(Objective-C) Load .crl, Convert to XML, Get Revoked Serial Numbers and Dates

Load a binary .crl file (Certificate Revocation List), converts to XML, and then gets the revoked certificate serial numbers and revocation dates.

Note: This example requires Chilkat v9.5.0.77 or greater.

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#import <CkoBinData.h>
#import <CkoAsn.h>
#import <CkoXml.h>
#import <NSString.h>
#import <CkoDateTime.h>

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

// Load a binary .crl file.
CkoBinData *bdCrl = [[CkoBinData alloc] init];
BOOL success = [bdCrl LoadFile: @"qa_data/crl/ca1.crl"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load CRL file.");
    return;
}

CkoAsn *asn = [[CkoAsn alloc] init];
success = [asn LoadBd: bdCrl];
if (success != YES) {
    NSLog(@"%@",asn.LastErrorText);
    return;
}

// Convert ASN.1 to XML and load into xml and re-emit for pretty printing..
CkoXml *xml = [[CkoXml alloc] init];
[xml LoadXml: [asn AsnToXml]];
success = [xml SaveXml: @"qa_output/crl.xml"];

// Use this online tool to generate parsing code from CRL XML: 
// Generate Parsing Code from XML

// Here's code to parse the XML.  This code was generated by the above tool,
// and then we modified it by removing unneeded code and changing some names
int i;
int count_i;
NSString *tagPath = 0;
int j;
int count_j;
int k;
int count_k;

NSString *revokedCertSerialHex = 0;
NSString *dateRevoked = 0;

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

i = 0;
count_i = [[xml NumChildrenHavingTag: @"sequence"] intValue];
while (i < count_i) {
    xml.I = [NSNumber numberWithInt: i];

    j = 0;
    count_j = [[xml NumChildrenHavingTag: @"sequence[i]|sequence"] intValue];
    while (j < count_j) {
        xml.J = [NSNumber numberWithInt: j];

        k = 0;
        count_k = [[xml NumChildrenHavingTag: @"sequence[i]|sequence[j]|sequence"] intValue];
        while (k < count_k) {
            xml.K = [NSNumber numberWithInt: k];

            // Get the revoked certificate's serial number in uppercase hex.
            revokedCertSerialHex = [xml GetChildContent: @"sequence[i]|sequence[j]|sequence[k]|int"];
            NSLog(@"%@%@",@"serial number: ",revokedCertSerialHex);

            // Get the date/time revoked.  It will be a string formatted as "YYMMDDhhmmssZ", such as "181023093028Z"
            dateRevoked = [xml GetChildContent: @"sequence[i]|sequence[j]|sequence[k]|utctime"];

            // Starting in Chilkat v9.5.0.77, date/time strings formatted as YYMMDDhhmmssZ can be parsed as follows:
            [dt SetFromTimestamp: dateRevoked];
            NSLog(@"%@%@",@"date revoked: ",[dt GetAsRfc822: NO]);

            k = k + 1;
        }

        j = j + 1;
    }

    i = i + 1;
}