commit code samples

Author: irfanajaffer

Digital Signature/How-to-retrieve-signer-data-from-the-. p7m-files/How-to-retrieve-signer-data-from-the-. p7m-files.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.14.36401.2 d17.14
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "How-to-retrieve-signer-data-from-the-. p7m-files", "How-to-retrieve-signer-data-from-the-. p7m-files\How-to-retrieve-signer-data-from-the-. p7m-files.csproj", "{F0EB3137-9B02-4781-8770-250AAECA4DC6}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{F0EB3137-9B02-4781-8770-250AAECA4DC6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F0EB3137-9B02-4781-8770-250AAECA4DC6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F0EB3137-9B02-4781-8770-250AAECA4DC6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F0EB3137-9B02-4781-8770-250AAECA4DC6}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {4CB798B6-B529-4ED0-8F9E-C5F26579318D}
+	EndGlobalSection
+EndGlobal

Digital Signature/How-to-retrieve-signer-data-from-the-. p7m-files/How-to-retrieve-signer-data-from-the-. p7m-files/Data/XCORE-DocumentoTest.pdf.p7m

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <RootNamespace>How_to_retrieve_signer_data_from_the_._p7m_files</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.Security.Cryptography.Pkcs" Version="9.0.8" />
+  </ItemGroup>
+
+</Project>

Digital Signature/How-to-retrieve-signer-data-from-the-. p7m-files/How-to-retrieve-signer-data-from-the-. p7m-files/How-to-retrieve-signer-data-from-the-. p7m-files.csproj

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+using System.Security.Cryptography;
+using System.Security.Cryptography.Pkcs;
+using System.Security.Cryptography.X509Certificates;
+
+namespace How_to_retrieve_signer_data_from_the_. p7m_files
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            // Load the signed CMS (assumes signedCmsBytes contains the Signed CMS data)
+            byte[] signedCmsBytes = File.ReadAllBytes(Path.GetFullPath("Data/XCORE-DocumentoTest.pdf.p7m"));
+
+            SignedCms signedCms = new SignedCms();
+
+            // Decode the Signed CMS data
+            signedCms.Decode(signedCmsBytes);
+
+            // Verify the signature without considering the certificate chain
+            signedCms.CheckSignature(true);
+
+            // Extract the original content
+            byte[] originalMessage = signedCms.ContentInfo.Content;
+            File.WriteAllBytes(Path.GetFullPath("Data/Decoded.pdf"), originalMessage);
+
+            // Extract signer information
+            foreach (SignerInfo signerInfo in signedCms.SignerInfos)
+            {
+                // Get the signing certificate
+                X509Certificate2 signerCertificate = signerInfo.Certificate;
+
+                // Extract signer's name
+                string signerName = signerCertificate?.Subject ?? "Unknown Signer";
+                Console.WriteLine($"Signer Name: {signerName}");
+
+                // Extract signing date (signing time attribute)
+                Pkcs9SigningTime signingTime = null;
+                foreach (var data in from CryptographicAttributeObject attr in signerInfo.SignedAttributes
+                                     from AsnEncodedData data in attr.Values
+                                     where data is Pkcs9SigningTime
+                                     select data)
+                {
+                    signingTime = (Pkcs9SigningTime)data;
+                    break;
+                }
+
+                if (signingTime != null)
+                {
+                    Console.WriteLine($"Signing Time: {signingTime.SigningTime}");
+                }
+                else
+                {
+                    Console.WriteLine("Signing Time: Not available in the attributes.");
+                }
+            }
+        }
+    }
+
+}