I think if you want the file contents to be completely UNRECOVERABLE you must.. MUST change the contents of the file to some value other that it is.. I just usually fill the file up with ZEROs until the size is the same as it orginally was. Then I delete it.
> -----Original Message----- > From: Sudarsan Raghavan [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, May 28, 2002 8:51 AM > To: Jonathan E. Paton > Cc: [EMAIL PROTECTED] > Subject: Re: Shredding a file > > > "Jonathan E. Paton" wrote: > > > > > Greetings, > > > > How would I go about shredding a file with perl, for > instance, I have a > > > > script opening a time file, writing something in there > and then deleting > > > > the temp file when execution is done. How would I go > about securely > > > > deleting the temp file afterwards so that prying eyes > can't read it afterwards? > > > > > > I am not sure I understand the question correctly, do you want to > > > delete the file only when the execution finishes. If so > add this to > > > your code > > > > > > END { > > > unlink ($your_temp_file) or "Error statement : $!\n"; > > > } > > Thanks for this explanation :-) > > > > > > > Shredding is destroying a file so throughly that nobody can > ever retrieve > > it. That means if they come along, rip out your harddisk > and scan it byte > > for byte the data cannot be recovered. unlink destroys the > reference to > > the file, not the file itself. > > > > If possible, avoid having to shred - especially for > tempories. If you > > need lots of memory, allocate and allow the operating > system to handle it. > > Usually vitally secure data isn't that large, so this isn't > a problem. > > > > If this isn't possible, encrypt the data you write to disk. > By using > > randomly generated public/private keys, you should be able > to completely > > stop prying eyes. A Quantum computer might take several > hours to crack > > good encryption, however conventional technology will take > many years. > > > > In VERY security critical enviroments, turn off swap files > - they aren't > > particularly safe either. Remember a vital aspect of > computer security: > > > > Never rely totally on software based security. There is no point > > installing/writing lots of security software if your > system admin is > > a KGB agent, or your cleaner can access your computer system. > > > > EVERY computer can be cracked with physical access. > > > > Jonathan Paton > > > > ===== > > $_=q|.,&@$$. ,.@$&@$. .&$$@. ,,$ ....!$_=$p.'&$@.',y'&$@' > .,';for(/\S+/g){ > > !|.q| .$ .,@, ,$, .,.. @, ,$ ,,@ > .,,.!++$.<22?${'y'.$_}=chr$.+64:[$$=${'y' > > !|.q| ,@$@&.,. $$$&, ..@&&$,,, $., > ..!.$_},$y.=($.=~/22\|26\|3(3\|7)/x?' ' > > !|.q|. @ ., ,.&,,, , .$..&. .,$ .,,!.$$:"\l$$")]};$y=~/ > (.*)/;warn"$1\n" > > !|.q|. $ .,. .,$$&&$...&., @.,.&@$@ > .|,map{-$|--?$r:$p.=$_}split'!';eval$r > > > > __________________________________________________ > > Do You Yahoo!? > > Everything you'll ever need on one web page > > from News and Sport to Email and Music Charts > > http://uk.my.yahoo.com > > > > -- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > -- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > ---------------------------------------------------------------------------- -------------------- The views and opinions expressed in this email message are the sender's own, and do not necessarily represent the views and opinions of Summit Systems Inc. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
