Sign a JWS with an HMAC Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetMacKey, which sets the symmetric MAC key for a signature. The key bytes are supplied in a named encoding such as hex or base64.

var
success: Boolean;
jws: HCkJws;
header: HCkJsonObject;
bIncludeBom: Boolean;
base64Key: PWideChar;
jwsCompact: PWideChar;

begin
success := False;

jws := CkJws_Create();

//  Protected header specifying HMAC-SHA256.
header := CkJsonObject_Create();
CkJsonObject_UpdateString(header,'alg','HS256');
success := CkJws_SetProtectedHeader(jws,0,header);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

bIncludeBom := False;
success := CkJws_SetPayload(jws,'This is the content to sign.','utf-8',bIncludeBom);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

//  Set the symmetric MAC key for signature 0.  The key bytes are provided in the named encoding (here
//  base64).  In production, obtain the key from a secure source rather than hard-coding it.
base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
success := CkJws_SetMacKey(jws,0,base64Key,'base64');
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;

jwsCompact := CkJws__createJws(jws);
if (CkJws_getLastMethodSuccess(jws) = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;
Memo1.Lines.Add(jwsCompact);

CkJws_Dispose(jws);
CkJsonObject_Dispose(header);