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Added document signing-in #1

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147 changes: 86 additions & 61 deletions DocumentSigner.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,87 +1,112 @@
using System.Security.Cryptography.X509Certificates;
using Microsoft.Extensions.Configuration;
using iTextSharp.text.pdf;
using Org.BouncyCastle.Security;
using X509Certificate = Org.BouncyCastle.X509.X509Certificate;
using iTextSharp.text.pdf.security;
using System.Text;


namespace DesktopDocumentSigner
{
internal class DocumentSigner
{
private string location = "Location";
private const string FIELD_NAME = "Digitally signed";
private string _certificateThumbprint;
private string _encoded_file;
private string _documentName;
private string _location;
private PdfReader _inputPdf;
private readonly iTextSharp.text.Rectangle PAGE_RECT = new iTextSharp.text.Rectangle(375, 565, 575, 715);
private BaseFont _base_font;
private byte[] file;

private MemoryStream SignDocument(byte[] file, string document_name)
public DocumentSigner(string certificateThumbprint, string encodedFile, string documentName, string location)
{
_certificateThumbprint = certificateThumbprint;
_encoded_file = encodedFile;
_documentName = documentName;
_location = location;
file = Convert.FromBase64String(_encoded_file);
_inputPdf = new PdfReader(file);
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
_base_font = BaseFont.CreateFont("OpenSans-Regular.ttf", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
}

X509Certificate2 certificate = GetCertificateFromStore();
if (certificate != null)
public static X509Certificate2? GetCertificateFromStore(string certificateThumbprint)
{
X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
store.Open(OpenFlags.ReadOnly);
var certificate2Collection = store.Certificates.Find(X509FindType.FindByThumbprint, certificateThumbprint, false);
if (certificate2Collection.Count == 0)
{
var arialBaseFont = BaseFont.CreateFont("ArialCE.ttf", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);

IList<X509Certificate> chain = new List<X509Certificate>();
PdfReader inputPdf = new PdfReader(file);
using (MemoryStream signedPdf = new MemoryStream())
return null;
}
else
{
foreach (X509Certificate2 certificate in certificate2Collection)
{
IExternalSignature externalSignature = new X509Certificate2Signature(certificate, "SHA-256");
PdfStamper pdfStamper = PdfStamper.CreateSignature(inputPdf, signedPdf, '\0');
PdfSignatureAppearance signatureAppearance = pdfStamper.SignatureAppearance;
pdfStamper.AcroFields.AddSubstitutionFont(arialBaseFont);
signatureAppearance.Layer2Font = new iTextSharp.text.Font(arialBaseFont, 12f);
signatureAppearance.Location = location;
if (document_name.Contains("DRIVER_CALL"))
if (certificate.HasPrivateKey && certificate.Thumbprint.ToLower() == certificateThumbprint)
{
try
{
signatureAppearance.SetVisibleSignature(new iTextSharp.text.Rectangle(350, 50, 550, 200), inputPdf.NumberOfPages - 1, "Digitally signed");
}
catch (ArgumentException e)
{
return new MemoryStream(file);
}
return certificate;
}
else if (document_name.Contains("ORDER_WITH_EIF"))
{
try
{
signatureAppearance.SetVisibleSignature(new iTextSharp.text.Rectangle(375, 565, 575, 715), 1, "Digitally signed");
}
catch (ArgumentException e)
{
Console.WriteLine($"Dokument {document_name} již byl podepsán, vrácen beze změny ({DateTime.Now}).");
return new MemoryStream(file);
}
}
else
{
try
{
signatureAppearance.SetVisibleSignature(new iTextSharp.text.Rectangle(350, 50, 550, 200), inputPdf.NumberOfPages, "Digitally signed");
}
catch (ArgumentException e)
{
Console.WriteLine($"Dokument {document_name} již byl podepsán, vrácen beze změny ({DateTime.Now}).");
return new MemoryStream(file);
}

