Delphi DLL Requires Chilkat v11.0.0+

Validate JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) using HMAC SHA-256. Delphi DLL

var
success: Boolean;
jws: HCkJws;
hmacKey: PWideChar;
signatureIndex: Integer;
jwsCompact: PWideChar;
v: Integer;
joseHeader: HCkJsonObject;

begin
success := False;

//  This requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  This example takes a JSON signature in compact serialization format,
//  and uses a MAC key to validate and recover the protected header and payload.

jws := CkJws_Create();

//  Set the HMAC key:
hmacKey := 'AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow';
signatureIndex := 0;
CkJws_SetMacKey(jws,signatureIndex,hmacKey,'base64url');

//  Load the JWS.
jwsCompact := 'eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk';
success := CkJws_LoadJws(jws,jwsCompact);

//  Validate the 1st (and only) signature at index 0..
v := CkJws_Validate(jws,signatureIndex);
if (v < 0) then
  begin
    //  Perhaps Chilkat was not unlocked or the trial expired..
    Memo1.Lines.Add('Method call failed for some other reason.');
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;
if (v = 0) then
  begin
    Memo1.Lines.Add('Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.');
    Exit;
  end;

//  If we get here, the signature was validated..
Memo1.Lines.Add('Signature validated.');

//  Recover the original content:
Memo1.Lines.Add('Recovered content:');
Memo1.Lines.Add(CkJws__getPayload(jws,'utf-8'));

//  Examine the protected header:

joseHeader := CkJsonObject_Create();
success := CkJws_GetProtectedH(jws,signatureIndex,joseHeader);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

CkJsonObject_putEmitCompact(joseHeader,False);

Memo1.Lines.Add('Protected (JOSE) header:');
Memo1.Lines.Add(CkJsonObject__emit(joseHeader));

//  Output:

//  	Signature validated.
//  	Recovered content:
//  	{"iss":"joe",
//  	 "exp":1300819380,
//  	 "http://example.com/is_root":true}
//  	Protected (JOSE) header:
//  	{ 
//  	  "typ": "JWT",
//  	  "alg": "HS256"
//  	}

CkJws_Dispose(jws);
CkJsonObject_Dispose(joseHeader);