Delphi DLL

Export a Public Key as a JWK

Demonstrates the Chilkat PublicKey.GetJwk method, which returns the public key as a compact JWK (JSON Web Key). It takes no arguments; binary values use Base64url without padding and the member order is stable across calls.

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: JWK is the JSON key format used across modern web security — JWT, OAuth, OpenID Connect. Exporting a public key to JWK is exactly what you do to publish it in a JWK Set (a jwks_uri endpoint) so others can verify your signatures. The stable member order matters because it makes the output reproducible, which is important when the JWK feeds into a thumbprint.

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var
success: Boolean;
pubKey: HCkPublicKey;
jwk: PWideChar;

begin
success := False;

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

//  Export the public key as a compact JWK (JSON Web Key).  Binary values use Base64url without
//  padding, and the member order is stable across calls.
jwk := CkPublicKey__getJwk(pubKey);
if (CkPublicKey_getLastMethodSuccess(pubKey) = False) then
  begin
    Memo1.Lines.Add(CkPublicKey__lastErrorText(pubKey));
    Exit;
  end;
Memo1.Lines.Add(jwk);

CkPublicKey_Dispose(pubKey);