Secrets for Android is an application to securely store and manage passwords and secrets on your Android phone. It uses techniques like strong encryption and auto-logout to help ensure that your secrets remain safe (assuming you use a good master password!). Context-sensitive tips guide you along through its operation, making it easy to use.
Secrets for Android is open source using the Apache 2.0 licence, so you can examine the code yourself, or modify it to your needs.