FEATURED ESSAYS 1. A Look At Public Key Encryption 2. A Look At Public Key Encryption 3. A Look At Public Key Encryptio 4. Hackers And Security. What Are Th... 5. Government Intervention On The In... 6. Security, Commerce And The Int 7. The Necessity Of Computer Securit... 8. Cryptography 9. Internet 2 10. COMPUTER SECURITY ISSUES 11. Government Intervention Of The In... 12. A Modern Day Odysseus 13. PRIVACY 14. Government Intervention Of The In...

A Look at Public Key Encryption


     Encryption is the process of disguising information by transforming
plain text into gibberish, or ciphertext, which cannot be understood by an
unauthorized person. Decryption is the process of transforming ciphertext
back into plaintext that can be read by anyone. Example of encryption can
be found in history, for example in the era of the Cold War, the Solviet
Union and the United States would send electronic messages to one military
point to another, encrypted. If the enemy intercepted the message, they
would have to crack this message to get the information. Typically when
governments used encryption they used a very complex method of encrypting
messages. Encryption does not have to be complex; the Captain Video Decoder
Rings that we had as children used encryption. You'd encode your secret
message, such as "Meet me by the swings," by replacing the letters of the
alphabet with substitute letters from a certain number of places away. For
example, let's say we decide to use the key "+4." That would mean we'd
switch each letter in our message with the letter that comes four places
later in the alphabet. D would become H; R would become V, and so on. You,
or anyone else who knows the key can easily switch the H back to a D, the V
back to an R, and figure out where to meet. Theses two examples are on
opposite sides of the spectrum, but both have their similarities and their
differences.
     The major difference complexity, the government pays mathematicians to
research complex algorithms by which to encode the messages, like the
system used by Captain Video but these algorithms are complex enough that
if you tried to crack them it would take you decades with even the most
powerful computer today. This complex mathematical code is what makes the
text secure to anyone who tries to crack it. Some similarities we can find
in these two examples are their use of the key, the unlocking instructions,
to decode the message. They only used one key to encrypt and decrypt the
messages. This creates problems, security problems. The single key must
itself be kept very secret, while somehow still being transmitted to the
person receiving encoded messages. Even if the key is transmitted safely,
which you can never know for certain, the recipient can never be sure
received messages haven't been intercepted by the enemy, altered, and
passed along to create havoc and disarray. This was a major fault of the
one key system that made it very vulnerable. The answer to this problem can
in 1976. Up until 1976 no one outside the government or at least outside
the government's control, performed any serious work in cryptography. The
National Security Agency (NSA) was in charge of all advancement of
cryptography, and that changed when a 31-year-old computer wizard named
Whitfield Diffie came up with a new system, called "public-key"
cryptography.
     Diffie tended a complicated multi-user computer system at MIT. He
became troubled with the problem of how to make the system, which held a
person's work and sometimes his or her intimate secrets, truly secure. The
traditional, top-down approach to the problem- protecting the files by user
passwords, which in turn were stored in the electronic equivalent of vaults
tended by trusted system administrators- was not satisfying. The weakness
of the system was clear: The user's privacy depended on the degree to which
the administrators were willing to protect it. Diffie recognized that the
solution rested in a decentralized system in which each person held the
literal key to his or her own privacy. He tried to get people interested in
taking on the mathematical challenge of discovering such a system, but
there were no takers. It was not until the early 1970s, when the people
running the ARPAnet were exploring security options for their members, that
Diffie decided to take it on himself. By then he was at Stanford, under the
thrall of David Kahn's work. The problem with the existing system of
cryptography was that secure information traveled over insecure channels.
In other words, a message could be intercepted before reaching its
recipient. The passing of the key Kahn realized also was a major problem.
The problem got even worse when one tried to imagine encryption employed on
a massive scale. The only way to do it, really, was to have registries, or
digital repositories, where keys would be stored. As far as Kiffie was
concerned, that system was screwed, you wound up having to trust the people
in charge of the registry. It negated the very essence of cryptography, to
maintain total privacy over your own communications.
     In May 1976, collaborating with Stanford computer scientist Martin
Hellman, Diffie cracked both problems. His scheme was called public-key
cryptography. It was a brilliant breakthrough. Every user in the system has
two keys - a public key and a private key. The public key can be widely
distributed without compromising security; the private key, however, is
held more closely than an ATM password- you don't let anyone get at it. For
relatively secret mathematical reasons, a message encoded with either key
can be decoded with the other. For instance, if I want to send you a secure
letter, I encrypt it with your public key (which I received from you), and
send you the ciphertext. You decipher it using your private key. Likewise,
if you send a message to me, you can encrypt it with my public key, and
I'll switch it back to plaintext with my private key. This principle can
also be used for authentication. Only one person can encrypt text with my
private key-me. If you can decode a message with my public key, you know
beyond a doubt that it's straight from my machine to yours. The message
bears my digital signature.
     By 1977, three members of this new community created a set of
algorithms that implemented the Diffie-Hellman scheme. Called RSA for its
founders - MIT scientists Rivest, Shamir, and Adleman-it offered
encryption that was likely to be stronger than the Data Encryption Standard
(DES), a government- approved alternative that does not use public keys.
The DES system is limited to a key size of 56 bits; RSA keys could be any
size. The larger a key is the harder it is to crack, although with the size
increase the key runs slower with size. The RSA algorithms were eventually
patented and licensed to RSA Data Security, such businesses as Apple,
Microsoft, WordPerfect, Novell, and AT&T implemented the RSA software into
there system. As the size and use of the Internet grows, the use of public
key encryption in our everyday lives will grow. The use of public key is
already found in transporting important information from computer to
computer on the Internet, such as credit card numbers. When someone
purchases something from a store on-line there card is encrypted by the
browser using the stores public key, and then sent to the store in
ciphertext, the store receives the it and then decodes with there private
key. With the age of digital communication expanding everyday the use of
public key will become part of our lives just as using an envelope has
become yesterday's way of encrypting a letter.