Objective-C

SII Chile - FRMA Signature Computation and Add to XML

See more XML Digital Signatures Examples

Compute the FRMA signature of a <DA> element enclosed inside a <CAF> element of the XML to be signed. Objective-C

#import <CkoXml.h>
#import <CkoStringBuilder.h>
#import <CkoPrivateKey.h>
#import <CkoRsa.h>
#import <NSString.h>

BOOL success = NO;

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

//  Also see:  Compute the FRMT Signature and Add to XML

CkoXml *xml = [[CkoXml alloc] init];

//  Load the unsigned XML that contains the following:

//  <DTE version="1.0">
//    <Documento ID="F60T33">
//          <TED version="1.0">
//              <DD>
//  		...
//                  <CAF version="1.0">
//                      <DA>
//  			...
//                      </DA>
//  			... The FRMA will be added here ...
//                  </CAF>
//                  ...
//              </DD>
//              ... The FRMT will be added here in another example ...
//          </TED>
//    </Documento>
//  </DTE>

success = [xml LoadXmlFile: @"qa_data/xml_dsig/sii_cl/test_0.xml"];
if (success == NO) {
    NSLog(@"%@",@"Failed to load initial XML file.");
    return;
}

//  Get a reference to the "DA" element
CkoXml *daXml = [xml FindChild: @"Documento|TED|DD|CAF|DA"];
if (xml.LastMethodSuccess == NO) {
    NSLog(@"%@",@"Failed to find DA element");
    return;
}

//   We need to get the "flattened" DA XML where:
//     - No whitespace between elements.
//     - The 5 pre-defined entities are converted.
//     - The text is encoded in the ISO-8859-1 character set (Latin-1), 
CkoStringBuilder *sbFlattened = [[CkoStringBuilder alloc] init];
daXml.EmitCompact = YES;
daXml.EmitXmlDecl = NO;
[daXml GetXmlSb: sbFlattened];

//  Compute the SHA-1 message digest of the iso-8859-1 byte representation, 
//  and sign it with our RSA private key, getting the result in base64 format.

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
success = [privKey LoadAnyFormatFile: @"qa_data/rsa/rsaPrivKey_pkcs8.pem" password: @""];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

CkoRsa *rsa = [[CkoRsa alloc] init];
[rsa UsePrivateKey: privKey];

rsa.EncodingMode = @"base64";
rsa.Charset = @"iso-8859-1";
NSString *sig = [rsa SignStringENC: [sbFlattened GetAsString] hashAlg: @"sha1"];

//  Add the FRMA signature element to the XML.
[xml UpdateChildContent: @"Documento|TED|DD|CAF|FRMA" value: sig];
[xml UpdateAttrAt: @"Documento|TED|DD|CAF|FRMA" autoCreate: YES attrName: @"algoritmo" attrValue: @"SHA1withRSA"];

//  See what we have:
xml.EmitCompact = NO;
xml.EmitXmlDecl = YES;
NSLog(@"%@",[xml GetXml]);

[xml SaveXml: @"qa_data/xml_dsig/sii_cl/test_1.xml"];