Delphi DLL Requires Chilkat v11.0.0+

JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

Creates a JSON Web Signatures (JWS) using HMAC SHA-256. Delphi DLL

var
success: Boolean;
jwsProtHdr: HCkJsonObject;
jws: HCkJws;
hmacKey: PWideChar;
signatureIndex: Integer;
bIncludeBom: Boolean;
payloadStr: PWideChar;
jwsCompact: PWideChar;
jws2: HCkJws;
v: Integer;
joseHeader: HCkJsonObject;

begin
success := False;

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

//  First create the JWS Protected Header
jwsProtHdr := CkJsonObject_Create();
CkJsonObject_AppendString(jwsProtHdr,'typ','JWT');
CkJsonObject_AppendString(jwsProtHdr,'alg','HS256');
Memo1.Lines.Add('JWS Protected Header: ' + CkJsonObject__emit(jwsProtHdr));

//  Output:
//  JWS Protected Header: {"typ":"JWT","alg":"HS256"}

jws := CkJws_Create();

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

//  Set the protected header:
CkJws_SetProtectedHeader(jws,signatureIndex,jwsProtHdr);

//  Set the payload.
bIncludeBom := False;
payloadStr := 'In our village, folks say God crumbles up the old moon into stars.';
CkJws_SetPayload(jws,payloadStr,'utf-8',bIncludeBom);

//  Create the JWS
//  By default, the compact serialization is used.
jwsCompact := CkJws__createJws(jws);
if (CkJws_getLastMethodSuccess(jws) = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

Memo1.Lines.Add('JWS: ' + jwsCompact);

//  sample output:
//  JWS: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

//  Now load the JWS, validate, and recover the original text.
jws2 := CkJws_Create();

//  Load the JWS.
success := CkJws_LoadJws(jws2,jwsCompact);

//  Set the MAC key used for validation.
signatureIndex := 0;
CkJws_SetMacKey(jws2,signatureIndex,hmacKey,'base64url');

//  Validate the 1st (and only) signature at index 0..
v := CkJws_Validate(jws2,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(jws2));
    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(CkJws__getPayload(jws2,'utf-8'));

//  Examine the protected header:

joseHeader := CkJsonObject_Create();
success := CkJws_GetProtectedH(jws2,signatureIndex,joseHeader);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws2));
    Exit;
  end;

CkJsonObject_putEmitCompact(joseHeader,False);

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

//  Output:

//  	Signature validated.
//  	In our village, folks say God crumbles up the old moon into stars.
//  	Protected (JOSE) header:
//  	{ 
//  	  "typ": "JWT",
//  	  "alg": "HS256"
//  	}

CkJsonObject_Dispose(jwsProtHdr);
CkJws_Dispose(jws);
CkJws_Dispose(jws2);
CkJsonObject_Dispose(joseHeader);