Project 4
Start the paperwork now to get your instructional computing account to hold your WWW pages.
Do not wait until the last minute, as other people have to do things for you.
(1) Go to the sinc site in main library and ask for an ic account. Takes about 24 hours.
(2) Afterwards, send email to webmaster@ic.sunysb.edu to request a place to put your WWW pages.
(3) Once this is set up, use ftp to transfer your files, eg. `ftp libws1.ic.sunysb.edu ', login, and `put filename.htm'
Computer Security and Ethics
As computers and networks become more important, security and ethical issues continually arise.
There is a difference between unethical and illegal behavior. Ethics govern how people should behave, Laws in some sense how they must behave.
There is a so-called ``hacker ethic'', which suggests that information should be free, and there should be no restriction on how people use computers or information.
Although there are good things in this view, the issues get very complicated. Genuinely criminal or unethical behavior sometimes follows in the guise of this belief.
Viruses
A virus is a program which infects other programs.
Viruses typically consist of two parts. One part controls reproduction, spreading itself by copying onto floppy disks or email. The other part does something nasty or harmless to the computer system it is on.
Typically viruses infect the operating system of the computer, which control everything, hence the possibility of serious damage.
Initially, hackers created viruses to learn how they can be done, but now it is mostly vandelism, eg. the Internet Worm and the Michaelangelo virus.
Antivirus programs look for changes in operating system files, like their size or content, and use them to identify viruses.
To guard against viruses, be careful about where you accept disks or software from.
Encryption
Encryption is an important technology to protect information stored on computers.
An encryption algorithm takes data and a secret key, and scrambles it so that the resulting information cannot be reconstructed without the key.
Secret codes have been used since the times of Julius Caesar.
Indeed, the simple algorithm of replacing letters with shifted letters
( 
, 
, ...) is called a Caesar shift.
Abj gung jr unir na rssvpvrag rapbqvat grpuavdhr, jung pna jr qb jvgu vg?
Such simple codes can easily be broken by computers, or clever people.
``Now that we have an efficient encoding technique, what can we do with it?''
A more powerful encryption algorithm is DES, the old government-approved data encryption standard. With only a 56-bit key, there was always a suspicion that it was designed to be weak enough for only the NSA to break.
A stronger proposed standard, Clipper, requires that keys be kept in `escrow', and available to the government with a court order.
Ethical Issues in Encryption
The government forbids export of computer systems with strong encryption software, for fear it will be used by hostle countries and groups.
Should cryptography strong enough so law enforcement authorities cannot break it be permitted? Court-ordered wiretaps are an important part of investigations, but can become useless with encrypted voice lines.
Public key cryptography
One of the hardest things in using cryptography is to send someone the key to decrypt it, since by definition it must be sent unencrypted.
In public key cryptography, there are two keys, one for encoding and one for decoding. Amazingly, knowing the encoding key will not help in decoding it, so this solves the key transfer problem.
A similar technology is emerging for digital signatures. If you and I agree on a contract over email, how can we `sign it'. If we later have a disagreement, your printing out the email with the contract won't convince me, since you might have edited the text before printing it.
A digital signature is an encrypted version of the document, which goes along with the unencrypted version. This encrypted version also contains the time and date of the file. You cannot modify the document without the write password, and so can later decrypt it to prove it is unchanged.
Software Piracy
Another important ethical problem concerns software piracy. It is often much cheaper to copy software than buy it.
Some software companies use copy-protection schemes, but these are clumsy for honest users as well as thieves.
As software piracy became an important issue, companies and universities have started complying to a much greater extent than before.
Network copies enable companies to buy software which can be used throughout large organizations, better justifying the price.
Shareware is software which is given away with the understanding that people who use it should pay. This works surprisingly well on a small scale, but is not a solution for large systems.
Public domain software is software which may be copied freely. There is much good stuff, but watch for viruses!
Test cases for computer ethics
What do you think about the following ethical issues in computing, page 13.21 in the text?