Your enthusiasm is encouraging, just keep in mind the standard warning that crypto is very easy to do wrong (and wrong in a way that's hard to detect until your platform is blown wide open, see e.g. the PS3 root key disaster). In particular, a ton of academics argue that encryption (e.g. vanilla AES) by itself isn't very useful, and authenticated encryption [1] should be the default offered to standard users. There are multiple ways to achieve this, your hardware may support AE modes like GCM or others.
Keep in mind that crypto's only half the battle, and even "perfectly valid" crypto can still leave your platform vulnerable to things like replay attacks [2]. e.g. lets say someone uses your board as a doorbell: a crafty attacker can sniff the doorbell packet and replay it constantly if you don't use something like a request counter.
Point is: you shouldn't make your users cobble those steps together, they'll get them wrong. You're in fact very likely to get them wrong yourself, if (as you say) you're still learning the ins and outs of crypto. I wish you the best of luck, but keep in mind that you have a long journey ahead of you. I'd particularly recommend you complete the Matasono crypto challenge [3] before you even think of trying your hands on raw crypto primitives.
Keep in mind that crypto's only half the battle, and even "perfectly valid" crypto can still leave your platform vulnerable to things like replay attacks [2]. e.g. lets say someone uses your board as a doorbell: a crafty attacker can sniff the doorbell packet and replay it constantly if you don't use something like a request counter.
Point is: you shouldn't make your users cobble those steps together, they'll get them wrong. You're in fact very likely to get them wrong yourself, if (as you say) you're still learning the ins and outs of crypto. I wish you the best of luck, but keep in mind that you have a long journey ahead of you. I'd particularly recommend you complete the Matasono crypto challenge [3] before you even think of trying your hands on raw crypto primitives.
1. http://en.wikipedia.org/wiki/Authenticated_encryption 2. http://en.wikipedia.org/wiki/Replay_attack 3. http://www.matasano.com/articles/crypto-challenges/