May 8th, 2013, 09:49 PM
Your code is basically a polyalphabetic cipher
, the most famous version of this is the vigenere cipher
It might keep secrets from your kid sister, but if your encrypted messages are somewhat longer (or there are enough encrypted messages samples), the key can be broken (it was famously broken by Charles Babbage, who later went on to pioneer the idea of the modern computer). If you look at the link I posted about the vigenere cipher above, you'll see a method on how to break it (alternatively, you could read a book called The Code Book
by Simon Singh, which goes into the development of cryptography and also shows how to break some polyalphabetic ciphers in great detail.
Up the Irons
What Would Jimi Do? Smash amps. Burn guitar. Take the groupies home.
"Death Before Dishonour, my Friends!!" - Bruce D ickinson, Iron Maiden Aug 20, 2005 @ OzzFest
Down with Sharon Osbourne