C# 加签 验签 公钥 私钥 RSA数字签名

* RSA加密解密：私钥解密，公钥加密。

 * RSA数字签名-俗称加签验签：私钥加签，公钥验签。 

java的公钥私钥是一串字符串,.net 公钥私钥是一串XML格式字符串,两者格式不是一致的，需要转换一下才能使用，具体请参考

JAVA和NET RSA密钥格式相互转换（公钥，私钥）

 

使用的命名空间:

using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates; 

                 //初始化时生成公钥和私钥
                 RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
                 string privateKey = provider.ToXmlString(true);//生成私钥
                 string publicKey = provider.ToXmlString(false);//生成公钥

加签算法 和 验签算法 必须一致，举栗加签使用的是MD5算法那么验签也必须是MD5算法，不然就会验签失败。栗子中使用的是SHA256算法，对应JAVA的SHA256withRSA算法。

加签:

             /// 

             /// 生成签名
             /// 
             /// 需签名的数据
             /// 私钥
             /// 编码格式 默认utf-8
             /// 签名后的值
             public static string Signature(string str, string privateKey, string encoding)
             {                
                 //SHA256withRSA
                 //根据需要加签时的哈希算法转化成对应的hash字符节
                 //byte[] bt = Encoding.GetEncoding("utf-8").GetBytes(str);
                 byte[] bt = Encoding.GetEncoding(encoding).GetBytes(str);               
                 var sha256 = new SHA256CryptoServiceProvider();
                 byte[] rgbHash = sha256.ComputeHash(bt);

                 RSACryptoServiceProvider key = new RSACryptoServiceProvider();
                 key.FromXmlString(privateKey);
                 RSAPKCS1SignatureFormatter formatter = new RSAPKCS1SignatureFormatter(key);
                 formatter.SetHashAlgorithm("SHA256");//此处是你需要加签的hash算法，需要和上边你计算的hash值的算法一致，不然会报错。
                 byte[] inArray = formatter.CreateSignature(rgbHash);
                 return Convert.ToBase64String(inArray);
             }

公钥验签：

             /// 

             /// 签名验证
             /// 
             /// 待验证的字符串
             /// 加签之后的字符串
             /// 公钥
             /// 编码格式
             /// 签名是否符合
             public static bool SignCheck(string str, string sign, string publicKey, string encoding)
             {
                 try
                 {
                     //byte[] bt = Encoding.GetEncoding("utf-8").GetBytes(str);
                     byte[] bt = Encoding.GetEncoding(encoding).GetBytes(str);
                     var sha256 = new SHA256CryptoServiceProvider();
                     byte[] rgbHash = sha256.ComputeHash(bt);

                     RSACryptoServiceProvider key = new RSACryptoServiceProvider();
                     key.FromXmlString(publicKey);
                     RSAPKCS1SignatureDeformatter deformatter = new RSAPKCS1SignatureDeformatter(key);
                     deformatter.SetHashAlgorithm("SHA256");
                     byte[] rgbSignature = Convert.FromBase64String(sign);
                     if (deformatter.VerifySignature(rgbHash, rgbSignature))
                     {
                         return true;
                     }
                     return false;
                 }
                 catch
                 {
                     return false;
                 }
             }

.cer证书信息 Base64编码 字符串验签：

             /// 

             /// 验签demo
             /// 待验证的字符串
             /// 加签之后的字符串
             /// 
             /// 
             public static void VerifyDataDemo(string Data,string SignData)
             {
                 //加签原文
                 //string Data = "2100040001401529c913701003072941546SwitchFeeInquiry{\"vesselCName\":\"正利洛杉矶\",\"vesselEName\":\"APL LOS ANGELES\",\"voyageNo\":\"0KR44E\",\"billNo\":\"AJKQDAS44E0360\",\"shippingAgencyCode\":\"91370220756929610P\",\"companyCode\":\"913701003072941546\",\"companyName\":\"山东汇贸电子口岸有限公司\",\"remark\":null}";
                 //.cer证书信息 证书导出编码Base64格式 读取证书的Base64编码
                 string certInfoStr = "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";
                 //签名字符串                 
                 //string SignData = "sgvPVzfjBHEpiMFX2vGg2cr/4B7J6FPcLKVKivICSLUAqDvjanbxLKctHlfzYkIfAEEl2OWC/S3ZF2b/ALgeAxsz16MopV2AGXUmakKqUz8wCPSFtZjgjXQzgx49FU2wcXduh4quLD1xhDiW2gMm0ehN2rJ40Ny4zAlEiXCFlGrmfIHlME91AosS/nI9WG3tNIBr7WNHfnjsS2CplXvl5v8Wp3ZZnPtn5cyyXwV4++z5s3k2T9NVx1CJfgkNB03cajPiO7Cc150eSl/YEkN/iZt1ITp1QLuiI5qjKwWaWzOM7G9fmvasoqKc4QqrabmrOucn6sL2QIcj1+ptTltrOA==";

                 X509Certificate2 X509 = new X509Certificate2(Encoding.UTF8.GetBytes(certInfoStr));
                 //string publickey = X509.PublicKey.Key.ToXmlString(false);
                 RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)X509.PublicKey.Key;

                 using (var sha256 = new SHA256CryptoServiceProvider())
                 {                     
                     bool result = rsa.VerifyData(Encoding.UTF8.GetBytes(Data), sha256, Convert.FromBase64String(SignData));
                     Console.WriteLine("验签结果" + result);
                     Console.ReadKey();
                 }
             }