Safe Editor

Safe Editor is a lightweight utility specially designed for users who want to write down sensitive information that they want to protect from others who may use the computer.

Comes with a minimalistic, but clean UI

Following a quick and straightforward setup, you are welcomed by a simplistic, yet very intuitive interface that is unlikely to give you any troubles. While in the upper section, you can open as many notes as you need, the vast majority of the interface is dedicated to previewing the contents of the memos.
As you would expect from a rich text editor, the utility allows you to seamlessly add, search and edit the notes that you are creating. Although it does not seem like much, let us not forget that you can add passwords, usernames and other types of sensitive information that you are likely to modify on a regular basis.

Allows you to protect notes under a password

The highlight of the application stems from the fact that you can safeguard the contents of your notes with a solid and, preferably, hard to guess password that includes special characters. Considering that the app does not require a connection to the Internet to create the memos, there is also a lesser chance of data leaks.
At the same time, it is worth mentioning that the application integrates into Windows's context menu, so that you can easily encrypt or add a passkey to text files that you store on your local drives. Therefore, you can protect a note by specifying the password and, optionally, adding a tip, so that you can remember it next time you want to access it.
On a side note, the program also encrypts the content of the memos using two modern algorithms, namely AES and RSA.

A handy tool for creating private notes

All in all, if you are looking for an easy-to-use tool that permits you to take notes effortlessly and that enables you to safeguard the data just as easily, then perhaps Safe Editor could lend you a hand.