Message Crypt Example

module MsgCrypt

def self.encode(msg)
print "\n\n"
$result = ""
msg.each_byte{|x|
$i = x * 3 + 18
print "#{x.chr} => #{$i}\n"
$result << "#{$i},"
}
return $result
end
def self.decode(msgtable)
print "\n\n"
$result = ""
msgtable.each{|x|
$i = (x -18) / 3
print "#{x} => #{$i.chr}\n"
$result << "#{$i.chr}"
}
return $result
end

def self.save_to_file(x)
 file = File.open('result.txt', 'wb')
 file.write(x)
 file.close
end

def self.read_key
print "=============================================================\n"
print "NARZEW MESSAGE ENCRYPTER/DECRYPTER v 1.0\n"
print "Copyright 2012 Narzew\n"
print "=============================================================\n"
print "If you decrypt a message, add bytes to $code array :)\n"
print "=============================================================\n"
print "Type the running mode.\n"
print "0 - encrypt\n"
print "1 - decrypt\n"
print "=============================================================\n"
mode = gets.chomp
case mode.to_i
when 0 then $mode = 0
when 1 then $mode = 1
else
print "=============================================================\n"
print "Invalid Mode. Press ENTER to EXIT.\n"
print "=============================================================\n"
$stdin.gets
exit
end
print "=============================================================\n"
print "Type the file with the message to encrypt.\n" if $mode == 0
print "Type the file with the message to decrypt.\n" if $mode == 1
print "=============================================================\n"

$filename = gets.chomp!
if File.exist?($filename)
file = File.open($filename, 'rb')
$a = file.read
file.close
else
print "=============================================================\n"
print "File do not exist.\n"
print "Press ENTER to close.\n"
print "=============================================================\n"
$stdin.gets
exit
end

if $mode == 0
$msg = $a
MsgCrypt.save_to_file("$code=[" + MsgCrypt.encode($msg) + "]")
elsif $mode == 1
eval($a)
MsgCrypt.save_to_file(MsgCrypt.decode($code))
end

rescue

print "=============================================================\n"
print "Fail to encrypt or decrypt the data.\n"
print "PRESS ENTER TO EXIT.\n"
print "=============================================================\n"
$stdin.gets
exit

end

def self.make_footer
print "=============================================================\n"
 print "MESSAGE ENCRYPTED.\nALSO CHECK result.txt ;)\n" if $mode == 0
 print "MESSAGE DECRYPTED.\nALSO CHECK result.txt ;)\n" if $mode == 1
 print "Press ENTER to exit.\n"
print "=============================================================\n"
 $stdin.gets
end

def self.do
 MsgCrypt.read_key
 MsgCrypt.make_footer
end

end

begin

MsgCrypt.do

rescue => e

print "\n=============================================================\n"
print "Fatal error : #{e}\n"
print "Press ENTER to exit.\n"
print "=============================================================\n"
$stdin.gets

end