Delphi DLL

Add a Detached Signature (Header Placement Control)

Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

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Delphi DLL

var
success: Boolean;
mime: HCkMime;
pfxPassword: PWideChar;
cert: HCkCert;
transferHeaderFields: Boolean;

begin
success := False;

mime := CkMime_Create();
success := CkMime_SetBodyFromPlainText(mime,'This message will be signed.');
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;
//  Load the signing certificate (which must have access to its private key) from a PFX file.
//  The PFX password should come from a secure source rather than being hard-coded.
pfxPassword := 'myPfxPassword';
cert := CkCert_Create();
success := CkCert_LoadPfxFile(cert,'qa_data/signer.pfx',pfxPassword);
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

//  AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
//  the existing message header fields are transferred to the new outer multipart/signed entity.
transferHeaderFields := True;
success := CkMime_AddDetachedSignature2(mime,cert,transferHeaderFields);
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

success := CkMime_SaveMime(mime,'qa_output/signed.eml');
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;
Memo1.Lines.Add('Detached signature added (headers transferred).');

CkMime_Dispose(mime);
CkCert_Dispose(cert);