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An old _Discover_ article explaining RSA
I had found this article in an issue of Discover I've had for a few
years. It is a comic strip-type article by Larry Gonick article
in Layman's terms, the very basics of RSA. This article was
printed in the April 1992 issue of Discover magazine (some liberties
taken regarding pictures, etc.).
featuring SEYMOUR Cloak-and-Dagger Mathematician!
Box2:PRIME NUMBERS-numbers that can't be
broken into a product of smaller factors-
have always been one of the most amusing
and USELESS topics in mathematics.
Box3:Then why are Banks, Businesses, Mathematicians, and Government
SPY AGENCIES fighting over prime numbers?
(STOP RIGHT THERE!)
Box4:It has to do with CRYPTOGRAPHY-secret codes.
(The patriotic thing to do would be NOT to read one more word!)
Box5:In the computer age, cryptography is MATHEMATICAL: Inside the
computer, every MESSAGE is a string of ONES and
ZEROES: a number, in other words.
Box6:ENCRYPTING a message means scrambling this number,
using a reversible formula based on a secret number
or numbers called the KEY.
DECRYPTING the cyphertext is done by applying the
key in reverse.
Box7:It would seem that both the sender and receiver need to know-
and conceal-the key, but in the 1970's, WHITFIELD DIFFIE
and MARTIN HELLMAN showed a way to MAKE KEYS PUBLIC!
Box8:Knowing how to SCRAMBLE, said Diffie, is not the same as
knowing how to UNSCRAMBLE. Consider the egg!!!
Box9:Suppose a code had TWO KEYS, a scrambler and an UNSCRAMBLER...
and suppose it was IMPOSSIBLE to compute one key from
the other-in the sense that no computer could do it in less
than the lifetime of the UNIVERSE???
(crank crank crank)
Box10:You'd have an UNBREAKABLE CODE!
(Wait... Almost got it...)
Box11:It works like this:
Everyone owns a unique pair of keys. One remains private.
But the other, public key is listed in a directory.
To send me a message, you look up my public key and use
it to scramble the message.
My private key is the only way to unlock the message.
Result:total secrecy and privacy!!
Box12:Diffie's idea soon became a reality, as three guys at M.I.T.
a public-key algorithm known as RSA, from their initials.
(picture)Rivest (picture)Shamir (picture)Adleman
Box13:RSA's unbreakability depends on the "impossibility" of FACTORING
(15? that's 3 x 5! Easy!)
Box14:It's not hard to find two large PRIME NUMBERS P and Q. But if
I hand you their PRODUCT, PQ, your supercomputer will
never find P and Q again.
Box15:Under RSA, each user gets a 160 digit number, N, which is the
product of two large primes, P and Q.
Box16:The number N is made public, while P and Q remain secret. A
simple formula completes the encryption, which can't be cracked
Box17:The National Security Agency didn't like this! The spy bureau wants
the ability to crack any code!
(Your assignment Seymour: FACTOR FASTER!!)
Box18:But spies aren't the only ones who need cryptography! Anyone who
transmits ELECTRONIC DATA wants to secure the information's
(Why? What? This is an OPEN SOCIETY!)
Box19:Unbreakable public-key code would effectively
Protect money transfers from tampering
Shield sensitive business data from the competition
Immunize software against viruses
(Allow us to gossip securely by E-Mail!)
Box20:So-After years of resisting Public-Key systems, the government
in 1991 finally endorsed one as a new NATIONAL STANDARD.
(I WAS WRONG! EMBRACE ME!)
Box21:Unlike RSA, however, the government's DSA (Digital Signature
Algorithm) depends on a single, government-issue PRIME
(Take a P! Not any P!)
Box22:Within months, mathematicians had shown how this could give
the government, and the government alone, the ability to
BREAK the code-and so the argument continues...
(Trust, Where is the trust??)