.NET Core C#

Verify a .p7m and get Algorithm Information

See more Digital Signatures Examples

Demonstrates how to verify a .p7m and then examine the algorithms used by the signature. .NET Core C#

bool success = false;

// 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 inFile = "qa_data/p7m/brainpoolP256r1.p7m";
string outFile = "qa_output/something.dat";

// Verify and extract the signed data.
success = crypt.VerifyP7M(inFile,outFile);
if (success == false) {
    Debug.WriteLine(crypt.LastErrorText);
    return;
}

// Examine details about the signature(s)
Chilkat.JsonObject json = new Chilkat.JsonObject();
crypt.GetLastJsonData(json);
json.EmitCompact = false;
Debug.WriteLine(json.Emit());

// Sample output

// {
//   "pkcs7": {
//     "verify": {
//       "digestAlgorithms": [
//         "sha256"
//       ],
//       "signerInfo": [
//         {
//           "cert": {
//             "serialNumber": "FFFFE552B302FFFFFF1E34C3ACEB2FFFF",
//             "issuerCN": "The common name of the cert...",
//             "issuerDN": "",
//             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
//             "digestAlgName": "SHA256"
//           },
//           "contentType": "1.2.840.113549.1.7.1",
//           "signingTime": "190409140500Z",
//           "messageDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
//           "signingAlgOid": "1.2.840.10045.4.3.2",
//           "signerDigest": "lQe9If7vZKFf/NlSYu5Esmlw3phVK/RFsbbb1uH73t8=",
//           "authAttr": [
//             {
//               "oid": "1.2.840.113549.1.9.3",
//               "oidName": "contentType"
//             },
//             {
//               "oid": "1.2.840.113549.1.9.5",
//               "oidName": "signingTime"
//             },
//             {
//               "oid": "1.2.840.113549.1.9.52",
//               "oidName": "1.2.840.113549.1.9.52",
//               "der": "MBs ... AwI="
//             },
//             {
//               "oid": "1.2.840.113549.1.9.4",
//               "oidName": "messageDigest"
//             },
//             {
//               "oid": "1.2.840.113549.1.9.16.2.47",
//               "oidName": "signingCertificateV2",
//               "der": "MCYw .. 7PlQ=="
//             },
//             {
//               "oid": "1.2.840.113549.1.9.20",
//               "oidName": "1.2.840.113549.1.9.20"
//             }
//           ]
//         }
//       ]
//     }
//   }
// }

// Code for parsing the above JSON...
int i;
int count_i;
string strVal;
string certSerialNumber;
string certIssuerCN;
string certIssuerDN;
string certDigestAlgOid;
string certDigestAlgName;
string contentType;
string signingTime;
string messageDigest;
string signingAlgOid;
string signerDigest;
int j;
int count_j;
string oid;
string oidName;
string der;

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");
    certIssuerDN = json.StringOf("pkcs7.verify.signerInfo[i].cert.issuerDN");
    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");
    signingTime = json.StringOf("pkcs7.verify.signerInfo[i].signingTime");
    messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].messageDigest");
    signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid");
    signerDigest = json.StringOf("pkcs7.verify.signerInfo[i].signerDigest");
    j = 0;
    count_j = json.SizeOfArray("pkcs7.verify.signerInfo[i].authAttr");
    while (j < count_j) {
        json.J = j;
        oid = json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].oid");
        oidName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].oidName");
        der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr[j].der");
        j = j + 1;
    }

    i = i + 1;
}

Debug.WriteLine("Success!");