Xbase++

Create XML Signature with External Data Reference

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature where the data is external. In this case, the data is a JPG file.

This example requires Chilkat v9.5.0.69 or greater.

Xbase++

LOCAL nSuccess
LOCAL cUrl
LOCAL oHttp
LOCAL oSbXml
LOCAL oRsaKey
LOCAL oXmlSigGen
LOCAL cJpgUrl
LOCAL oJpgData

nSuccess := 0

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

//  This example inserts an XML signature in the following XML:

//  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
//  <abc>
//    <xyz>
//      <jpg>
//          <name>starfish.jpg</name>
//          <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
//      </jpg>
//    </xyz>
//  </abc>

//  The above XML is available at https://www.chilkatsoft.com/exampleData/addSignatureToThis.xml
//  First fetch the XML:

cUrl := "https://www.chilkatsoft.com/exampleData/addSignatureToThis.xml"
oHttp := CreateObject("Chilkat.Http")
oSbXml := CreateObject("Chilkat.StringBuilder")
nSuccess := oHttp:QuickGetSb(cUrl, oSbXml)
IF (nSuccess != 1)
    ? oHttp:LastErrorText
    oHttp:destroy()
    oSbXml:destroy()
    RETURN
ENDIF

//  We'll use an RSA private key for signing.  
oRsaKey := CreateObject("Chilkat.PrivateKey")
nSuccess := oRsaKey:LoadPemFile("qa_data/rsa/rsaPrivKey_pkcs8.pem")
IF (nSuccess != 1)
    ? oRsaKey:LastErrorText
    oHttp:destroy()
    oSbXml:destroy()
    oRsaKey:destroy()
    RETURN
ENDIF

oXmlSigGen := CreateObject("Chilkat.XmlDSigGen")

//  Indicate were the Signature will be inserted:
oXmlSigGen:SigLocation := "abc|xyz|jpg"

//  Provide the RSA key to be used for signing:
oXmlSigGen:SetPrivateKey(oRsaKey)

//  Fetch the JPG image data.
cJpgUrl := "https://www.chilkatsoft.com/images/starfish.jpg"
oJpgData := CreateObject("Chilkat.BinData")
nSuccess := oHttp:QuickGetBd(cJpgUrl, oJpgData)
IF (nSuccess != 1)
    ? oHttp:LastErrorText
    oHttp:destroy()
    oSbXml:destroy()
    oRsaKey:destroy()
    oXmlSigGen:destroy()
    oJpgData:destroy()
    RETURN
ENDIF

//  Add the external data reference:
oXmlSigGen:AddExternalBinaryRef(cJpgUrl, oJpgData, "sha256", "")

//  Create the XML digital signature:
nSuccess := oXmlSigGen:CreateXmlDSigSb(oSbXml)
IF (nSuccess != 1)
    ? oXmlSigGen:LastErrorText
    oHttp:destroy()
    oSbXml:destroy()
    oRsaKey:destroy()
    oXmlSigGen:destroy()
    oJpgData:destroy()
    RETURN
ENDIF

//  Examine the XML that now contains the Signature:
? oSbXml:GetAsString()

//  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
//  <abc>
//    <xyz>
//      <jpg>
//          <name>starfish.jpg</name>
//          <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
//      <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#"/><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/><ds:Reference URI="https://www.chilkatsoft.com/images/starfish.jpg"><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>AOU810yJV5Np/DnO29qpObqiTSTTCDvxGsX5ayiTYXI=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>ApHRr6nilNrzt3dLveC9zlPoSllaCMfHsbAwr+vYBPkHkJ4wD5LzDDhi1tSJZAAeTckmvSqIG3Wi0rgXQiSM644MD3coBFx4QgrY+GZ+XJJE2Y0Ye3VvaQBiRdUW3INGsW4GLubncgQk5JhuAQjo6O/GKpfEuYqUJj/6CLHLQwMPwbZ2043ykgzuPFoOZf6EydJMBAn1ORMvrpUn+zuA9UngOTGap6eWE4CeiNx23BRC2wSztbUjdCLcqXvgiYu/v0tBNaTcwy7b6+IFtwv/lNUUBUQJ/3p+aErzFn3wLeH3yeqpDCU0U6Dqu5SS1jYupcWWsLHJjYnj2066DPJi/g==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:RSAKeyValue><ds:Modulus>sXeRhM55P13FbpNcXAMR3olbw2Wa6keZIHu5YTZYUBTlYWId+pNiwUz3zFIEo+0IfYR0H27ybIycQO+1IIzJofUFNMAL3tZps2OKPlsjuCPls6kXpXhv/gvhux8LrCtp4PcKWqJ6QVOZKChc7WAx40qFWzHi57ueqRTv3x0kESqGg/VjsqyTEvb55psJO2RsfhLT7+YVh3hImRM3RDaJdkTkPuOxeFyT6N7VXD09329sLuS3QkUbE9zEKDnz9X3d8dEQdJhSI9ba5fxl8R7fu8pB67ElfzFml96X1jLFtzy1pzOT5Fc4ROcaqlYckVzdBq9sxezm6MYmDBjNAcibRw==</ds:Modulus><ds:Exponent>AQAB</ds:Exponent></ds:RSAKeyValue></ds:KeyValue></ds:KeyInfo></ds:Signature></jpg>
//    </xyz>
//  </abc>
//

oHttp:destroy()
oSbXml:destroy()
oRsaKey:destroy()
oXmlSigGen:destroy()
oJpgData:destroy()