Validate a JWS Signature

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.Validate, which validates exactly one signature, identified by a zero-based index, using the key configured at that same index.

var
success: Integer;
jws: TChilkatJws;
jwsCompact: WideString;
base64Key: WideString;
v: Integer;

begin
success := 0;

jws := TChilkatJws.Create(Self);

//  Load the JWS compact serialization.
jwsCompact := 'eyJhbGciOiJIUzI1NiJ9.VGhpcyBpcyB0aGUgY29udGVudCB0byBzaWduLg.<signature>';
success := jws.LoadJws(jwsCompact);
if (success = 0) then
  begin
    Memo1.Lines.Add(jws.LastErrorText);
    Exit;
  end;

//  Provide the key for signature 0 (here an HMAC key).
base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
success := jws.SetMacKey(0,base64Key,'base64');
if (success = 0) then
  begin
    Memo1.Lines.Add(jws.LastErrorText);
    Exit;
  end;

//  Validate the signature identified by the zero-based index, using the key configured at that index.
//  Validate returns 1 when the signature or MAC is cryptographically valid, 0 when it is not, or a
//  negative value on error.
v := jws.Validate(0);
if (v < 0) then
  begin
    Memo1.Lines.Add(jws.LastErrorText);
    Exit;
  end;
if (v <> 1) then
  begin
    Memo1.Lines.Add('The signature is not valid.');
    Exit;
  end;
Memo1.Lines.Add('The signature is valid.');