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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_v9_5_0_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: TChilkatHttp;
jsonStr: WideString;
jarr: TChilkatJsonArray;
success: Integer;
json: IChilkatJsonObject;
bdPkcs7: TChilkatBinData;
crypt: TChilkatCrypt2;
cert: TChilkatCert;
pubKey: IPublicKey;

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

http := TChilkatHttp.Create(Self);

jsonStr := http.QuickGetStr('https://api-acpt.ehealth.fgov.be/etee/v1/etks?identifier=12345678901&type=SSIN');
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    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 := TChilkatJsonArray.Create(Self);
success := jarr.Load(jsonStr);
if (success = 0) then
  begin
    Memo1.Lines.Add('Failed to load JSON.');
    Exit;
  end;

json := jarr.ObjectAt(0);
bdPkcs7 := TChilkatBinData.Create(Self);
bdPkcs7.AppendEncoded(json.StringOf('value'),'base64');

// Let's verify the PKCS7, and then examine the signing cert,
// and get the signing cert's public key.
crypt := TChilkatCrypt2.Create(Self);

// Validate the signedData PKCS7, and replace the contents of bdPkcs7 with the extracted signed content.
success := crypt.OpaqueVerifyBd(bdPkcs7.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

// The signed content is the DER of a certificate.
// In other words, bdPkcs7 now contains a certificate.
cert := TChilkatCert.Create(Self);
success := cert.LoadFromBd(bdPkcs7.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

// Show some certificate information:
Memo1.Lines.Add('Subject: ' + cert.SubjectDN);
Memo1.Lines.Add('Serial: ' + cert.SerialNumber);
Memo1.Lines.Add('Issuer: ' + cert.IssuerDN);

// Let's get the cert's public key...
pubKey := cert.ExportPublicKey();
if (cert.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

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