Objective-C

Get Certificate Authority Information Access

See more Certificates Examples

Demonstrates how to get a certificate's Authority Information Access extension data (if it exists).

Note: This example requires Chilkat v9.5.0.76 or greater.

Objective-C

#import <CkoCert.h>
#import <NSString.h>
#import <CkoXml.h>
#import <CkoStringBuilder.h>

BOOL success = NO;

CkoCert *cert = [[CkoCert alloc] init];

success = [cert LoadFromFile: @"qa_data/certs/test_haswdt.cer"];
if (success != YES) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

//  Get the Authority Information Access extension, which is at OID 1.3.6.1.5.5.7.1.1
NSString *extensionXmlStr = [cert GetExtensionAsXml: @"1.3.6.1.5.5.7.1.1"];
if (cert.LastMethodSuccess == NO) {
    NSLog(@"%@",@"Certificate does not have the AuthInfoAccess extension.");
    return;
}

CkoXml *xml = [[CkoXml alloc] init];
[xml LoadXml: extensionXmlStr];

//  See what we have..
NSLog(@"%@",[xml GetXml]);

//  We should get XML like this:

//  <?xml version="1.0" encoding="utf-8" ?>
//  <sequence>
//      <sequence>
//          <oid>1.3.6.1.5.5.7.48.2</oid>
//          <contextSpecific tag="6" constructed="0">aHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1
//  cmVFbWFpbENBLmNydA==</contextSpecific>
//      </sequence>
//      <sequence>
//          <oid>1.3.6.1.5.5.7.48.1</oid>
//          <contextSpecific tag="6" constructed="0">aHR0cDovL29jc3AuY29tb2RvY2EuY29t</contextSpecific>
//      </sequence>
//  </sequence>

//  Typically, a certificate AIA(Authority Information access) contains 2 parts:
//  
//      On-line Certificate Status Protocol (1.3.6.1.5.5.7.48.1)
//      Certification Authority Issuer (1.3.6.1.5.5.7.48.2)
//  
//  The base64 content for each OID (in this case) is just a string.  
//  The data can be accessed and decoded like this:

CkoStringBuilder *sbOcsp = [[CkoStringBuilder alloc] init];
success = [xml GetChildContentSb: @"/C/oid,1.3.6.1.5.5.7.48.1|++" sb: sbOcsp];
if (success == YES) {
    [sbOcsp Decode: @"base64" charset: @"utf-8"];
    NSLog(@"%@%@",@"1.3.6.1.5.5.7.48.1:  ",[sbOcsp GetAsString]);
}

CkoStringBuilder *sbIssuer = [[CkoStringBuilder alloc] init];
success = [xml GetChildContentSb: @"/C/oid,1.3.6.1.5.5.7.48.2|++" sb: sbIssuer];
if (success == YES) {
    [sbIssuer Decode: @"base64" charset: @"utf-8"];
    NSLog(@"%@%@",@"1.3.6.1.5.5.7.48.2:  ",[sbIssuer GetAsString]);
}

//  The output looks like this:

//  1.3.6.1.5.5.7.48.1:  http://ocsp.comodoca.com
//  1.3.6.1.5.5.7.48.2:  http://crt.comodoca.com/COMODORSAClientAuthenticationandSecureEmailCA.crt

//  -------------------------------------------------------------------------------
//  Note: The Chilkat path passed to GetChildContentSb is composed of two commands:
//  The first command is "/C/oid,1.3.6.1.5.5.7.48.1".   It says "traverse the XML tree from the caller
//  node and stop at the 1st node having tag = "oid" and content = "1.3.6.1.5.5.7.48.1".
//  The "|" char separates the 1st command from the 2nd.
//  The 2nd command is "++" and says "move to the next sibling".