(.NET Core C#) Duplicate Java Secure Token Creation

Demonstrates how to duplicate some Java code that creates an RSA signature to create a base64 token.

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// This requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// This example duplicates the following Java code:

// public X509Certificate2 cert = new X509Certificate2(@"Some path to p12/p12file_name.p12","Password_for_p12"); 
// 
// public string GenerateSignToken(double timeValidityMin){ 
//   string equalsSign = ":="; 
//   string timeCreated = DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ss.fffzzz"); 
//   string tokenTimeInfo = "validityTimeMinutes" + equalsSign + timeValidityMin + ";"+"timeCreated" + equalsSign + timeCreated; 
//   string signature = SignData(tokenTimeInfo); 
//   string secureToken = tokenTimeInfo + ";" + "signature" + equalsSign + signature; 
//   return Base64UrlEncode(secureToken); 
// } 
//  
// public string SignData(string stringToSign){ 
//   byte[] dataToSign = Encoding.UTF8.GetBytes(stringToSign); 
//   RSACryptoServiceProvider privKey = (RSACryptoServiceProvider)cert.PrivateKey; 
//   CspKeyContainerInfo containerInfo = new RSACryptoServiceProvider().CspKeyContainerInfo; 
//   CspParameters cspparams = new CspParameters(containerInfo.ProviderType, containerInfo.ProviderName, privKey.CspKeyContainerInfo.KeyContainerName); 
//   privKey = new RSACryptoServiceProvider(cspparams); 
//   string id = CryptoConfig.MapNameToOID("SHA256"); 
//   byte[] sign = privKey.SignData(dataToSign, id); 
//   bool res = privKey.VerifyData(dataToSign, id, sign); 
//   return Convert.ToBase64String(sign).Replace('+', '-').Replace('/', '_').Replace("=", ""); 
// } 
//  
// private static string Base64UrlEncode(string input){ 
//   var inputBytes = Encoding.UTF8.GetBytes(input); 
//   return Convert.ToBase64String(inputBytes).Replace('+', '-').Replace('/', '_').Replace("=", ""); 
// } 

bool success;

Chilkat.CkDateTime dt = new Chilkat.CkDateTime();
dt.SetFromCurrentSystemTime();
string timeCreated = dt.GetAsTimestamp(true);

// Such as 2019-04-01T19:35:44-05:00
Debug.WriteLine(timeCreated);

Chilkat.StringBuilder sbToken = new Chilkat.StringBuilder();
sbToken.Append("validityTimeMinutes:=10.0;timeCreated:=");
sbToken.Append(timeCreated);

Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadPfxFile("Some path to p12/p12file_name.p12","Password_for_p12");
if (success != true) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

Chilkat.Rsa rsa = new Chilkat.Rsa();
success = rsa.SetX509Cert(cert,true);
if (success != true) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

rsa.EncodingMode = "base64url";

string signature = rsa.SignStringENC(sbToken.GetAsString(),"sha256");
if (rsa.LastMethodSuccess == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

sbToken.Append(";signature:=");
sbToken.Append(signature);

// Base64URL encode the result
sbToken.Encode("base64url","utf-8");
string token = sbToken.GetAsString();

Debug.WriteLine(token);