(Objective-C) Examine KeyInfo Certificate in XML Signature

This example loads signed XML and gets the signing certificate, assuming the certificate is contained in X509Certificate within the KeyInfo.

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

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

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

CkoXmlDSig *dsig = [[CkoXmlDSig alloc] init];
CkoStringBuilder *sbXml = [[CkoStringBuilder alloc] init];

BOOL success = [sbXml LoadFile: @"c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml" charset: @"utf-8"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load XML file.");
    return;
}

success = [dsig LoadSignatureSb: sbXml];
if (success != YES) {
    NSLog(@"%@",dsig.LastErrorText);
    return;
}

// Get the KeyInfo XML.
CkoXml *xmlKeyInfo = [dsig GetKeyInfo];
if (dsig.LastMethodSuccess != YES) {
    NSLog(@"%@",dsig.LastErrorText);
    return;
}

NSLog(@"%@",[xmlKeyInfo GetXml]);
NSLog(@"%@",@"----");

// Assuming the X509Certificate is in the KeyInfo, it will look like this:

//   <ds:KeyInfo Id="...">
//     <ds:KeyValue>
//     ...  
//     <ds:X509Data>
//       <ds:X509Certificate>MIIHAz...</ds:X509Certificate>
//     </ds:X509Data>
//   </ds:KeyInfo>
NSString *certBase64 = [xmlKeyInfo GetChildContent: @"*:X509Data|*:X509Certificate"];
if (xmlKeyInfo.LastMethodSuccess != YES) {
    NSLog(@"%@",@"No X509Certificate found in the KeyInfo.");
    return;
}

// Load a certificate object w/ the base64.
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadFromBase64: certBase64];
if (success != YES) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

// Examine the cert..
NSLog(@"%@%@",@"SubjectDN: ",cert.SubjectDN);
NSLog(@"%@%@",@"IssuerDN: ",cert.IssuerDN);
NSLog(@"%@%@",@"SerialNumber as Decimal: ",cert.SerialDecimal);