在与建设银行做对接的项目的时候，签名的时候需要用SHA256WithRSA算法，因为只有java版本的代码，所以需要自己改写一版.Net算法代码。
1、证书的生成(OpenSSL)
由于我们对接需要互相认证对方的证书，这里的证书要求是SSL证书，网上有很多安装教程可以参考，这里给大家介绍一种比较好的OpenSSL插件，在我们经常使用的项目管理器Git，在安装的时候已经自带了一个OpenSSL插件，我们可以直接运行这个文件，路径是：“C:\Program Files\Git\mingw64\bin\openssl.exe”，如下图（注：需要使用管理员身份运行）
命令行如下
1 openssl genrsa -des3 -out test.key 2048 //需要输入私钥密码 2 openssl req -new -key test.key -out test.csr 3 openssl x509 -req -in test.csr -out test.cer -signkey test.key -days 7500 //有效时间 4 openssl pkcs12 -export -clcerts -in test.cer -inkey test.key -out test.pfx 5 6 //test.cer为公钥证书，test.pfx为私钥证书
证书如下（test.cer为公钥证书，test.pfx为私钥证书）
2、算法代码
生成好证书就可以写算法代码了，直接上代码。
项目引用： using System.Security.Cryptography;using System.Security.Cryptography.X509Certificates;
1 /// <summary>
2 /// 签名算法--SHA256WithRSA
3 /// </summary>
4 /// <param name="dataStr">配置json</param>
5 /// <param name="keyFile">证书路径</param>
6 /// <param name="password">证书密码</param>
7 /// <returns></returns>
8 public static string Sha256Sign(string dataStr, string keyFile, string password)
9 {
10 using (RSACryptoServiceProvider sha256 = new RSACryptoServiceProvider())
11 {
12 var privateKey = GetPrivateKey(keyFile, password); //获取私钥
13 byte[] dataInBytes = DafaultEncoding.GetBytes(dataStr);
14 sha256.FromXmlString(privateKey);
15 byte[] inArray = sha256.SignData(dataInBytes, CryptoConfig.MapNameToOID("SHA256"));
16 string sign = Convert.ToBase64String(inArray);
17 return sign;
18 }
19 }
1 /// <summary>
2 /// 获取私钥
3 /// </summary>
4 /// <param name="path">文件路径</param>
5 /// <param name="password">文件秘钥</param>
6 /// <returns></returns>
7 public static string GetPrivateKey(string path, string password)
8 {
9 try
10 {
11 X509Certificate2 cert = new X509Certificate2(path, password, X509KeyStorageFlags.Exportable | X509KeyStorageFlags.PersistKeySet);
12 return cert.PrivateKey.ToXmlString(true);
13 }
14 catch
15 {
16 return "";
17 }
18 }
3、发签名和数据
1 public static string SendPostRequestJson(string url, string appId, string jsonData,string version, string tenancyId,string passWord, Encoding encoding)
2 {
3 if (string.IsNullOrEmpty(url))
4 throw new ArgumentNullException("url");
5
6 if (encoding == null)
7 encoding = Encoding.UTF8;
8
9 //var dataString = string.Join("&", data.Select(pattern => pattern.Key + "=" + pattern.Value));
10
11 var sign = SignHelper.Sha256Sign(jsonData, "E:/1-trunk/CCB.JobService/CcbApi/files/test.pfx", passWord);
12
13 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
14 request.Method = "POST";
15 request.ContentType = "application/json; charset=" + encoding.WebName;
16 request.Timeout = 60000;
17 request.UserAgent = "IIS";
18 request.Headers.Add("C-Signature", sign);
19 request.Headers.Add("C-App-Id", appId);
20 request.Headers.Add("C-Business-Id", SignHelper.GetBussinessId(appId));
21 request.Headers.Add("C-Timestamp", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"));
22 request.Headers.Add("version", version);
23 request.Headers.Add("C-Tenancy-Id", tenancyId);
24 if (jsonData != null)
25 {
26 byte[] buffer = encoding.GetBytes(jsonData);
27 string json = Convert.ToBase64String(buffer);
28
29 byte[] buffer1 = encoding.GetBytes(json);
30
31 using (Stream stream = request.GetRequestStream())
32 {
33 stream.Write(buffer1, 0, buffer1.Length);
34 }
35 }
36
37 using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
38 {
39 return ReadResponse(response);
40 }
41 }
42
43 /// <summary>
44 /// 读取响应内容。
45 /// </summary>
46 /// <param name="response"></param>
47 /// <returns></returns>
48 private static string ReadResponse(HttpWebResponse response)
49 {
50 if (response == null) return string.Empty;
51 Stream strem = null;
52 if (response.Headers["Content-Encoding"] == "gzip")
53 strem = new GZipStream(response.GetResponseStream(), CompressionMode.Decompress);
54 else
55 strem = response.GetResponseStream();
56
57 if (strem == null) return string.Empty;
58 using (StreamReader reader = new StreamReader(strem))
59 {
60 return reader.ReadToEnd();
61 }
62 }
4、通用接口
1 /// <summary>
2 /// 通用接口
3 /// </summary>
4 /// <typeparam name="T">返回数据实体</typeparam>
5 /// <param name="jsonDate">要传输的参数json字符串</param>
6 /// <param name="url">接口URL</param>
7 /// <returns>响应数据</returns>
8 private static ResponseBase<T> InvokApi<T>(string jsonDate, string url)
9 {
10 try
11 {
12 url = CcbUrl + url;
13 var result = HttpWebRequestHelper.SendPostRequestJson(url, AppId, jsonDate, Version, TenancyId, PassWord, Encoding.UTF8);
14 if (!string.IsNullOrEmpty(result))
15 {
16 result = DecodeBase64(Encoding.UTF8, result);
17 }
18 var res = JsonConvert.DeserializeObject<ResponseBase<T>>(result);
19 if (res.Status != "00")
20 {
21 LogHelper.Log(DateTime.Now + url + ":调用建设银行接口：" + jsonDate);
22 LogHelper.Log(DateTime.Now + ": 调用建设银行返回：" + JsonConvert.SerializeObject(result));
23 }
24
25 return res;
26 }
27 catch (Exception e)
28 {
29 return new ResponseBase<T>();
30 }
31
32 }
over。。