(.NET Core C#) Verify a CAdES-BES Signature and Examine Signature Contents

Demonstrates how to validate a .p7m (.p7s) signature and examine the contents of the signature.

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

Chilkat.Crypt2 crypt = new Chilkat.Crypt2();

string outputFile = "qa_output/original.xml";
string inFile = "qa_data/p7m/fattura_signature.xml.p7m";

// Verify the signature and extract the contained file, which in this case is XML.
bool success = crypt.VerifyP7M(inFile,outputFile);
if (success == false) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

Debug.WriteLine("Signature validated.");

// Now let's examine the information about the signature.
Chilkat.JsonObject json = crypt.LastJsonData();
if (crypt.LastMethodSuccess == false) {
    // This should never be the case...
    Debug.WriteLine("No information available.");
    return;
}

json.EmitCompact = false;
Debug.WriteLine(json.Emit());

// Here's an example of the information about the signature:
// {
//   "pkcs7": {
//     "verify": {
//       "certs": [
//         {
//           "issuerCN": "Xyz EU Qualified Certificates CA G1",
//           "serial": "99A28A51AC389999"
//         }
//       ],
//       "useConstructedOctets": true,
//       "digestAlgorithms": [
//         "sha256"
//       ],
//       "signerInfo": [
//         {
//           "cert": {
//             "subjectKeyIdentifier": "5VM4x8AWnXf07yzbXuLtbb0U3yY=",
//             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
//             "digestAlgName": "SHA256"
//           },
//           "signingAlgOid": "1.2.840.113549.1.1.11",
//           "signingAlgName": "RSA-SHA256-PKCSV-1_5",
//           "authAttr": {
//             "1.2.840.113549.1.9.3": {
//               "name": "contentType",
//               "oid": "1.2.840.113549.1.7.1"
//             },
//             "1.2.840.113549.1.9.5": {
//               "name": "signingTime",
//               "utctime": "190901152340Z"
//             },
//             "1.2.840.113549.1.9.4": {
//               "name": "messageDigest",
//               "digest": "y+gd/zAQK33A//HInhaZba7w1fUJleV9AHbP1Ntx6U0="
//             },
//             "1.2.840.113549.1.9.16.2.47": {
//               "name": "signingCertificateV2",
//               "der": "MIH4MI..w4vv0="
//             }
//           }
//         }
//       ]
//     }
//   }
// }

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

Chilkat.DtObj authAttrSigningTimeUtctime = new Chilkat.DtObj();
string issuerCN;
string serial;
string strVal;
string certSubjectKeyIdentifier;
string certDigestAlgOid;
string certDigestAlgName;
string signingAlgOid;
string signingAlgName;
string authAttrContentTypeName;
string authAttrContentTypeOid;
string authAttrSigningTimeName;
string authAttrMessageDigestName;
string authAttrMessageDigestDigest;
string authAttrSigningCertificateV2Name;
string authAttrSigningCertificateV2Der;

int i = 0;
int count_i = json.SizeOfArray("pkcs7.verify.certs");
while (i < count_i) {
    json.I = i;
    issuerCN = json.StringOf("pkcs7.verify.certs[i].issuerCN");
    serial = json.StringOf("pkcs7.verify.certs[i].serial");
    i = i + 1;
}

i = 0;
count_i = json.SizeOfArray("pkcs7.verify.digestAlgorithms");
while (i < count_i) {
    json.I = i;
    strVal = json.StringOf("pkcs7.verify.digestAlgorithms[i]");
    i = i + 1;
}

i = 0;
count_i = json.SizeOfArray("pkcs7.verify.signerInfo");
while (i < count_i) {
    json.I = i;
    certSubjectKeyIdentifier = json.StringOf("pkcs7.verify.signerInfo[i].cert.subjectKeyIdentifier");
    certDigestAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid");
    certDigestAlgName = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName");
    signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid");
    signingAlgName = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgName");
    authAttrContentTypeName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".name");
    authAttrContentTypeOid = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.3\".oid");
    authAttrSigningTimeName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".name");
    json.DtOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.5\".utctime",false,authAttrSigningTimeUtctime);
    authAttrMessageDigestName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".name");
    authAttrMessageDigestDigest = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.4\".digest");
    authAttrSigningCertificateV2Name = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.16.2.47\".name");
    authAttrSigningCertificateV2Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.16.2.47\".der");
    i = i + 1;
}