Lines Beginning with "From" Dash-Escaped?

John A. Martin
Sat Apr 28 16:48:01 2001

Hash: SHA1

>>>>> "IK" == Ingo Klöcker
>>>>> "Re: Lines Beginning with "From" Dash-Escaped?"
>>>>> Sat, 28 Apr 2001 11:42:10 +0200
>> Can anyone expand on the reasons why PGP and GPG use the >> dash-escape in this manner, aside from what is written in the >> RFC? IK> I found this in the NEWS: IK> Noteworthy changes in version 0.9.0 IK> ----------------------------------- [snip] IK> * New option --escape-from-lines to "dash-escape" "From " IK> lines to IK> prevent mailers to change them to ">From ". This is IK> not enabled by default because it is not in compliance IK> with rfc2440 - however, you should turn it on. IK> Reason: If a MUA uses the mailbox format, i.e. a simple text IK> file where all messages are stored one after the other a line IK> starting with "From " is used to mark the start of the next IK> message. There are a lot of MUAs which use the mailbox format, IK> for example Netscape Messenger, KMail and also Pine and Mutt. IK> Now if a line inside a message starts with "From " it will be IK> changed to ">From " by the MUA while receiving the mail. But IK> this additional ">" would break the signature. Therefore PGP IK> and GnuPG dash-escape the "From " if they clear-sign messages. The crux of the matter is that many MTAs will escape leading From-space during local delivery. IK> The reason why you never have seen a line beginning with IK> ">From " might be because the MUA automatically removes the IK> ">" before displaying the mail. The ">" can only be found in IK> the mailbox file in which the message is stored. Also, some local delivery agents are smart enough to only escape the From-space if it is preceded by a blank line and the remainder of the line "looks like" a mailbox delimiter. Moreover, more and more mail systems are being optioned not to use the Berkeley style mailbox that uses a From-space line to delimit mail messages. jam -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.4 (GNU/Linux) Comment: OpenPGP encrypted mail preferred. See <> iEYEARECAAYFAjrq1/cACgkQUEvv1b/iXy/9jgCggs+myJoAOh5XlNui5PzksN8W dhsAoIBAjs4tXJ23XZolAaFNNahMi4uF =xSoa -----END PGP SIGNATURE-----