(Objective-C) Create XML Signature with KeyInfo / X509Data / X509Certificate

This example demonstrates how to create an XML Digital Signature where the KeyInfo element contains an X509Data element, which in turn contains an X509Certificate element which contains the base64-encoded certificate.

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#import <CkoStringBuilder.h>
#import <CkoHttp.h>
#import <CkoBinData.h>
#import <CkoPfx.h>
#import <NSString.h>
#import <CkoCert.h>
#import <CkoXmlDSigGen.h>

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

// To begin, we'll need a PFX containing a certificate and private key, and the SOAP XML to be signed.
// Chilkat provides sample data at chilkatsoft.com and chilkatdownload.com, and our first step is to download.

// -------------------------------------------------------------------------
// Step 1: Get the SOAP XML to be signed.
// 
CkoStringBuilder *sbXml = [[CkoStringBuilder alloc] init];

CkoHttp *http = [[CkoHttp alloc] init];
BOOL success = [http QuickGetSb: @"https://www.chilkatsoft.com/exampleData/soapToSign.xml" sbContent: sbXml];
if (success != YES) {
    NSLog(@"%@",http.LastErrorText);
    return;
}

// The SOAP XML contains this:

// <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
// <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
//     <SOAP-ENV:Header>
//         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"></wsse:Security>
//     </SOAP-ENV:Header>
//     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
//         <z:FooBar xmlns:z="http://example.com" />
//     </SOAP-ENV:Body>
// </SOAP-ENV:Envelope>

// -------------------------------------------------------------------------
// Step 2: Get the test certificate and private key stored in a .pfx
// 
CkoBinData *pfxData = [[CkoBinData alloc] init];
success = [http QuickGetBd: @"https://chilkatdownload.com/example_data/testcertificate.pfx" binData: pfxData];
if (success != YES) {
    NSLog(@"%@",http.LastErrorText);
    return;
}

CkoPfx *pfx = [[CkoPfx alloc] init];
NSString *password = @"test";
success = [pfx LoadPfxEncoded: [pfxData GetEncoded: @"base64"] encoding: @"base64" password: password];
if (success != YES) {
    NSLog(@"%@",pfx.LastErrorText);
    return;
}

// -------------------------------------------------------------------------
// Step 3: Get the certificate from the PFX.
// 
CkoCert *cert = [pfx GetCert: [NSNumber numberWithInt: 0]];
if (pfx.LastMethodSuccess != YES) {
    NSLog(@"%@",pfx.LastErrorText);
    return;
}

// Prepare for signing...
CkoXmlDSigGen *gen = [[CkoXmlDSigGen alloc] init];

// Indicate where the Signature will be inserted.
gen.SigLocation = @"SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security";

// Add a reference to the fragment of the XML to be signed.

// Note: "Body" refers to the XML element having an "id" equal to "Body", where "id" is case insensitive
// and where any namespace might qualify the attribute.  In this case, the SOAP-ENV:Body fragment is signed
// NOT because the tag = "Body", but because it has SOAP-SEC:id="Body"
[gen AddSameDocRef: @"Body" digestMethod: @"sha1" canonMethod: @"EXCL_C14N" prefixList: @"" refType: @""];

// (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
gen.SignedInfoPrefixList = @"wsse SOAP-ENV";

// Provide the private key for signing via the certificate, and indicate that
// we want the base64 of the certificate embedded in the KeyInfo.
gen.KeyInfoType = @"X509Data";
gen.X509Type = @"Certificate";

// Note: Because our certificate was loaded from a PFX which also contained the private key,
// Chilkat automatically knows and has the private key associated with the certificate.
// We set bUsePrivateKey to tell the SetX509Cert method to automatically use the private key
// associated with the certificate for signing.  If, for example, we obtained the certificate
// by loading from a .cer file, then we would not already have the associated private key.
// In that case, the application could explicitly load the cert's private key from some
// other source, such as a .key, .pem, etc. and then call gen.SetPrivateKey.
BOOL bUsePrivateKey = YES;
success = [gen SetX509Cert: cert usePrivateKey: bUsePrivateKey];
if (success != YES) {
    NSLog(@"%@",gen.LastErrorText);

    return;
}

// Everything's specified.  Now create and insert the Signature
success = [gen CreateXmlDSigSb: sbXml];
if (success != YES) {
    NSLog(@"%@",gen.LastErrorText);
    return;
}

// Examine the XML with the digital signature inserted
NSLog(@"%@",[sbXml GetAsString]);

// Here is the actual output.  A pretty-printed version of the output is shown below, but the addition of whitespace
// in the XML invalidates the signature.