}
signatureAppearance.SignatureRenderingMode = PdfSignatureAppearance.RenderingMode.DESCRIPTION;
chain.Add(DotNetUtilities.FromX509Certificate(certificate));
MakeSignature.SignDetached(signatureAppearance, externalSignature, chain, null, null, null, 0, CryptoStandard.CMS);
inputPdf.Close();
pdfStamper.Close();

Console.WriteLine($"Dokument {document_name} byl podepsán ({DateTime.Now}).");
return signedPdf;
}
}
return new MemoryStream();
store.Close();
return null;
}

private int CalculatePage()
{
if (_documentName.Contains("ORDER_WITH_EIF"))
{
return 1;
}
else
{
return _inputPdf.NumberOfPages;
}
}

private X509Certificate2 GetCertificateFromStore()
public SignatureResult SignDocument()
{
throw new NotImplementedException();
X509Certificate2? certificate = GetCertificateFromStore(_certificateThumbprint);
if (certificate != null)
{
string resultText = "";
IList<X509Certificate> chain = new List<X509Certificate>();
MemoryStream signedPdf = new MemoryStream();
IExternalSignature externalSignature = new X509Certificate2Signature(certificate, "SHA-256");
PdfStamper pdfStamper = PdfStamper.CreateSignature(_inputPdf, signedPdf, '\0');
PdfSignatureAppearance signatureAppearance = pdfStamper.SignatureAppearance;
pdfStamper.AcroFields.AddSubstitutionFont(_base_font);
signatureAppearance.Layer2Font = new iTextSharp.text.Font(_base_font, 12f);
signatureAppearance.Location = _location;
try
{
signatureAppearance.SetVisibleSignature(PAGE_RECT, CalculatePage(), FIELD_NAME);
}
catch (ArgumentException e)
{
resultText = $"Dokument {_documentName} již byl podepsán, vrácen beze změny ({DateTime.Now}).";
signedPdf = new MemoryStream(file);
}
signatureAppearance.SignatureRenderingMode = PdfSignatureAppearance.RenderingMode.DESCRIPTION;
chain.Add(DotNetUtilities.FromX509Certificate(certificate));
MakeSignature.SignDetached(signatureAppearance, externalSignature, chain, null, null, null, 0, CryptoStandard.CMS);
_inputPdf.Close();
pdfStamper.Close();
string signedPDF_base64 = Convert.ToBase64String(signedPdf.ToArray());
SignatureResult signatureResult = new SignatureResult{
ResultText = resultText,
SignedDocumentBase64 = signedPDF_base64

};
return signatureResult;
}
else
{
return new SignatureResult{ ResultText = $"Dokument {_documentName} není možné podepsat." };
}
}
}
}
7 changes: 2 additions & 5 deletions MainPage.xaml
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Original file line number Diff line number Diff line change
Expand Up @@ -19,11 +19,6 @@
Style="{StaticResource Headline}"
SemanticProperties.HeadingLevel="Level1" />

<Label
Text="Waiting for Documents"
Style="{StaticResource SubHeadline}"
SemanticProperties.HeadingLevel="Level2" />

<CollectionView
x:Name="LogCollection"
ItemsSource="{Binding LogEntries}"
Expand Down Expand Up @@ -61,8 +56,10 @@

<Button
Text="Save"
x:Name="Save"
FontSize="16"
Padding="10"
Clicked="Save_Clicked"
/>
</HorizontalStackLayout>

Expand Down
162 changes: 159 additions & 3 deletions MainPage.xaml.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,22 +1,178 @@
using System.Collections.ObjectModel;
using System.Net;
using System.Security.Cryptography.X509Certificates;
using System.Text.Json;
using Microsoft.Extensions.Logging;
using Org.BouncyCastle.Bcpg;

namespace DesktopDocumentSigner
{
public partial class MainPage : ContentPage
{
int count = 0;
public ObservableCollection<string> LogEntries { get; set; }
private static string _filePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "settings.json");
private Settings? settings;
private const string _listenOn = "http://127.0.0.1:8080/";
private static HttpListener _httpListener = new HttpListener();

