Delphi DLL

Create a JWS into a StringBuilder

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.CreateJwsSb, which creates a JWS and writes it into a StringBuilder.

Background. JWS (JSON Web Signature) integrity-protects a payload with a signature or MAC. The header alg names the algorithm; this example uses HMAC-SHA256 (HS256) with a symmetric MAC key.

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

begin
success := False;

jws := CkJws_Create();

//  Set the protected header for signer 0, specifying the signature algorithm (alg).
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;

//  Set the payload to be signed.
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;

//  Provide the HMAC key (base64) for signer 0.  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;

//  Create the JWS and write it into a StringBuilder.
sbJws := CkStringBuilder_Create();
success := CkJws_CreateJwsSb(jws,sbJws);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJws__lastErrorText(jws));
    Exit;
  end;
Memo1.Lines.Add(CkStringBuilder__getAsString(sbJws));

CkJws_Dispose(jws);
CkJsonObject_Dispose(header);
CkStringBuilder_Dispose(sbJws);