(Objective-C) Verify a .p7m and get Algorithm Information

Demonstrates how to verify a .p7m and then examine the algorithms used by the signature.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoCrypt2.h>
#import <NSString.h>
#import <CkoJsonObject.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 *inFile = @"qa_data/p7m/brainpoolP256r1.p7m";
NSString *outFile = @"qa_output/something.dat";

// Verify and extract the signed data.
BOOL success = [crypt VerifyP7M: inFile destPath: outFile];
if (success == NO) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

// Examine details about the signature(s)
CkoJsonObject *json = [crypt LastJsonData];
json.EmitCompact = NO;
NSLog(@"%@",[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;
NSString *strVal = 0;
NSString *certSerialNumber = 0;
NSString *certIssuerCN = 0;
NSString *certIssuerDN = 0;
NSString *certDigestAlgOid = 0;
NSString *certDigestAlgName = 0;
NSString *contentType = 0;
NSString *signingTime = 0;
NSString *messageDigest = 0;
NSString *signingAlgOid = 0;
NSString *signerDigest = 0;
int j;
int count_j;
NSString *oid = 0;
NSString *oidName = 0;
NSString *der = 0;

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];
    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"] intValue];
    while (j < count_j) {
        json.J = [NSNumber numberWithInt: 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;
}

NSLog(@"%@",@"Success!");