(PureBasic) Verify a CAdES-BES Signature and Examine Signature Contents

Demonstrates how to validate a .p7m (.p7s) signature and examine the contents of the signature.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkDtObj.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

    ; This example requires 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

    outputFile.s = "qa_output/original.xml"
    inFile.s = "qa_data/p7m/fattura_signature.xml.p7m"

    ; Verify the signature and extract the contained file, which in this case is XML.
    success.i = CkCrypt2::ckVerifyP7M(crypt,inFile,outputFile)
    If success = 0
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkCrypt2::ckDispose(crypt)
        ProcedureReturn
    EndIf

    Debug "Signature validated."

    ; Now let's examine the information about the signature.
    json.i = CkCrypt2::ckLastJsonData(crypt)
    If CkCrypt2::ckLastMethodSuccess(crypt) = 0
        ; This should never be the case...
        Debug "No information available."
        CkCrypt2::ckDispose(crypt)
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(json, 0)
    Debug CkJsonObject::ckEmit(json)

    ; Here's an example of the information about the signature:
    ; {
    ;   "pkcs7": {
    ;     "verify": {
    ;       "certs": [
    ;         {
    ;           "issuerCN": "Xyz EU Qualified Certificates CA G1",
    ;           "serial": "99A28A51AC389999"
    ;         }
    ;       ],
    ;       "useConstructedOctets": true,
    ;       "digestAlgorithms": [
    ;         "sha256"
    ;       ],
    ;       "signerInfo": [
    ;         {
    ;           "cert": {
    ;             "subjectKeyIdentifier": "5VM4x8AWnXf07yzbXuLtbb0U3yY=",
    ;             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
    ;             "digestAlgName": "SHA256"
    ;           },
    ;           "signingAlgOid": "1.2.840.113549.1.1.11",
    ;           "signingAlgName": "RSA-SHA256-PKCSV-1_5",
    ;           "authAttr": {
    ;             "1.2.840.113549.1.9.3": {
    ;               "name": "contentType",
    ;               "oid": "1.2.840.113549.1.7.1"
    ;             },
    ;             "1.2.840.113549.1.9.5": {
    ;               "name": "signingTime",
    ;               "utctime": "190901152340Z"
    ;             },
    ;             "1.2.840.113549.1.9.4": {
    ;               "name": "messageDigest",
    ;               "digest": "y+gd/zAQK33A//HInhaZba7w1fUJleV9AHbP1Ntx6U0="
    ;             },
    ;             "1.2.840.113549.1.9.16.2.47": {
    ;               "name": "signingCertificateV2",
    ;               "der": "MIH4MI..w4vv0="
    ;             }
    ;           }
    ;         }
    ;       ]
    ;     }
    ;   }
    ; }

    ; Use this online tool to generate parsing code from sample JSON: 
    ; Generate Parsing Code from JSON

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

    issuerCN.s
    serial.s
    strVal.s
    certSubjectKeyIdentifier.s
    certDigestAlgOid.s
    certDigestAlgName.s
    signingAlgOid.s
    signingAlgName.s
    authAttrContentTypeName.s
    authAttrContentTypeOid.s
    authAttrSigningTimeName.s
    authAttrMessageDigestName.s
    authAttrMessageDigestDigest.s
    authAttrSigningCertificateV2Name.s
    authAttrSigningCertificateV2Der.s

    i.i = 0
    count_i.i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.certs")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        issuerCN = CkJsonObject::ckStringOf(json,"pkcs7.verify.certs[i].issuerCN")
        serial = CkJsonObject::ckStringOf(json,"pkcs7.verify.certs[i].serial")
        i = i + 1
    Wend
    i = 0
    count_i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.digestAlgorithms")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        strVal = CkJsonObject::ckStringOf(json,"pkcs7.verify.digestAlgorithms[i]")
        i = i + 1
    Wend
    i = 0
    count_i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.signerInfo")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        certSubjectKeyIdentifier = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.subjectKeyIdentifier")
        certDigestAlgOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.digestAlgOid")
        certDigestAlgName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.digestAlgName")
        signingAlgOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signingAlgOid")
        signingAlgName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signingAlgName")
        authAttrContentTypeName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.3" + Chr(34) + ".name")
        authAttrContentTypeOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.3" + Chr(34) + ".oid")
        authAttrSigningTimeName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.5" + Chr(34) + ".name")
        CkJsonObject::ckDtOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.5" + Chr(34) + ".utctime",0,authAttrSigningTimeUtctime)
        authAttrMessageDigestName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.4" + Chr(34) + ".name")
        authAttrMessageDigestDigest = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.4" + Chr(34) + ".digest")
        authAttrSigningCertificateV2Name = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.16.2.47" + Chr(34) + ".name")
        authAttrSigningCertificateV2Der = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.16.2.47" + Chr(34) + ".der")
        i = i + 1
    Wend

    CkJsonObject::ckDispose(json)



    CkCrypt2::ckDispose(crypt)
    CkDtObj::ckDispose(authAttrSigningTimeUtctime)


    ProcedureReturn
EndProcedure