Convert.ToBase64String(provider.Encrypt(bytes, false));
}
catch (Exception exception)
{
throw exception;
}
return str2;
}
/// <summary>
/// RSA解密
/// </summary>
/// <param name="xmlPrivateKey">私钥</param>
/// <param name="m_strDecryptString">待解密的数据</param>
/// <returns>解密后的结果</returns>
public string RSADecrypt(string xmlPrivateKey, string m_strDecryptString)
{
string str2;
try
{
RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
provider.FromXmlString(xmlPrivateKey);
byte[] rgb = Convert.FromBase64String(m_strDecryptString);
byte[] buffer2 = provider.Decrypt(rgb, false);
str2 = new UnicodeEncoding().GetString(buffer2);
}
catch (Exception exception)
{
throw exception;
}
return str2;
}
/// <summary>
/// 对MD5加密后的密文进行签名
/// </summary>
/// <param name="p_strKeyPrivate">私钥</param>
/// <param name="m_strHashbyteSignature">MD5加密后的密文</param>
/// <returns></returns>
public string SignatureFormatter(string p_strKeyPrivate, string m_strHashbyteSignature)
{
byte[] rgbHash = Convert.FromBase64String(m_strHashbyteSignature);
RSACryptoServiceProvider key = new RSACryptoServiceProvider();
key.FromXmlString(p_strKeyPrivate);
RSAPKCS1SignatureFormatter formatter = new RSAPKCS1SignatureFormatter(key);
formatter.SetHashAlgorithm("MD5");
byte[] inArray = formatter.CreateSignature(rgbHash);
return Convert.ToBase64String(inArray);
}
/// <summary>
/// 签名验证
/// </summary>
/// <param name="p_strKeyPublic">公钥</param>
/// <param name="p_strHashbyteDeformatter">待验证的用户名</param>
/// <param name="p_strDeformatterData">注册码</param>
/// <returns></returns>
public bool SignatureDeformatter(string p_strKeyPublic, string p_strHashbyteDeformatter, string p_strDeformatterData)
{
try
{
byte[] rgbHash = Convert.FromBase64String(p_strHashbyteDeformatter);
RSACryptoServiceProvider key = new RSACryptoServiceProvider();
key.FromXmlString(p_strKeyPublic);
RSAPKCS1SignatureDeformatter deformatter = new RSAPKCS1SignatureDeformatter(key);
deformatter.SetHashAlgorithm("MD5");
byte[] rgbSignature = Convert.FromBase64String(p_strDeformatterData);
if (deformatter.VerifySignature(rgbHash, rgbSignature))
{
return true;
}
return false;
}
catch
{
return false;
}
}
/// <summary>
/// 获取硬盘ID
/// </summary>
/// <returns>硬盘ID</returns>
public string GetHardID()
{
string HDInfo = "";
ManagementClass cimobject1 = new ManagementClass("Win32_DiskDrive");
ManagementObjectCollection moc1 = cimobject1.GetInstances();
foreach (ManagementObject mo in moc1)
{
HDInfo = (string)mo.Properties["Model"].Value;
}
return HDInfo;
}
/// <summary>
/// 读注册表中指定键的值
/// </summary>
/// <param name="key">键名</param>
/// <returns>返回键值</returns>
private string ReadReg(string key)
{
string temp = "";
try
{
RegistryKey myKey = Registry.LocalMachine;
RegistryKey subKey = myKey.OpenSubKey(@"SOFTWARE/JX/Register");
temp = subKey.GetValue(key).ToString();
subKey.Close();
myKey.Close();
return temp;
}
catch (Exception)
{
throw;//可能没有此注册项;
}
}
/// <summary>
/// 创建注册表中指定的键和值
/// </summary>
/// <param name="key">键名</param>
/// <param name="value">键值</param>
private void WriteReg(string key, string value)
{
try
{
RegistryKey rootKey = Registry.LocalMachine.CreateSubKey(@"SOFTWARE/JX/Register");
rootKey.SetValue(key, value);
rootKey.Close();
}
catch (Exception)
{
throw;
}
}
/// <summary>
/// 创建公钥文件
/// </summary>
/// <param name="path"></param>
/// <param name="publickey"></param>
public void CreatePublicKeyXML(string path, string publickey)
{
try
{
FileStream publickeyxml = new FileStream(path, FileMode.Create);
StreamWriter sw = new StreamWriter(publickeyxml);
