Transferring ciphers as e-mail
A frequent source of confusion for
recipients of academic signature ciphers via e-mail is an insane
treatment by some mailers or the apple OS of mail-attached
files. Mailers or the apple OS at the
receiving side may rearrange or remove bytes(e.g. arbitrarily
removing the byte Ox0d) in mail attachments
without prompting the user for awareness let alone for consent.
Of course this defacement renders attached ciphers undecipherable.
The mailer or
the apple OS have no idea what they are dealing with, yet they
may decide to rearrange or delete bytes. What do IT-people think
when coding this junk behavior !???
If necessary, the sender can prevent that with the quick fix
of sending ciphers in a zip archive as container. Zip archives are
usually respected as binary files at the receiving side and are
spared from defacement by the mail program or the apple OS,
A more convenient but dirtier fix may be to give
the cipher the name extension ".png" or ".mp3" or possibly
other media type's extensions. Any common compressed format will
be sensitive to arbitrary editing and will probably be protected
from mailer/OS infringement. Selecting these extensions will
usually trick the mailer(or the apple OS) into keeping it's sticky
fingers off the attachment and not e.g. steal the carriage
On your first cryptographically protected contact
with an apple or windows user, it is recommended you
explicitly sign your cipher. Furthermore you should inform the
recipient about the potential problem with attachment
alterations. Few people are aware of such mailer/OS assaults.
The recipient can then detect if the cipher has been defaced and
request a retransmission in a form that is protected from
mailer/OS infringement at the receiving side.
Changing such aberrant mailer/OS behavior is
beyond my potential, so I regret that inconvenient workarounds
might be necessary.
Signatures and time stamps are human readable text. They are
insensitive to the annoying mailer/OS infringements.
On a Linux, mailers always seem to behave reasonably and leave
attachments alone by default.