Delphi ActiveX

Load an EC Public Key from Point Coordinates

Demonstrates the Chilkat PublicKey.LoadEcdsa method, which loads an elliptic-curve public key from its affine point coordinates. The first argument names the curve, the second is the hexadecimal x-coordinate (Qx), and the third is the y-coordinate (Qy).

Background: An EC public key is a point (x, y) on a named curve, so this loader constructs the key from those raw values directly — the option to use when a system hands you the coordinates rather than an encoded key. The curve name (for example secp256r1) is essential, since the same coordinates mean nothing without knowing which curve they lie on.

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var
success: Integer;
pubKey: TPublicKey;
curveName: WideString;
qx: WideString;
qy: WideString;

begin
success := 0;

//  Demonstrates the PublicKey.LoadEcdsa method, which loads an elliptic-curve public key from its
//  affine point coordinates.  The 1st argument names the curve, the 2nd is the hex x-coordinate
//  (Qx), and the 3rd is the hex y-coordinate (Qy).

pubKey := TPublicKey.Create(Self);

curveName := 'secp256r1';
qx := '1ccbe91c075fc7f4f033bfa248db8fccd3565de94bbfb12f3c59ff46c271bf83';
qy := 'ce4014c68811f9a21a1fdb2c0e6113e06db7ca93b7404e78dc7ccd5ca89a4ca9';

success := pubKey.LoadEcdsa(curveName,qx,qy);
if (success = 0) then
  begin
    Memo1.Lines.Add(pubKey.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Loaded an EC public key on ' + curveName);