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Article #21Re: Applets opening up ports for listening
From: Arunesh Mishra
Date: Thu, 02 Nov 2000 19:25
Date: Thu, 02 Nov 2000 19:25
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2669 bytes
> Remember, last class Bill mentioned that he doesn't quite
> understand why applets should be allowed to open server ports? I think I
> might have an answer. In the case of iButton applets too, there should be
> some sort of listening by the applets once they are downloaded to the
> iButton. Although, they wouldn't have TCP ports for listening, they will
> have some equivalent I guess. Otherwise, how will they know that they are
> being selected by an application?
It is essentially equivalent but more OO in nature. They have
specific methods which each applet has to implement. like select(),
deselect(), ..And the JavaCard Runtime Env. calls these methods when
the Host Application in iButton tries to communicate with the
applet.
> You can imagine a situation like that in your browser, right? You
> can download an applet in your browser, wait for other applications to
> connect to that, and then it can do some interesting things left to your
> own imagination.
> Does that make sense?
Conceptually it is very much similar. But the applet from iButton
cannot open connection to the host appliation or outside world which
is not the case with applets in browsers. Also since applets
downloaded to the iButton are custom (in the sense the user installs
it himself mostly) they being a security concern because of
opening "ports" becomes of far less concern ! But allowing applets
to open ports on browser enables many applications like multicast
audio/video conferences etc, news updates, scoreboards etc.
arunesh.
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10f190,8b9877e8e4507b52,start X-Google-Attributes: gid10f190,public X-Google-ArrivalTime: 2000-11-02 11:51:34 PST Path: arc1-ca.pugleaf.net!supernews.google.com!sn-xit-02!supernews.com!isdnet!209.249.123.233.MISMATCH!xfer10.netnews.com!netnews.com!news.maxwell.syr.edu!den-news-01.qwest.net!haven.umd.edu!cs.umd.edu!gobstopper.cs.umd.edu!arunesh From: Arunesh Mishra <arunesh@cs.umd.edu> Newsgroups: csd.cmsc818z Subject: Re: Applets opening up ports for listening Date: Thu, 2 Nov 2000 14:25:01 -0500 Organization: U of Maryland, College Park, MD 20742 Lines: 32 Message-ID: <Pine.SOL.4.21.0011021215310.11169-100000@ringding.cs.umd.edu> NNTP-Posting-Host: gobstopper.cs.umd.edu Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Trace: cronkite.cs.umd.edu 973193106 24415 128.8.126.41 (2 Nov 2000 19:25:06 GMT) X-Complaints-To: abuse@cs.umd.edu NNTP-Posting-Date: 2 Nov 2000 19:25:06 GMT To: Srinivasan Parthasarathy <sri@cs.umd.edu> In-Reply-To: <Pine.SOL.4.21.0011021117280.8296-100000@ringding.cs.umd.edu>