Hello a while back i bought a atsha204 encryption chip from from Sparkfun. I was going to work on a project with arduino Ethernet login. But project never happen. So some time past and got me tothink what can i do with this module/chip. This is the chip and i found a library This is it Also i found a example sketch This one . So I'm wondering what can i really use this module/chip for and one thing i was thinking was to encrypt some text message So Trying to understand how does this chip really work and how can i say for example encrypt a Hello world text and be able to display the encrypt text part of it and the not encrypt text of the hello world? Can someone please help me out from the programming side of it. Thank you.
What kind of help do you need? It sounds like you have all the resources.
Hello aarg thanks for the reply back the problem is i do not know how to program it for like a simple text how to say for example how to do a hello world text. I see in the example mac addresses and other stuff thing i have no clue what they do or how to use them to make it work. I'm a little lost.
Have you googled it?
I have seen so many thing for encrypting login to images and whatnot but not simple Hello world text. I seen a lot of it for mac addressing packet encrypting but not a simple text message.
That is sort of like saying, I know how to use a spoon, and I want to eat this avocado in front of me, but I can't. I've never seen anybody eat avocados with a spoon.
The chance that anybody on this forum has a ready to go "hello world" example for the ATSHA204 is extremely unlikely, if that didn't occur to you.
I understand there is nothing out there for I'm trying to understand how I might be able to do this from the example code i have no clue how to even start something like this. 
Learn how to break large tasks (or problems) into smaller ones. Then you can assemble the smaller, working tasks (or problems) into large working tasks, or large solved problems. 
Hello i know this is a old old project from 2015. I had to drop it for other reasons i can't remember but I'm back at it once again. I had a bunch of these sha204 security chips I looked around online sense they don't have much writing on then and found them on mouser here. I learned the pinout and tried to follow my old sketch and library but found out that the sketch is for a one wire library and that is what i use to have But these chips here are i2c and I'm not even sure that the library will work. I know the sketch won't work. So i was wondering If anyone has played with this chip in the past and found a library for it the ones i have found doesn't work. Can someone please help me out. The library is tried is from above old post very first one.
EDIT: i did a i2c scanner to see if the chip is working and Serial monitor says.
Scanning...
I2C device found at address 0x64 !
done
So the chip is working.
Joseph