sw.WriteLine(publickey);
sw.Close();
publickeyxml.Close();
}
catch
{
throw;
}
}
/// <summary>
/// 创建私钥文件
/// </summary>
/// <param name="path"></param>
/// <param name="privatekey"></param>
public void CreatePrivateKeyXML(string path, string privatekey)
{
try
{
FileStream privatekeyxml = new FileStream(path, FileMode.Create);
StreamWriter sw = new StreamWriter(privatekeyxml);
sw.WriteLine(privatekey);
sw.Close();
privatekeyxml.Close();
}
catch
{
throw;
}
}
/// <summary>
/// 读取公钥
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
public string ReadPublicKey(string path)
{
StreamReader reader = new StreamReader(path);
string publickey = reader.ReadToEnd();
reader.Close();
return publickey;
}
/// <summary>
/// 读取私钥
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
public string ReadPrivateKey(string path)
{
StreamReader reader = new StreamReader(path);
string privatekey = reader.ReadToEnd();
reader.Close();
return privatekey;
}
/// <summary>
/// 初始化注册表，程序运行时调用，在调用之前更新公钥xml
/// </summary>
/// <param name="path">公钥路径</param>
public void InitialReg(string path)
{
Registry.LocalMachine.CreateSubKey(@"SOFTWARE/JX/Register");
Random ra = new Random();
string publickey = this.ReadPublicKey(path);
if (Registry.LocalMachine.OpenSubKey(@"SOFTWARE/JX/Register").ValueCount <= 0)
{
this.WriteReg("RegisterRandom", ra.Next(1, 100000).ToString());
this.WriteReg("RegisterPublicKey", publickey);
}
else
{
this.WriteReg("RegisterPublicKey", publickey);
}
}
}

二、私钥加密公钥解密

/// <summary>
/// 非对称RSA加密类可以参考
/// http://www.cnblogs.com/hhh/archive/2011/06/03/2070692.html
/// http://blog.csdn.net/zhilunchen/article/details/2943158
/// http://www.cnblogs.com/yyl8781697/archive/2013/04/28/RSA.html
/// 若是私匙加密则需公钥解密
/// 反正公钥加密私匙来解密
/// 需要BigInteger类来辅助
/// </summary>
public static class RSAHelper
{
/// <summary>
/// RSA的容器可以解密的源字符串长度为 DWKEYSIZE/8-11
/// </summary>
public const int DWKEYSIZE = 1024;
/// <summary>
/// RSA加密的密匙结构公钥和私匙
/// </summary>
//public struct RSAKey
//{
// public string PublicKey { get; set; }
// public string PrivateKey { get; set; }
//}
#region 得到RSA的解谜的密匙对
/// <summary>
/// 得到RSA的解谜的密匙对
/// </summary>
/// <returns></returns>
//public static RSAKey GetRASKey()
//{
// RSACryptoServiceProvider.UseMachineKeyStore = true;
// //声明一个指定大小的RSA容器
// RSACryptoServiceProvider rsaProvider = new RSACryptoServiceProvider(DWKEYSIZE);
// //取得RSA容易里的各种参数
// RSAParameters p = rsaProvider.ExportParameters(true);
// return new RSAKey()
// {
// PublicKey = ComponentKey(p.Exponent, p.Modulus),
// PrivateKey = ComponentKey(p.D, p.Modulus)
// };
//}
#endregion
#region 检查明文的有效性 DWKEYSIZE/8-11 长度之内为有效中英文都算一个字符
/// <summary>
/// 检查明文的有效性 DWKEYSIZE/8-11 长度之内为有效中英文都算一个字符
/// </summary>
/// <param name="source"></param>
/// <returns></returns>
public static bool CheckSourceValidate(string source)
{
return (DWKEYSIZE / 8 - 11) >= source.Length;
}
#endregion
#region 组合解析密匙
/// <summary>
/// 组合成密匙字符串
/// </summary>
/// <param name="b1"></param>
/// <param name="b2"></param>
/// <returns></returns>
public static string ComponentKey(byte[] b1, byte[] b2)
{
List<byte> list = new List<byte>();
//在前端加上第一个数组的长度值这样今后可以根据这个值分别取出来两个数组
list.Add((byte)b1.Length);
list.AddRange(b1);
list.AddRange(b2);
byte[] b = list.ToArray<byte>();
return Convert.ToBase64String(b);
}
/// <summary>
/// 解析密匙
/// </summary>
/// <param name="key">密匙</param>
/// <param name="b1">RSA的相应参数1</param>
/// <param name="b2">RSA的相应参数2</param>
private static void ResolveKey(string key, out byte[] b1, out byte[] b2)
