CODEWITHSUNDEEP
phpxmlsignxml-signature
awavi
awavi

Reputation: 847

Sign xml with XADES-EPES using PHP

I need to sign a document using XADES-EPES and I am using PHP for that purpose.

Using the xml below, I have been able to calculate the digest value <ds:DigestValue>ql0urtXTsc9W0GMIhTdzYHXnQYfnieoIttOBn9fGw7A=</ds:DigestValue> in the example given below, but I wonder how the other <ds:DigestValue>5JVZPTwN5Lj0sGTfFzaUeMKCo/xbCAj7fw6TLUFtZIk=</ds:DigestValue> is calculated.

I am using this XML as a test case:

<?xml version="1.0" encoding="UTF-8" xs:xmlns="https://tribunet.hacienda.go.cr/docs/esquemas/2016/v4.2/FacturaElectronica_V.4.2.xsd"?>
<FacturaElectronica>
    <Clave>1</Clave>
    <NumeroConsecutivo>1</NumeroConsecutivo>
    <FechaEmision>1</FechaEmision>
    <Emisor>1</Emisor>
    <Receptor>1</Receptor>
    <CondicionVenta>1</CondicionVenta>
    <CondicionVenta>1</CondicionVenta>
    <MedioPago>1</MedioPago>
    <DetalleServicio>1</DetalleServicio>
    <ResumenFactura>1</ResumenFactura>
    <Normativa>1</Normativa>
</FacturaElectronica>

I am supposed to sign it with something similar to this (note: the SignatureValue and the X509Certificate have been truncated):

<ds:Signature Id="id-e34ffbff277e8d1432e864436aa11882" 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 Id="r-id-1" Type="" URI="">
            <ds:Transforms>
                <ds:Transform Algorithm="http://www.w3.org/TR/1999/REC-xpath-19991116">
                    <ds:XPath>not(ancestor-or-self::ds:Signature)</ds:XPath>
                </ds:Transform>
                <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
            </ds:Transforms>
            <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
            <ds:DigestValue>ql0urtXTsc9W0GMIhTdzYHXnQYfnieoIttOBn9fGw7A=</ds:DigestValue>
        </ds:Reference>
        <ds:Reference Type="http://uri.etsi.org/01903#SignedProperties" URI="#xades-ide34ffbff277e8d1432e864436aa11882">
            <ds:Transforms>
                <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
            </ds:Transforms>
            <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
            <ds:DigestValue>5JVZPTwN5Lj0sGTfFzaUeMKCo/xbCAj7fw6TLUFtZIk=</ds:DigestValue>
        </ds:Reference>
    </ds:SignedInfo>
    <ds:SignatureValue Id="value-ide34ffbff277e8d1432e864436aa11882">Mt1TUuPK3W8/0eRtJX5t45GV9bHvMjw....</ds:SignatureValue>
    <ds:KeyInfo>
        <ds:X509Data>
<ds:X509Certificate>MIIFpTCCBI2gAwIBAgIKK+...</ds:X509Certificate>
        </ds:X509Data>
    </ds:KeyInfo>
    <ds:Object>
        <xades:QualifyingProperties xmlns:xades="http://uri.etsi.org/01903/v1.3.2#" Target="#ide34ffbff277e8d1432e864436aa11882">
            <xades:SignedProperties Id="xades-id-e34ffbff277e8d1432e864436aa11882">
                <xades:SignedSignatureProperties>
                    <xades:SigningTime>2016-11-25T16:35:06Z</xades:SigningTime>
                    <xades:SigningCertificate>
                        <xades:Cert>
                            <xades:CertDigest>
                                <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
                                <ds:DigestValue>LoXZC86JwDL7zWC35qj7Q4AzrRQ=</ds:DigestValue>
                            </xades:CertDigest>
                            <xades:IssuerSerial>
                                <ds:X509IssuerName>CN=CA SINPE - PERSONA FISICA,OU=DIVISION DE SERVICIOS FINANCIEROS,O=BANCO CENTRAL DE COSTA RICA,C=CR,2.5.4.5=#130c342d3030302d303034303137</ds:X509IssuerName>
                                <ds:X509SerialNumber>207422209224813750547132</ds:X509SerialNumber>
                            </xades:IssuerSerial>
                        </xades:Cert>
                    </xades:SigningCertificate>
                    <xades:SignaturePolicyIdentifier>
                        <xades:SignaturePolicyId>
                            <xades:SigPolicyId>
                                <xades:Identifier>https://tribunet.hacienda.go.cr/docs/esquemas/2016/v4.1/Resolucion_Comprobantes_Electronicos_DGT-R-48-2016.pdf</xades:Identifier>
                            </xades:SigPolicyId>
                            <xades:SigPolicyHash>
                                <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
                                <ds:DigestValue>NmI5Njk1ZThkNzI0MmIzMGJmZDAyNDc4YjUwNzkzODM2NTBiOWUxNTBkMmI2YjgzYzZjM2I5NTZlNDQ4OWQzMQ==</ds:DigestValue>
                            </xades:SigPolicyHash>
                        </xades:SignaturePolicyId>
                    </xades:SignaturePolicyIdentifier>
                </xades:SignedSignatureProperties>
                <xades:SignedDataObjectProperties>
                    <xades:DataObjectFormat ObjectReference="#r-id-1">
                        <xades:MimeType>application/octet-stream</xades:MimeType>
                    </xades:DataObjectFormat>
                </xades:SignedDataObjectProperties>
            </xades:SignedProperties>
        </xades:QualifyingProperties>
    </ds:Object>
</ds:Signature>

Upvotes: 3

Views: 2339

Answers (2)

Sebastian
Sebastian

Reputation: 109

From what I read here and here, I stand by what I described previously: it's the hash of the node SignedProperties. This hash is part of the SignedInfo node, which is the one that gets signed afterwards. The first link is a blog in polish. It's not perfect, but Google Translate is doing a quite decent job and the info in the blog helped me to understand more clearly.

Make sure to get the node canonicalized and base64_encoded

P.S.: Suerte con la implementación que está desarrollando para la factura electrónica en Costa Rica ;-D

Upvotes: 1

Sebastian
Sebastian

Reputation: 109

I just started reading into a similar topic, so it's just an idea and I have not tried it, but I believe the second hash comes from the xades:SignedProperties node that is part of the ds:Object.

At least the id (xades-id-e34ff...) in the object and in the reference are identical.

Hope this gives you (and me :-D ) a hint.

Regards, Sebastian

Upvotes: 0

Related Questions