This particular text has been floating around the Internet since the eighties, I doubt that this will make any difference. Just search for "mit lockpicking filetype:pdf" and you'll find thousands of copies.
It's just text so hopefully it should be able to stay up.
However I really like backing up things and making a local mirror so I'm not going to stop you. I hate it when something interesting like this vanishes from the internet and it turns out no one has a copy.
So I'm hosting a copy of it for you and anyone else that would like to help preserve it. I just downloaded the copy with:
Edit: apparently wget has a magical flag that allows you to download all resources on an HTML page as well. Consider this solution inferior to Ellipsis753's and jamiis's. However, I will leave my reply up since this method is applicable to a lot of other situations as well.
wget -rkp -l3 -np -nH --cut-dirs=1 http://www.blurofinsanity.com/mit/lockpick.html
If on mac os you'll need to brew install wget or follow this tutorial to use curl http://psung.blogspot.com/2008/06/using-wget-or-curl-to-down...
After you've downloaded the website you can run a simple server in a terminal by navigating to where you downloaded the website and running
python -m SimpleHTTPServer
Then navigate to http://0.0.0.0:8000/lockpicking.html in your web browser.
LPT: I do this with coding tutorial sites before getting on planes so I don't waste money buying internet and time browsing other content.