(Objective-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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#import <CkoCrypt2.h>
#import <NSString.h>
#import <CkoJsonObject.h>
#import <CkoDtObj.h>

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

CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];

NSString *outputFile = @"qa_output/original.xml";
NSString *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 destPath: outputFile];
if (success == NO) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

NSLog(@"%@",@"Signature validated.");

// Now let's examine the information about the signature.
CkoJsonObject *json = [crypt LastJsonData];
if (crypt.LastMethodSuccess == NO) {
    // This should never be the case...
    NSLog(@"%@",@"No information available.");
    return;
}

json.EmitCompact = NO;
NSLog(@"%@",[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

CkoDtObj *authAttrSigningTimeUtctime = [[CkoDtObj alloc] init];
NSString *issuerCN = 0;
NSString *serial = 0;
NSString *strVal = 0;
NSString *certSubjectKeyIdentifier = 0;
NSString *certDigestAlgOid = 0;
NSString *certDigestAlgName = 0;
NSString *signingAlgOid = 0;
NSString *signingAlgName = 0;
NSString *authAttrContentTypeName = 0;
NSString *authAttrContentTypeOid = 0;
NSString *authAttrSigningTimeName = 0;
NSString *authAttrMessageDigestName = 0;
NSString *authAttrMessageDigestDigest = 0;
NSString *authAttrSigningCertificateV2Name = 0;
NSString *authAttrSigningCertificateV2Der = 0;

int i = 0;
int count_i = [[json SizeOfArray: @"pkcs7.verify.certs"] intValue];
while (i < count_i) {
    json.I = [NSNumber numberWithInt: 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"] intValue];
while (i < count_i) {
    json.I = [NSNumber numberWithInt: i];
    strVal = [json StringOf: @"pkcs7.verify.digestAlgorithms[i]"];
    i = i + 1;
}

i = 0;
count_i = [[json SizeOfArray: @"pkcs7.verify.signerInfo"] intValue];
while (i < count_i) {
    json.I = [NSNumber numberWithInt: 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" bLocal: NO dt: 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;
}