{
//从base64字符串解析成原来的字节数组
byte[] b = Convert.FromBase64String(key);
//初始化参数的数组长度
b1 = new byte[b[0]];
b2 = new byte[b.Length - b[0] - 1];
//将相应位置是值放进相应的数组
for (int n = 1, i = 0, j = 0; n < b.Length; n++)
{
if (n <= b[0])
{
b1[i++] = b[n];
}
else
{
b2[j++] = b[n];
}
}
}
#endregion
#region 字符串加密解密公开方法
/// <summary>
/// 字符串加密
/// </summary>
/// <param name="source">源字符串明文</param>
/// <param name="key">密匙</param>
/// <returns>加密遇到错误将会返回原字符串</returns>
public static string EncryptString(string source, string key)
{
string encryptString = string.Empty;
byte[] d;
byte[] n;
try
{
if (!CheckSourceValidate(source))
{
throw new Exception("source string too long");
}
//解析这个密钥
ResolveKey(key, out d, out n);
BigInteger biN = new BigInteger(n);
BigInteger biD = new BigInteger(d);
encryptString = EncryptString(source, biD, biN);
}
catch
{
encryptString = source;
}
return encryptString;
}
/// <summary>
/// 字符串解密
/// </summary>
/// <param name="encryptString">密文</param>
/// <param name="key">密钥</param>
/// <returns>遇到解密失败将会返回空字符串</returns>
public static string DecryptString(string encryptString, string key)
{
string source = string.Empty;
byte[] e;
byte[] n;
try
{
//解析这个密钥
ResolveKey(key, out e, out n);
BigInteger biE = new BigInteger(e);
BigInteger biN = new BigInteger(n);
source = DecryptString(encryptString, biE, biN);
}
catch
{
}
return source;
}
#endregion
#region 字符串加密解密私有实现加解密的实现方法
/// <summary>
/// 用指定的密匙加密
/// </summary>
/// <param name="source">明文</param>
/// <param name="d">可以是RSACryptoServiceProvider生成的D</param>
/// <param name="n">可以是RSACryptoServiceProvider生成的Modulus</param>
/// <returns>返回密文</returns>
private static string EncryptString(string source, BigInteger d, BigInteger n)
{
int len = source.Length;
int len1 = 0;
int blockLen = 0;
if ((len % 128) == 0)
len1 = len / 128;
else
len1 = len / 128 + 1;
string block = "";
StringBuilder result = new StringBuilder();
for (int i = 0; i < len1; i++)
{
if (len >= 128)
blockLen = 128;
else
blockLen = len;
block = source.Substring(i * 128, blockLen);
byte[] oText = System.Text.Encoding.Default.GetBytes(block);
BigInteger biText = new BigInteger(oText);
BigInteger biEnText = biText.modPow(d, n);
string temp = biEnText.ToHexString();
result.Append(temp).Append("@");
len -= blockLen;
}
return result.ToString().TrimEnd('@');
}
/// <summary>
/// 用指定的密匙加密
/// </summary>
/// <param name="source">密文</param>
/// <param name="e">可以是RSACryptoServiceProvider生成的Exponent</param>
/// <param name="n">可以是RSACryptoServiceProvider生成的Modulus</param>
/// <returns>返回明文</returns>
private static string DecryptString(string encryptString, BigInteger e, BigInteger n)
{
StringBuilder result = new StringBuilder();
string[] strarr1 = encryptString.Split(new char[] { '@' }, StringSplitOptions.RemoveEmptyEntries);
for (int i = 0; i < strarr1.Length; i++)
{
string block = strarr1[i];
BigInteger biText = new BigInteger(block, 16);
BigInteger biEnText = biText.modPow(e, n);
string temp = System.Text.Encoding.Default.GetString(biEnText.getBytes());
result.Append(temp);
}
return result.ToString();
}
#endregion
/// <summary>
/// 将字符串使用base64算法加密
/// </summary>
/// <param name="code_type">编码类型</param>
/// <param name="code">待加密的字符串</param>
/// <returns>加密后的字符串</returns>
public static string EncodeBase64(string code_type, string code)
{
string encode = "";
byte[] bytes = Encoding.GetEncoding(code_type).GetBytes(code); //将一组字符编码为一个字节序列.
try
{
encode = Convert.ToBase64String(bytes); //将8位无符号整数数组的子集转换为其等效的,以64为基的数字编码的字符串形式.
