user11001: I'd like to send sensor values over ethernet shield to a webserver. But for this I'd like to encrypt the data on the arduino and decrypt it on the webserver (PHP).
Do you have any suggestions or examples?

user4143: XTEA is probably your best bet.  It's lightweight, easy to implement, and secure enough for a bit of sensor data...

https://en.wikipedia.org/wiki/XTEA

There's also the slightly more complex, and also slightly more secure, XXTEA:

https://en.wikipedia.org/wiki/XXTEA


11001: <p>I'd like to send sensor values over ethernet shield to a webserver. But for this I'd like to encrypt the data on the arduino and decrypt it on the webserver (PHP).
Do you have any suggestions or examples?</p>
 4143: <p>XTEA is probably your best bet.  It's lightweight, easy to implement, and secure enough for a bit of sensor data...</p>

<ul>
<li><a href="https://en.wikipedia.org/wiki/XTEA" rel="nofollow">https://en.wikipedia.org/wiki/XTEA</a></li>
</ul>

<p>There's also the slightly more complex, and also slightly more secure, XXTEA:</p>

<ul>
<li><a href="https://en.wikipedia.org/wiki/XXTEA" rel="nofollow">https://en.wikipedia.org/wiki/XXTEA</a></li>
</ul>
