Question 1 

• 01_message.mbox

my @morse = qw(
  .- -... -.-. -.. . ..-. --. .... .. .--- -.- .-.. -- -.
  --- .--.  --.- .-. ... - ..- ...- .-- -..- -.-- --..
);

my $text = "The eight letter secret token is $token ...";

$text = uc($text);
$text =~ s{([A-Z])}{$morse[ord($1) - ord('A')] . ' '}ge;
$text =~ s{[.]}{Dit}g;
$text =~ s{[-]}{Dah}g;

• Converted to email format using MIME::Lite->as_string
• Manually added 'From' line to make an mbox file
• Tested with Evolution, vim & online Morse converters