(PureBasic) Create Egypt ITIDA CAdES-BES Signature with Automatic JSON Canonicalization

See more Egypt ITIDA Examples

Demonstrates how to create a .p7s signature that fits Egypt's ITIDA requirements where Chilkat automatically does the ITIDA JSON canonicalization.

Note: This example requires Chilkat v9.5.0.75 or greater.

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IncludeFile "CkCert.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

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

    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkVerboseLogging(crypt, 1)

    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCert::setCkVerboseLogging(cert, 1)

    ; Set the smart card PIN, which will be needed for signing.
    CkCert::setCkSmartCardPin(cert, "12345678")

    ; There are many ways to load the certificate.  
    ; This example was created for a customer using an ePass2003 USB token.
    ; Assuming the USB token is the only source of a hardware-based private key..
    success.i = CkCert::ckLoadFromSmartcard(cert,"")
    If success <> 1
        Debug CkCert::ckLastErrorText(cert)
        CkCrypt2::ckDispose(crypt)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; Tell the crypt class to use this cert.
    success = CkCrypt2::ckSetSigningCert(crypt,cert)
    If success <> 1
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkCrypt2::ckDispose(crypt)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    cmsOptions.i = CkJsonObject::ckCreate()
    If cmsOptions.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Setting "DigestData" causes OID 1.2.840.113549.1.7.5 (digestData) to be used.
    CkJsonObject::ckUpdateBool(cmsOptions,"DigestData",1)
    CkJsonObject::ckUpdateBool(cmsOptions,"OmitAlgorithmIdNull",1)

    ; Indicate that we are passing normal JSON and we want Chilkat do automatically
    ; do the ITIDA JSON canonicalization:
    CkJsonObject::ckUpdateBool(cmsOptions,"CanonicalizeITIDA",1)

    CkCrypt2::setCkCmsOptions(crypt, CkJsonObject::ckEmit(cmsOptions))

    ; The CadesEnabled property applies to all methods that create CMS/PKCS7 signatures. 
    ; To create a CAdES-BES signature, set this property equal to true. 
    CkCrypt2::setCkCadesEnabled(crypt, 1)

    CkCrypt2::setCkHashAlgorithm(crypt, "sha256")

    jsonSigningAttrs.i = CkJsonObject::ckCreate()
    If jsonSigningAttrs.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckUpdateInt(jsonSigningAttrs,"contentType",1)
    CkJsonObject::ckUpdateInt(jsonSigningAttrs,"signingTime",1)
    CkJsonObject::ckUpdateInt(jsonSigningAttrs,"messageDigest",1)
    CkJsonObject::ckUpdateInt(jsonSigningAttrs,"signingCertificateV2",1)
    CkCrypt2::setCkSigningAttributes(crypt, CkJsonObject::ckEmit(jsonSigningAttrs))

    ; By default, all the certs in the chain of authentication are included in the signature.
    ; If desired, we can choose to only include the signing certificate:
    CkCrypt2::setCkIncludeCertChain(crypt, 0)

    ; Pass a JSON document such as the following.  Chilkat will do the ITIDA canonicalization.
    ; (It is the canonicalized JSON that gets signed.)

