Stephen Sutter
Wdim415 – Terry Lunn
Diffie/Hellman Key Exchange
September 14th, 2011
The Diffie-Hellman key exchange was developed by Whitfield Diffie and Stanford
Hellman in 1976. This technique allows two users to exchange a secret key over an
insecure medium without any prior secrets. To explain this conceptually, the two parties
involved in creating the encryption have to select a prime number and an integer
number together, so party 1 selects prime number 13, and integer 6, and party 2 also
selects these same numbers. Now, both parties must select a random secret number,
so party 1 will select 3, which party 1 won’t let party 2 know about, and party 2 will do
the same, selecting number 10. Ok, now for them to generate the first public key (which
will be sent over to party 2), party 1 will take the integer number (6) and raise it to the
power of her random secret number which is 3, and then that total (6^3) will be divided
by the Prime number (13), so this will equal 8. Now party 1’s public key is 8, and is sent
over to party 2. Now, party 2 will do exactly what party 1 did to get a public key, so he
will take the integer number 6 and raise it to the power of his random secret number
which is 10, then that total is divided by the prime number 13 once again, which equals
4. Now if both parties do the equation once again but with each other’s sums of the
previous equation results, they will both get identical secret keys. So party 1 will take
party 2’s sum of 4 and put into the equation once again which would be 4 raised to the
power of 3, and then divided by 13, and her sum of this equation would be 12. Party 2
will get the same result when he uses party 1’s previous sum (8). This Diffie-Hellman
ecryption technique was ground breaking for its time and is still used together because
it is so hard to crack. In order for somebody to actually crack a code between two
parties, there would have to be a third discrete party involved, intercepting the exchange
of the Prime and Integer numbers between party 1 and 2.