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

See more Belgian eHealth Platform Examples

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 for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, PublicKey, JsonArray, Http, JsonObject, Cert, Crypt2, BinData;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
jsonStr: PWideChar;
jarr: HCkJsonArray;
success: Boolean;
json: HCkJsonObject;
bdPkcs7: HCkBinData;
crypt: HCkCrypt2;
cert: HCkCert;
pubKey: HCkPublicKey;

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

http := CkHttp_Create();

jsonStr := CkHttp__quickGetStr(http,'https://api-acpt.ehealth.fgov.be/etee/v1/etks?identifier=12345678901&type=SSIN');
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

Memo1.Lines.Add(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 := CkJsonArray_Create();
success := CkJsonArray_Load(jarr,jsonStr);
if (success = False) then
  begin
    Memo1.Lines.Add('Failed to load JSON.');
    Exit;
  end;

json := CkJsonArray_ObjectAt(jarr,0);
bdPkcs7 := CkBinData_Create();
CkBinData_AppendEncoded(bdPkcs7,CkJsonObject__stringOf(json,'value'),'base64');
CkJsonObject_Dispose(json);

// Let's verify the PKCS7, and then examine the signing cert,
// and get the signing cert's public key.
crypt := CkCrypt2_Create();

// Validate the signedData PKCS7, and replace the contents of bdPkcs7 with the extracted signed content.
success := CkCrypt2_OpaqueVerifyBd(crypt,bdPkcs7);
if (success = False) then
  begin
    Memo1.Lines.Add(CkCrypt2__lastErrorText(crypt));
    Exit;
  end;

// The signed content is the DER of a certificate.
// In other words, bdPkcs7 now contains a certificate.
cert := CkCert_Create();
success := CkCert_LoadFromBd(cert,bdPkcs7);
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

// Show some certificate information:
Memo1.Lines.Add('Subject: ' + CkCert__subjectDN(cert));
Memo1.Lines.Add('Serial: ' + CkCert__serialNumber(cert));
Memo1.Lines.Add('Issuer: ' + CkCert__issuerDN(cert));

// Let's get the cert's public key...
pubKey := CkCert_ExportPublicKey(cert);
if (CkCert_getLastMethodSuccess(cert) = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

// OK, you now have the public key and can do whatever is needed..
Memo1.Lines.Add(CkPublicKey__keyType(pubKey));
Memo1.Lines.Add(IntToStr(CkPublicKey_getKeySize(pubKey)));

CkPublicKey_Dispose(pubKey);

CkHttp_Dispose(http);
CkJsonArray_Dispose(jarr);
CkBinData_Dispose(bdPkcs7);
CkCrypt2_Dispose(crypt);
CkCert_Dispose(cert);

end;