(C# UWP/WinRT) Verify and Unwrap S/MIME, and get Information about CMS Signature

Demonstrates calling the Verify method to verify and unwrap S/MIME. The MIME is restored to the original structure that it would have originally had prior to signing. The Verify method works with both detached signatures, as well as opaque/attached signatures.

Calls LastJsonData to get information about the signature(s) that were verified.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

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

Chilkat.Mime mime = new Chilkat.Mime();

// Load the signed MIME from a file...
bool success = mime.LoadMimeFile("qa_data/mime/detached_sig.eml");
if (success == false) {
    Debug.WriteLine(mime.LastErrorText);
    return;
}

// Verify the S/MIME and restore the MIME
// to the structure/content it had prior to signing.
bool verified = mime.Verify();
if (verified == false) {
    Debug.WriteLine(mime.LastErrorText);
    return;
}

// Examine the details of what was verified.
Chilkat.JsonObject json = mime.LastJsonData();
json.EmitCompact = false;
Debug.WriteLine(json.Emit());

// The code to parse the following JSON (i.e. extract desired information) is shown below..

// {
//   "pkcs7": {
//     "verify": {
//       "certs": [
//         {
//           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
//           "serial": "0702A21A85B84B659E180A6EE6F5A365"
//         },
//         {
//           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
//           "serial": "008B5B75568454850B00CFAF3848CEB1A4"
//         },
//         {
//           "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
//           "serial": "619C55C32FF6BD1A7B7E0330D21C8F3C"
//         }
//       ],
//       "digestAlgorithms": [
//         "sha1"
//       ],
//       "signerInfo": [
//         {
//           "cert": {
//             "serialNumber": "619C55C32FF6BD1A7B7E0330D21C8F3C",
//             "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
//             "digestAlgOid": "1.3.14.3.2.26",
//             "digestAlgName": "SHA1"
//           },
//           "contentType": "1.2.840.113549.1.7.1",
//           "signingTime": "160428055000Z",
//           "messageDigest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY=",
//           "signingAlgOid": "1.2.840.113549.1.1.1",
//           "signingAlgName": "RSA-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": "160428055000Z"
//             },
//             "1.2.840.113549.1.9.4": {
//               "name": "messageDigest",
//               "digest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY="
//             },
//             "1.2.840.113549.1.9.15": {
//               "der": "MFAwCwYJYIZIAWUDBAECMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKA=="
//             },
//             "1.3.6.1.4.1.311.16.4": {
//               "der": "MIG7MIG...7fgMw0hyPPA=="
//             }
//           }
//         }
//       ]
//     }
//   }
// }

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

Chilkat.DtObj signingTime = new Chilkat.DtObj();
Chilkat.DtObj authAttrSigningTimeUtctime = new Chilkat.DtObj();
string issuerCN;
string serial;
string strVal;
string certSerialNumber;
string certIssuerCN;
string certDigestAlgOid;
string certDigestAlgName;
string contentType;
string messageDigest;
string signingAlgOid;
string signingAlgName;
string authAttrContentTypeName;
string authAttrContentTypeOid;
string authAttrSigningTimeName;
string authAttrMessageDigestName;
string authAttrMessageDigestDigest;
string authAttr1_2_840_113549_1_9_15Der;
string authAttr1_3_6_1_4_1_311_16_4Der;

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;
    certSerialNumber = json.StringOf("pkcs7.verify.signerInfo[i].cert.serialNumber");
    certIssuerCN = json.StringOf("pkcs7.verify.signerInfo[i].cert.issuerCN");
    certDigestAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid");
    certDigestAlgName = json.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName");
    contentType = json.StringOf("pkcs7.verify.signerInfo[i].contentType");
    json.DtOf("pkcs7.verify.signerInfo[i].signingTime",false,signingTime);
    messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].messageDigest");
    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");
    authAttr1_2_840_113549_1_9_15Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.2.840.113549.1.9.15\".der");
    authAttr1_3_6_1_4_1_311_16_4Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.\"1.3.6.1.4.1.311.16.4\".der");
    i = i + 1;
}