Objective-C

Calculate HRMC IRMark

See more XML Digital Signatures Examples

Demonstrates how to calculate an IRmark for an HMRC GovTalkMessage XML document.

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Objective-C

#import <CkoXml.h>
#import <CkoXmlDSig.h>
#import <NSString.h>
#import <CkoCrypt2.h>

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

//  First build a sample (but incomplete) GovTalkMessage.
//  You can replace this code with a call to LoadXml or LoadXmlFile..
//  
//  Note: The online tool at https://tools.chilkat.io/xmlCreate.cshtml
//  can be used to generate XML code that creates a given XML document.
CkoXml *xml = [[CkoXml alloc] init];
xml.Tag = @"GovTalkMessage";
[xml AddAttribute: @"xmlns" value: @"http://www.govtalk.gov.uk/CM/envelope"];
[xml UpdateAttrAt: @"Body|Message" autoCreate: YES attrName: @"xmlns" attrValue: @"urn:g3.ge:dea:call:SendDocument:v1"];
[xml UpdateChildContent: @"Body|Message" value: @"................"];

//  This is the XML created:
//  <?xml version="1.0" encoding="utf-8" ?>
//  <GovTalkMessage xmlns="http://www.govtalk.gov.uk/CM/envelope">
//      <Body>
//          <Message xmlns="urn:g3.ge:dea:call:SendDocument:v1">................</Message>
//      </Body>
//  </GovTalkMessage>

NSLog(@"%@",[xml GetXml]);

//  Canonicalize the XML (using C14N)
CkoXmlDSig *xdsig = [[CkoXmlDSig alloc] init];
BOOL withComments = NO;
NSString *canonXml = [xdsig CanonicalizeXml: [xml GetXml] version: @"C14N" withComments: withComments];

//  Return the base64 SHA-1 HASH of the canonical XML.
CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];
crypt.HashAlgorithm = @"sha1";
crypt.EncodingMode = @"base64";
NSString *irmark = [crypt HashStringENC: canonXml];

NSLog(@"%@%@",@"IRMark = ",irmark);