public MainPage()
{
InitializeComponent();
LogEntries = new ObservableCollection<string>
{
"App started",
"No documents detected",
"Ready for new document"
"App started"
};
BindingContext = this;
LoadSettings();
StartHttpServer();
}

private async void StartHttpServer()
{
_httpListener.Prefixes.Add(_listenOn);

try
{
_httpListener.Start();

while (true)
{
var context = await _httpListener.GetContextAsync();
HandleRequest(context);
}
}
catch (Exception ex)
{
Console.WriteLine($"Error: {ex.Message}");
}
}

private void HandleRequest(HttpListenerContext context)
{
try
{
var request = context.Request;
var response = context.Response;
context.Response.Headers.Add("Access-Control-Allow-Origin", "*");
context.Response.Headers.Add("Access-Control-Allow-Methods", "GET, POST");
context.Response.Headers.Add("Access-Control-Allow-Headers", "Content-Type, Authorization");

if (request.HttpMethod == "POST")
{
HandlePostRequest(request, response);
}
else
{
HandleDefaultRequest(response);
}
}
catch (Exception ex)
{
Console.WriteLine($"Error handling request: {ex.Message}");
}
}

private void HandleDefaultRequest(HttpListenerResponse response)
{
string responseString = "Pink OK!";
byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
response.ContentLength64 = buffer.Length;

using (var output = response.OutputStream)
{
output.Write(buffer, 0, buffer.Length);
}

}

private void HandlePostRequest(HttpListenerRequest request, HttpListenerResponse response)
{
try
{
using (var reader = new StreamReader(request.InputStream, request.ContentEncoding))
{
var requestBody = reader.ReadToEnd();
var parsedData = JsonSerializer.Deserialize<Dictionary<string, string>>(requestBody);

if (parsedData is not null && settings is not null)
{
var signedFilesCollection = new Dictionary<string, string>();

foreach (var kvp in parsedData)
{
string documentName = kvp.Key;
string value = kvp.Value;

DocumentSigner documentSigner = new DocumentSigner(settings.CertificateHash, value, documentName, settings.SignatureLocation);
SignatureResult signatureResult = documentSigner.SignDocument();
signedFilesCollection.Add(documentName, signatureResult.SignedDocumentBase64);
LogEntries.Insert(0, signatureResult.ResultText);
}

response.StatusCode = (int)HttpStatusCode.OK;
response.ContentType = "application/json";
var responseJson = JsonSerializer.Serialize(signedFilesCollection);

using (var writer = new StreamWriter(response.OutputStream))
{
writer.Write(responseJson);
}
}
else
{
response.StatusCode = (int)HttpStatusCode.BadRequest;
}
}
}
catch (Exception ex)
{
response.StatusCode = (int)HttpStatusCode.InternalServerError;
using (var writer = new StreamWriter(response.OutputStream))
{
writer.Write(JsonSerializer.Serialize(new { error = ex.Message }));
}
}
}

private void LoadSettings()
{
if (File.Exists(_filePath))
{
var json = File.ReadAllText(_filePath);
settings = JsonSerializer.Deserialize<Settings>(json);

CertificateHashEntry.Text = settings.CertificateHash;
LocationEntry.Text = settings.SignatureLocation;
}
}

private void Save_Clicked(object sender, EventArgs e)
{
var settings = new Settings
{
CertificateHash = CertificateHashEntry.Text,
SignatureLocation = LocationEntry.Text
};

var json = JsonSerializer.Serialize(settings, new JsonSerializerOptions { WriteIndented = true });
X509Certificate2? certificate = DocumentSigner.GetCertificateFromStore(settings.CertificateHash);

if (certificate == null)
{
DisplayAlert("Error", $"Certificate with fingerprint {settings.CertificateHash} was not found.", "OK");
return;
}

try
{
File.WriteAllText(_filePath, json);
LogEntries.Insert(0, "Configuration Saved");
}
catch (Exception ex)
{
DisplayAlert("Error", $"An error occurred while saving settings: {ex.Message}", "OK");
}
}
}

Expand Down
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