}
catch
{
encode = code;
}
return encode;
}
/// <summary>
/// 将字符串使用base64算法解密
/// </summary>
/// <param name="code_type">编码类型</param>
/// <param name="code">已用base64算法加密的字符串</param>
/// <returns>解密后的字符串</returns>
public static string DecodeBase64(string code_type, string code)
{
string decode = "";
byte[] bytes = Convert.FromBase64String(code); //将2进制编码转换为8位无符号整数数组.
try
{
decode = Encoding.GetEncoding(code_type).GetString(bytes); //将指定字节数组中的一个字节序列解码为一个字符串。
}
catch
{
decode = code;
}
return decode;
}
/// <summary>
/// 读取公钥或私钥
/// </summary>
/// <param name="includePrivateparameters">为True则包含私钥</param>
/// <param name="path">Xml格式保存的完整公/私钥路径</param>
/// <returns>公钥或私钥参数形式 </returns>
public static RSAParameters ReadKey(bool includePrivateparameters,string path)
{
using (StreamReader reader = new StreamReader(path))
{
string publickey = reader.ReadToEnd();
RSACryptoServiceProvider rcp = new RSACryptoServiceProvider();
rcp.FromXmlString(publickey);
return rcp.ExportParameters(includePrivateparameters);
}
}
/// <summary>
/// 获取本机的MAC地址
/// </summary>
/// <returns></returns>
public static string GetLocalMac()
{
string mac = null;
ManagementObjectSearcher query = new ManagementObjectSearcher("SELECT * FROM Win32_NetworkAdapterConfiguration");
ManagementObjectCollection queryCollection = query.Get();
foreach (ManagementObject mo in queryCollection)
{
if (mo["IPEnabled"].ToString() == "True")
mac = mo["MacAddress"].ToString();
}
return (mac);
}
/// <summary>
/// 得到CPU序列号
/// </summary>
/// <returns></returns>
public static string GetCpuID()
{
try
{
//获取CPU序列号代码
string cpuInfo = "";//cpu序列号
ManagementClass mc = new ManagementClass("Win32_Processor");
ManagementObjectCollection moc = mc.GetInstances();
foreach (ManagementObject mo in moc)
{
cpuInfo = mo.Properties["ProcessorId"].Value.ToString();
}
moc = null;
mc = null;
return cpuInfo;
}
catch
{
return "unknow";
}
finally
{
}
}
/// <summary>
/// 获取硬盘ID
/// </summary>
/// <returns>硬盘ID</returns>
public static string GetHardID()
{
string HDInfo = "";
ManagementClass cimobject1 = new ManagementClass("Win32_DiskDrive");
ManagementObjectCollection moc1 = cimobject1.GetInstances();
foreach (ManagementObject mo in moc1)
{
HDInfo = (string)mo.Properties["Model"].Value;
}
return HDInfo;
}
/// <summary>
/// 读注册表中指定键的值
/// </summary>
/// <param name="key">键名</param>
/// <returns>返回键值</returns>
private static string ReadReg(string key)
{
string temp = "";
try
{
RegistryKey myKey = Registry.LocalMachine;
RegistryKey subKey = myKey.OpenSubKey(@"SOFTWARE/JX/Register");
temp = subKey.GetValue(key).ToString();
subKey.Close();
myKey.Close();
return temp;
}
catch (Exception)
{
throw;//可能没有此注册项;
}
}
/// <summary>
/// 创建注册表中指定的键和值
/// </summary>
/// <param name="key">键名</param>
/// <param name="value">键值</param>
private static void WriteReg(string key, string value)
{
try
{
RegistryKey rootKey = Registry.LocalMachine.CreateSubKey(@"SOFTWARE/JX/Register");
rootKey.SetValue(key, value);
rootKey.Close();
}
catch (Exception)
{
throw;
}
}
}