(PureBasic) Get ETK Public Key (api-acpt.ehealth.fgov.be)

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The following URL returns JSON, which contains a PKCS7 signed data:

https://api-acpt.ehealth.fgov.be/etee/v1/etks?identifier=12345678901&type=SSIN

This example extracts the signed data, validates it, and then extracts the public key from the certificate (obtained from signed content in the PKCS7)

Note: The URL above uses "12345678901" which is not valid. You should replace it with a valid number.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkPublicKey.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkHttp.pb"
IncludeFile "CkJsonArray.pb"
IncludeFile "CkCrypt2.pb"
IncludeFile "CkCert.pb"
IncludeFile "CkBinData.pb"

Procedure ChilkatExample()

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

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

    jsonStr.s = CkHttp::ckQuickGetStr(http,"https://api-acpt.ehealth.fgov.be/etee/v1/etks?identifier=12345678901&type=SSIN")
    If CkHttp::ckLastMethodSuccess(http) = 0
        Debug CkHttp::ckLastErrorText(http)
        CkHttp::ckDispose(http)
        ProcedureReturn
    EndIf

    Debug jsonStr

    ; The JSON contains something like this:

    ; [
    ;     {
    ;         "key": {
    ;             "applicationIdentifier": "",
    ;             "ssin": "12345678901"
    ;         },
    ;         "value": "MIAGCSq....AAAAAAAA=="
    ;     }
    ; ]

    ; Note: The above is a JSON array (not a JSON object)
    ; It should be loaded into a Chilkat JSON array.
    jarr.i = CkJsonArray::ckCreate()
    If jarr.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkJsonArray::ckLoad(jarr,jsonStr)
    If success = 0
        Debug "Failed to load JSON."
        CkHttp::ckDispose(http)
        CkJsonArray::ckDispose(jarr)
        ProcedureReturn
    EndIf

    json.i = CkJsonArray::ckObjectAt(jarr,0)
    bdPkcs7.i = CkBinData::ckCreate()
    If bdPkcs7.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkBinData::ckAppendEncoded(bdPkcs7,CkJsonObject::ckStringOf(json,"value"),"base64")
    CkJsonObject::ckDispose(json)

    ; Let's verify the PKCS7, and then examine the signing cert,
    ; and get the signing cert's public key.
    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Validate the signedData PKCS7, and replace the contents of bdPkcs7 with the extracted signed content.
    success = CkCrypt2::ckOpaqueVerifyBd(crypt,bdPkcs7)
    If success = 0
        Debug CkCrypt2::ckLastErrorText(crypt)
        CkHttp::ckDispose(http)
        CkJsonArray::ckDispose(jarr)
        CkBinData::ckDispose(bdPkcs7)
        CkCrypt2::ckDispose(crypt)
        ProcedureReturn
    EndIf

    ; The signed content is the DER of a certificate.
    ; In other words, bdPkcs7 now contains a certificate.
    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadFromBd(cert,bdPkcs7)
    If success = 0
        Debug CkCert::ckLastErrorText(cert)
        CkHttp::ckDispose(http)
        CkJsonArray::ckDispose(jarr)
        CkBinData::ckDispose(bdPkcs7)
        CkCrypt2::ckDispose(crypt)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; Show some certificate information:
    Debug "Subject: " + CkCert::ckSubjectDN(cert)
    Debug "Serial: " + CkCert::ckSerialNumber(cert)
    Debug "Issuer: " + CkCert::ckIssuerDN(cert)

    ; Let's get the cert's public key...
    pubKey.i = CkCert::ckExportPublicKey(cert)
    If CkCert::ckLastMethodSuccess(cert) = 0
        Debug CkCert::ckLastErrorText(cert)
        CkHttp::ckDispose(http)
        CkJsonArray::ckDispose(jarr)
        CkBinData::ckDispose(bdPkcs7)
        CkCrypt2::ckDispose(crypt)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; OK, you now have the public key and can do whatever is needed..
    Debug CkPublicKey::ckKeyType(pubKey)
    Debug Str(CkPublicKey::ckKeySize(pubKey))

    CkPublicKey::ckDispose(pubKey)



    CkHttp::ckDispose(http)
    CkJsonArray::ckDispose(jarr)
    CkBinData::ckDispose(bdPkcs7)
    CkCrypt2::ckDispose(crypt)
    CkCert::ckDispose(cert)


    ProcedureReturn
EndProcedure