I'm currently making my first cipher. What are some qualities I should strive for?
A few I've heard/thought of so far:
Changing a single bit in the input should have a 50% average chance of changing each bit of output.
The locations of flipped bits should have no pattern
Each byte should have a 1/256 chance of not changing (basically #1 ^ 8)
The number of bytes found in similar by search should be very few (I need to write down the math, but my estimate is around 5%)
Am I on the right track? What am I missing?
This is just a personal project for fun.