What is My IP Address

DES and Triple DES (3DES)
The Data Encryption Standard (DES) is a fixed-block algorithm, which is a fancy way of saying it performs a complicated math function on a standard length of bits (referred to as a block). The DES algorithm splits the blocks in two, encrypting one half using a key value and a complicated algorithm. The two halves are rejoined and then re-split; the process is repeated a number of times before the output is secure. Think of it as an extremely complicated way of shuffling bits.

Triple DES (3DES) encrypts message using three separate passes of the DES algorithm. 3DES provides a high degree of message security, but depending on processor speeds, it can take up to three times longer than standard DES to encrypt a data block. However, with the increased availability of cheap, fast processors, this method is becoming a popular option.

Digital Signature Standard
The process of encrypting and decrypting data happens through the use of keys. Without the correct key, third parties are unable to unscramble a coded message. (Of course, you can eventually crack any code given enough computing power and time.) Digital Signature Standard (DSS) uses a public key/private key pair to identify users and code and decode messages. A public key is mathematically derived from the private key using a mathematical method called factoring. A detailed explanation of factoring is beyond the scope of this website but the nature of factoring makes it nearly impossible to figure out a private key by looking at the public key.

The results of an encryption is a hash. Using a private or session key, you can code messages. The public keys ensure that the message is authentic and unchanged, and the private key decodes the message.

Diffie-Heliman Key Exchange
Understanding how DSS uses keys is oniy half the battle. You must also have a secure way to obtain session keys without any third party obtaining them, even when you exchange the keys over unsecure links. The Diffie-Hellman key exchange protocol was designed for just this purpose. The exchange is secure because keys are never transmitted in clear text, and they are exceptionally difficult to figure out. Diffie-Hellman prevents key interception using two known prime numbers that have a special mathematical relationship to one another. Is it possible for two parties to agree on a shared secret key but impossible for eavesdroppers to determine what this secret key is (even if they know the shared primes). Here is a basic example of how it works:

N = Prime number G = A Root of N
User 1 creates very large random number A.
User 2 creates very large random number B.
User 1 sends a to User 2.
User 2 sends b to User 1.
a = GA * (crazy math function using N)
b = GB * (crazy math function using N)

Both parties can now figure out the key (K) as
K = ([A]) b * (crazy math function using N)
K = ([B]) a * (crazy math function using N)