2 good functions for encrypting and decrypting files

2 good functions for encrypting and decrypting files

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    function Decryptfile(directory as string, Filename as string)
	local filechars as integer
	local filenamechars as string
	
	set dir directory
	seed=123456789
	open to read 1,filename
	randomize seed	
	filechars=len(filename)
	filenamechars=left$(filename,filechars-4)
	open to write 2,filenamechars
	c=file size (filename)
		for i=1 to c
			read byte 1,d
			d=d-rnd(256)
			if d<0
   			d=d+256
			endif
			write byte 2,d
		next i
		close file 1
		close file 2
		delete file filename
	set dir ".."
endfunction
function Encryptfile(directory as string, Filename as string)
	set dir directory
	seed=123456789
	open to read 1,filename
	randomize seed
	open to write 2,filename+".dat"
	a=file size(filename)
	for i=1 to a
		read byte 1,b
		b=b+rnd(256)
		if b>256
   		b=b-256
		endif
		write byte 2,b
	next i
	close file 1
	close file 2
	delete file filename
	set dir ".."
endfunction