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BccList

property BccList: TIdEmailAddressList read write;

Example​

procedure AddBlindCopy;
var
  Msg: TIdMessage;
  Recipient: TIdEmailAddressItem;
begin
  Msg := Email;
  if Msg = nil then Exit;

  Recipient := Msg.BccList.Add;
  Recipient.Address := 'audit@example.invalid';
  Recipient.Name := 'Audit Archive';
end;

Usage​

BccList holds blind-copy recipients used by the default SMTP envelope while normal generated output deliberately suppresses the Bcc header.

Additional Technical Info​

BccList returns the live TIdEMailAddressList owned by the message. Its items identify blind-copy recipients. The message creates/frees the list; scripts must not free it or retain returned items beyond the message/action lifetime.

Assigning another list calls BccList.Assign(value) and copies entries into the existing owned collection. It does not replace ownership. Direct Add, Clear, default-index and EMailAddresses operations mutate the live list. Nil assignment is not guarded.

Envelope and header are intentionally different​

Indy's default SMTP Send(message) path copies Recipients, CCList and BccList into one envelope list and issues a recipient command for every entry. Bcc entries can therefore receive the message even though they are absent from visible message headers. Duplicates across the three lists are not deduplicated by this aggregation.

GenerateHeader removes the generated Bcc value for normal sends and direct SaveToStream. SaveToFile temporarily enables file mode and includes the encoded Bcc list in the saved header. A saved .eml can therefore disclose blind recipients; restrict access and redact before sharing it.

Suppression is not an absolute scrub: ExtraHeaders are appended later and may add a new Bcc line. Treat caller-supplied extra/raw headers as a separate disclosure surface.

NoEncode bypasses this suppression and writes raw Headers unchanged. If untrusted or previously loaded raw headers contain Bcc, setting NoEncode can expose them even when BccList itself is empty.

ProcessHeaders destructively parses raw Bcc into this list and MIME-decodes display names. Parsing/formatting is permissive and canonicalizing, not mailbox validation. ClearHeader clears the list.

The example uses a reserved .invalid address and was source-reviewed only; no SMTP operation occurred.

External references

Created 2026-07-15