If encryption is your main requirement, you could try AnyLocker - http://anylockerapp.com
It's main selling point is that it encrypts all your data (notes, pictures) with SHA-256 before storing it on your device. Give it a try (Disclosure - i am the developer in the team that published this app)
Reviews/feedback always welcome...
Nah, I already have Ben the Bodyguard[1] for that.
I don't really use it, but I use a to-do app constantly, and miss a tool to continue writing on my projects' Markdown files.
1. http://dayoneapp.com/support/passwords/
2. http://iphone.appstorm.net/reviews/lifestyle/day-one-a-gorge...
3. http://web.archive.org/web/20120902234719/http://dayoneapp.c...
The app looks really interesting, though, and I would probably have used it otherwise. Maybe now's a great time to address encryption with the focus on the Vesper app.