Delphi ActiveX

Export a Public Key as DER into a BinData

Demonstrates the Chilkat PublicKey.GetDerBd method, which writes the public key as binary DER into a BinData. The first argument selects the representation (as for GetPem) and the second is the BinData that receives the bytes (its contents are replaced).

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: The in-memory binary export: the raw DER lands in a BinData ready to hash, transmit, or hand to another API without a temporary file. It is the BinData counterpart to the text exporters, and the first argument picks the same PKCS #1 versus SubjectPublicKeyInfo structure.

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var
success: Integer;
pubKey: TPublicKey;
preferPkcs1: Integer;
bd: TChilkatBinData;

begin
success := 0;

//  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
//  JWK, and other supported representations.
pubKey := TPublicKey.Create(Self);
success := pubKey.LoadFromFile('qa_data/public.pem');
if (success = 0) then
  begin
    Memo1.Lines.Add(pubKey.LastErrorText);
    Exit;
  end;

//  Write the public key as binary DER into a BinData.  The 1st argument selects the representation
//  (as for GetPem) and the 2nd is the BinData that receives the bytes (its contents are replaced).
preferPkcs1 := 0;
bd := TChilkatBinData.Create(Self);
success := pubKey.GetDerBd(preferPkcs1,bd.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(pubKey.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add('Exported ' + IntToStr(bd.NumBytes) + ' DER bytes.');