    ;       {
    ;          "issuer":{
    ;             "address":{
    ;                "branchID":"0",
    ;                "country":"EG",
    ;                "regionCity":"Cairo",
    ;                "postalCode":"",
    ;                "buildingNumber":"0",
    ;                "street":"123rd Street",
    ;                "governate":"GOVERNATE"
    ;             },
    ;             "type":"B",
    ;             "id":"209999899",
    ;             "name":"Xyz SAE"
    ;          },
    ;          "receiver":{
    ;             "address":{
    ;                "country":"EG",
    ;                "regionCity":"CAIRO",
    ;                "postalCode":"11435",
    ;                "buildingNumber":"0",
    ;                "street":"Autostrad Road Abc",
    ;                "governate":"GOVERNATE"
    ;             },
    ;             "type":"B",
    ;             "id":"999999999",
    ;             "name":"XYZ EGYPT FOR TRADE"
    ;          },
    ;          "documentType":"I",
    ;          "documentTypeVersion":"1.0",
    ;          "dateTimeIssued":"2020-11-15T11:04:53Z",
    ;          "taxpayerActivityCode":"1073",
    ;          "internalID":"ZZZZ999",
    ;          "purchaseOrderReference":"2009199918",
    ;          "salesOrderReference":"",
    ;          "payment":{
    ;             "bankName":"",
    ;             "bankAddress":"",
    ;             "bankAccountNo":"",
    ;             "bankAccountIBAN":"",
    ;             "swiftCode":"",
    ;             "terms":""
    ;          },
    ;          "delivery":{
    ;             "approach":"",
    ;             "packaging":"",
    ;             "dateValidity":"",
    ;             "exportPort":"",
    ;             "countryOfOrigin":"EG",
    ;             "grossWeight":0,
    ;             "netWeight":0,
    ;             "terms":""
    ;          },
    ;          "invoiceLines":[
    ;             {
    ;                "description":"CDM Widget 48GX99X12BA",
    ;                "itemType":"GS1",
    ;                "itemCode":"7622213335056",
    ;                "unitType":"CS",
    ;                "quantity":1.00,
    ;                "unitValue":{
    ;                   "currencySold":"EGP",
    ;                   "amountEGP":588.67,
    ;                   "amountSold":0,
    ;                   "currencyExchangeRate":0
    ;                },
    ;                "salesTotal":588.67,
    ;                "total":603.97,
    ;                "valueDifference":0,
    ;                "totalTaxableFees":0,
    ;                "netTotal":529.8,
    ;                "itemsDiscount":0,
    ;                "discount":{
    ;                   "rate":10.00,
    ;                   "amount":58.87
    ;                },
    ;                "taxableItems":[
    ;                   {
    ;                      "taxType":"T1",
    ;                      "amount":74.17,
    ;                      "subType":"No sub",
    ;                      "rate":14.00
    ;                   }
    ;                ],
    ;                "internalCode":"9099994"
    ;             }
    ;          ],
    ;          "totalSales":588.67,
    ;          "totalSalesAmount":588.67,
    ;          "totalDiscountAmount":58.87,
    ;          "netAmount":529.80,
    ;          "taxTotals":[
    ;             {
    ;                "taxType":"T1",
    ;                "amount":74.17
    ;             }
    ;          ],
    ;          "extraDiscountAmount":0,
    ;          "totalItemsDiscountAmount":0,
    ;          "totalAmount":603.97,
    ;       }
    ; 

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkJsonObject::ckLoadFile(json,"qa_data/itida/sdk.invoicing.eta.gov.eg/files/one-doc.json")
    If success = 0
        Debug CkJsonObject::ckLastErrorText(json)
        CkCrypt2::ckDispose(crypt)
        CkCert::ckDispose(cert)
        CkJsonObject::ckDispose(cmsOptions)
        CkJsonObject::ckDispose(jsonSigningAttrs)
        CkJsonObject::ckDispose(json)
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(json, 0)

    ; Create the CAdES-BES signature.
    CkCrypt2::setCkEncodingMode(crypt, "base64")

    ; Make sure we sign the utf-8 byte representation of the JSON string
    CkCrypt2::setCkCharset(crypt, "utf-8")

    sigBase64.s = CkCrypt2::ckSignStringENC(crypt,CkJsonObject::ckEmit(json))
    If CkCrypt2::ckLastMethodSuccess(crypt) = 0
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkCrypt2::ckDispose(crypt)
        CkCert::ckDispose(cert)
        CkJsonObject::ckDispose(cmsOptions)
        CkJsonObject::ckDispose(jsonSigningAttrs)
        CkJsonObject::ckDispose(json)
        ProcedureReturn
    EndIf

    Debug "Base64 signature:"
    Debug sigBase64

    ; Add the signature to the JSON.
    CkJsonObject::ckUpdateString(json,"signatures[0].signatureType","I")
    CkJsonObject::ckUpdateString(json,"signatures[0].value",sigBase64)

    Debug "JSON with signature added:"
    Debug CkJsonObject::ckEmit(json)


    CkCrypt2::ckDispose(crypt)
    CkCert::ckDispose(cert)
    CkJsonObject::ckDispose(cmsOptions)
    CkJsonObject::ckDispose(jsonSigningAttrs)
    CkJsonObject::ckDispose(json)


    ProcedureReturn
EndProcedure