Set a Per-Recipient JWE Header

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetRecipientHeader, which sets the per-recipient unprotected header for a recipient index.

var
success: Boolean;
jwe: HCkJwe;
header: HCkJsonObject;
base64Key: PWideChar;
recipHeader: HCkJsonObject;
sbContent: HCkStringBuilder;
sbJwe: HCkStringBuilder;

begin
success := False;

jwe := CkJwe_Create();

//  Protected header: AES key-wrap with AES-256-GCM content encryption.
header := CkJsonObject_Create();
CkJsonObject_UpdateString(header,'alg','A256KW');
CkJsonObject_UpdateString(header,'enc','A256GCM');
success := CkJwe_SetProtectedHeader(jwe,header);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;

//  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
//  secure source rather than hard-coding it.
base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
success := CkJwe_SetWrappingKey(jwe,0,base64Key,'base64');
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;

//  Set the per-recipient unprotected header for recipient 0, for example a key id used to identify
//  which key a recipient should use.
recipHeader := CkJsonObject_Create();
CkJsonObject_UpdateString(recipHeader,'kid','recipient-key-1');
success := CkJwe_SetRecipientHeader(jwe,0,recipHeader);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;

sbContent := CkStringBuilder_Create();
CkStringBuilder_Append(sbContent,'This is the secret content.');
sbJwe := CkStringBuilder_Create();
success := CkJwe_EncryptSb(jwe,sbContent,'utf-8',sbJwe);
if (success = False) then
  begin
    Memo1.Lines.Add(CkJwe__lastErrorText(jwe));
    Exit;
  end;
Memo1.Lines.Add(CkStringBuilder__getAsString(sbJwe));

CkJwe_Dispose(jwe);
CkJsonObject_Dispose(header);
CkJsonObject_Dispose(recipHeader);
CkStringBuilder_Dispose(sbContent);
CkStringBuilder_Dispose(sbJwe);