(Objective-C) P7S - Access Signature Information (date/time, certificate used, etc.)

Examine a PKCS7 signature (.p7s) and get information about it. Note: This example requires Chilkat v9.5.0.75 or greater.

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#import <CkoBinData.h>
#import <CkoCrypt2.h>
#import <CkoJsonObject.h>
#import <NSString.h>
#import <CkoDateTime.h>

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

// First load the .p7s file into a BinData object..
CkoBinData *bd = [[CkoBinData alloc] init];
BOOL success = [bd LoadFile: @"qa_data/p7s/sample.p7s"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load .p7s file.");
    return;
}

// IMPORTANT:  This example requires Chilkat v9.5.0.75 or greater.
CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];

// Assuming this is a signature that contains the original data that was signed..
success = [crypt OpaqueVerifyBd: bd];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

// Examine the LastJsonData after signature verification..
CkoJsonObject *json = [crypt LastJsonData];
json.EmitCompact = NO;
NSLog(@"%@",[json Emit]);

// --
// IMPORTANT:  This example requires Chilkat v9.5.0.75 or greater.
// --

// Sample output...
// Go to http://tools.chilkat.io/jsonParse.cshtml
// and paste the JSON into the online form to generate JSON parsing code.

// {
//   "pkcs7": {
//     "verify": {
//       "digestAlgorithms": [
//         "sha256"
//       ],
//       "signerInfo": [
//         {
//           "cert": {
//             "serialNumber": "AAC5FC48C0FD8FBB",
//             "issuerCN": "AC ABCDEF RFB v5",
//             "issuerDN": "",
//             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
//             "digestAlgName": "SHA-256"
//           },
//           "contentType": "1.2.840.113549.1.7.1",
//           "signingTime": "180607195054Z",
//           "messageDigest": "trzyxXbZ96z2M4mncyZ7BNMV4yIT92+5sS27Fu64iG8=",
//           "signingAlgOid": "1.2.840.113549.1.1.11",
//           "signerDigest": "trzyxXbZ96z2M4mncyZ7BNMV4yIT92+5sS27Fu64iG8="
//         },
//         {
//           "cert": {
//             "serialNumber": "324FB38ABD59723F",
//             "issuerCN": "AC ABCDEF RFB v5",
//             "issuerDN": "",
//             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
//             "digestAlgName": "SHA-256"
//           },
//           "contentType": "1.2.840.113549.1.7.1",
//           "signingTime": "180608182517Z",
//           "messageDigest": "trzyxXbZ96z2M4mncyZ7BNMV4yIT92+5sS27Fu64iG8=",
//           "signingAlgOid": "1.2.840.113549.1.1.11",
//           "signerDigest": "trzyxXbZ96z2M4mncyZ7BNMV4yIT92+5sS27Fu64iG8="
//         }
//       ]
//     }
//   }
// }
// 

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;
CkoDateTime *dt = [[CkoDateTime alloc] init];

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"];

    // The signingTime isin UTCTime format.
    // UTCTime values take the form of either "YYMMDDhhmm[ss]Z" or "YYMMDDhhmm[ss](+|-)hhmm"
    // Starting in Chilkat v9.5.0.77, the SetFromTimestamp method auto-recognizes the UTCTime format and parses it correctly.
    success = [dt SetFromTimestamp: signingTime];
    // To get the signingTime in other date/time formats, look at the online reference documentation for CkDateTime.
    // There are numerous methods such as GetAsDateTime, GetAsIso8601, GetAsUnixTime, GetAsRfc822, etc.

    messageDigest = [json StringOf: @"pkcs7.verify.signerInfo[i].messageDigest"];
    signingAlgOid = [json StringOf: @"pkcs7.verify.signerInfo[i].signingAlgOid"];
    signerDigest = [json StringOf: @"pkcs7.verify.signerInfo[i].signerDigest"];
    i = i + 1;
}

// println crypt.LastErrorText;
NSLog(@"%@",@"Success.");