// Actual output:
// <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
// <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
//     <SOAP-ENV:Header>
//         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"><ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"><InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV"/></ds:CanonicalizationMethod><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/><ds:Reference URI="#Body"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/><ds:DigestValue>PIiVPpuMc1jGpWaL8ftzTOcc4gc=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>dlSGYRtxv8DiGQ9THPEdPTlbwjkidCUEutVWkqhnjzKOxjl6EZPp6ibf7ogrn1QJAabo7eb/d2UjD8LXzQYB+q9OmN29dsDcg4i9hzpttjU9xt8Sc3IgdaQ+6NXStWd1AKrjNTCY52sOpIWh45uff/yjf9ynsbCo/UR8+hk6ZDCrM78YEyMj52miXzVQtSZ7f+bvWtz8iPppXXC+/zwGPAI9EPC+9uRHRRh4vzGwid+clMmh9FF/0Oe4n0G5dBZvwLPncwOMg0UxLVs63ZRdTCSku4oKReQieqNr7+hzBAKaS8NRpxMtx2XC5aR0wYMkYT9API/vYubeU0L3r4lplw==</ds:SignatureValue><ds:KeyInfo><ds:X509Data><ds:X509Certificate>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</ds:X509Certificate></ds:X509Data></ds:KeyInfo></ds:Signature></wsse:Security>
//     </SOAP-ENV:Header>
//     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
//         <z:FooBar xmlns:z="http://example.com" />
//     </SOAP-ENV:Body>
// </SOAP-ENV:Envelope>

// ----------------------------------------------------------------
// Pretty-printed output (invalidates the signature)
// This makes it easier to see the base64 certificate contained within the KeyInfo.

// <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
// <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
//     <SOAP-ENV:Header>
//         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1">
//             <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
//                 <ds:SignedInfo>
//                     <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">
//                         <InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV" />
//                     </ds:CanonicalizationMethod>
//                     <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />
//                     <ds:Reference URI="#Body">
//                         <ds:Transforms>
//                             <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
//                         </ds:Transforms>
//                         <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
//                         <ds:DigestValue>PIiVPpuMc1jGpWaL8ftzTOcc4gc=</ds:DigestValue>
//                     </ds:Reference>
//                 </ds:SignedInfo>
//                 <ds:SignatureValue>dlSGYRtxv8DiGQ9THPEdPTlbwjkidCUEutVWkqhnjzKOxjl6EZPp6ibf7ogrn1QJAabo7eb/d2UjD8LXzQYB+q9OmN29dsDcg4i9hzpttjU9xt8Sc3IgdaQ+6NXStWd1AKrjNTCY52sOpIWh45uff/yjf9ynsbCo/UR8+hk6ZDCrM78YEyMj52miXzVQtSZ7f+bvWtz8iPppXXC+/zwGPAI9EPC+9uRHRRh4vzGwid+clMmh9FF/0Oe4n0G5dBZvwLPncwOMg0UxLVs63ZRdTCSku4oKReQieqNr7+hzBAKaS8NRpxMtx2XC5aR0wYMkYT9API/vYubeU0L3r4lplw==</ds:SignatureValue>
//                 <ds:KeyInfo>
//                     <ds:X509Data>
//                         <ds:X509Certificate>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</ds:X509Certificate>
//                     </ds:X509Data>
//                 </ds:KeyInfo>
//             </ds:Signature>
//         </wsse:Security>
//     </SOAP-ENV:Header>
//     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
//         <z:FooBar xmlns:z="http://example.com" />
//     </SOAP-ENV:Body>
// </SOAP-ENV:Envelope>