Validate a JWS with a Public Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetPublicKey, which sets the public key used to validate a signature of a loaded JWS.

The file path is relative to the application's current working directory. An absolute path may also be used. Supply the path appropriate to your own environment.

var
success: Boolean;
jws: HCkJws;
jwsCompact: PWideChar;
pubKey: HCkPublicKey;
v: Integer;

begin
success := False;

jws := CkJws_Create();

//  Load the JWS compact serialization.
jwsCompact := 'eyJhbGciOiJIUzI1NiJ9.VGhpcyBpcyB0aGUgY29udGVudCB0byBzaWduLg.<signature>';
success := CkJws_LoadJws(jws,jwsCompact);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

//  The file path is relative to the application's current working directory.  An absolute path
//  may also be used.  Supply the path appropriate to your own environment.
//  Load the signer's public key and set it for validating signature 0.
pubKey := CkPublicKey_Create();
success := CkPublicKey_LoadFromFile(pubKey,'qa_data/signer_pubkey.pem');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPublicKey__lastErrorText(pubKey));
    Exit;
  end;
success := CkJws_SetPublicKey(jws,0,pubKey);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

//  Validate the signature.  Validate returns 1 when valid, 0 when not, or a negative value on error.
v := CkJws_Validate(jws,0);
if (v < 0) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;
if (v <> 1) then
  begin
    Memo1.Lines.Add('The signature is not valid.');
    Exit;
  end;
Memo1.Lines.Add('The signature is valid.');

CkJws_Dispose(jws);
CkPublicKey_Dispose(pubKey);