• Introduction
• Quick start guide
• General icons
• Accounts
• Accounts icons
• Notes
• Notes icons
• Notes menu (selection)
• Notes menu (view)
• Notes menu (edit)
• Account settings
• Security

Top Secret is a very simple application that allows you to keep basic text notes on your phone containing private information, while providing security when viewing them in a public place. Unlike password safe applications, that specialise in securing just account information, Top Secret permits any type of text data to be secured thanks to its unique freeform nature.

• Totally freeform nature; store your secrets how you want.
• Innovative viewer UI only reveals a portion of your secret text when touched; ideal for use in crowded areas.
• Client-side only; nothing is sent across a network or stored on the internet.
• All secret data encrypted using industry standard algorithms; AES 128 bit (advanced edition) or Triple DES 168 bit (standard edition).
• Password protected accounts; secure different types of data behind different passwords, using one-way AES encryption.
• Password protected backup to SD card, with encrypted data; AES 128 bit (advanced edition) or Triple DES 168 bit (standard edition).
• Password strength checker for accounts and backups; includes checking for over 500 of the most common passwords.
• Event log (advanced edition only); view recent account activity, including failed log-in attempts.
• Viewer screen auto-exit after a period of inactivity; handy if you accidentally leave the app running unattended.

In the modern digital age we often have to remember countless account passwords or entry codes for work and leisure. We may also need to keep reminders of personal information, for example dress size or inside leg measurements. The most logical place to store such information is on our phones, where it can be accessed on the go. But using portable devices in public spaces brings an increased risk of prying eyes seeing what's on the screen.

Top Secret quite simply allows you to mark lines of a given text note as sensitive. Sensitive lines are not shown automatically when the note is viewed, but may be revealed by stroking a finger below the hidden line to reveal small portions at a time. Anyone catching a glance at your screen will see, at best, just a portion of the secret text.

Before you begin using Top Secret, make sure you familiarise yourself with the differences between the standard edition (free) and advanced edition (paid).

Before you can do anything in Top Secret you need to create at least one account. Accounts protect your notes behind a password. The account creation button is at the foot of the account selection screen (the main screen when the app launches). You'll be asked to provide an account name and choose a password. Once that is done you'll be able to log in and start creating notes.

	Back: Returns to previous screen.
	Help: You're reading it!

Accounts allow multiple people to use Top Secret on the same device, without revealing their secrets to each other. On the opening screen of the application you can create a new account, or select an existing account to log in to. If only one account is set up, the application automatically jumps to the password interface.

See also: account settings.

	Create account: Create a new account. Each account must have a unique name.
	Edit account: Edit the details of an existing account. You must enter the account's password before the edit button will work.
	Delete account: Delete an existing account. For safety, you must long click (touch and hold) this button for it to register, and the current account password must be entered. A confirmation dialog will be shown, allowing you to abort. A deleted account destroys all data associated with the account.

Notes are what Top Secret is all about. They are simple text documents, with a minor difference: each note can nominate a mask character, and any line of text beginning with that character will be obscured when the note is viewed. This allows notes to hold sensitive information like usernames and passwords, without exposing it to prying eyes. Stroking the screen will reveal only a small area of the hidden text, making it readable to the user without exposing it in full to the casual glance of onlookers.

For example, in the following note the security code and the password would be obscured when viewing the note normally, assuming the note's mask character is set to #.

	Create note: Create a new note. As well as entering text, you can choose a mask character. Any line beginning with that character will be hidden when the note is viewed.
	Edit note: Edit the details of an existing note.
	Delete note: Delete an existing note. For safety, you must long click (touch and hold) this button for it to register. A confirmation dialog will be shown, allowing you to abort.

• Load (SD Card): Load a notes collection from SD Card, appending the notes to the current collection.
• Save (SD Card): Save current notes collection to SD Card.
• Settings: Account settings.
• Event log: (Advanced edition only.) Detailed log of recent activity, including failed login attempts.

Both standard and advanced editions protect the save file with a password. For extra security the data itself is also encrypted using strong industry standard algorithms; in the advanced edition AES (128 bit) is used, in the standard edition a older algorithm known as Triple DES (DESede 168 bit) is used.

• Load (SD Card): Load a notes collection from SD Card, appending the notes to the current collection.
• Save (SD Card): Save current notes collection to SD Card.

Both standard and advanced editions protect the save file with a password. For extra security the data itself is also encrypted using strong industry standard algorithms; in the advanced edition AES (128 bit) is used, in the standard edition a older algorithm known as Triple DES (DESede 168 bit) is used.

• Load (SD Card): Load text from SD Card, appending to the current text.
• Save (SD Card): Save text to SD Card.

In both the standard and advanced editions the note body is saved as plain text, without any encryption. No password is used.

The account settings screen is accessed via the menu on the note selection screen. It permits various account-specific configuration options to be set for other screens inside the application.

• Leave after inactivity: Set an inactivity timeout, after which a screen will automatically return to its parent screen. Useful should you accidentally leave the application running unattended.
• Secrets reveal circle size: Sets the size of the revealed circle area when touching the view note screen.

With an application like Top Secret security is very important. So you can make informed decisions about what to trust to Top Secret, and what not to trust, outlined below is an overview (in non-technical language) of the strengths and potential weaknesses of the application's approach to security.

Please read the following carefully.

• Editions: Top Secret comes in two variations: a free version known as the standard edition, and a paid version known as the advanced edition (available shortly after release of the stardard edition). The standard edition uses Triple DES (DESede 168 bit), a strong and widely used encryption algorithm, but the advanced edition uses its even stronger successor, AES (128 bit).
• Passwords: Top Secret is only as secure as the password you choose to protect your account. At the moment Top Secret does not demand users add digits, capital letters, or punctuation, into their passwords — it is left to the user to choose a password complexity appropriate to the importance of the data they wish to store in a given account.
• Passwords: Both standard and advanced editions of Top Secret use one-way AES encryption to secure account passwords. This makes each password considerably more secure, but means if you forget your account password, THERE IS NO WAY OF GETTING IT BACK! (See next point.)
• Backup: You should always ensure you have a backup copy of all data in case of phone loss, data corruption, or account lock out.
• Backup: A complete note, or an entire set of notes, can also be saved to a Top Secret file (.tsz). These are protected by a password using AES encryption. The standard edition encrypts the backup's note data with Triple DES (DESede 168 bit); the advanced edition uses the even stronger AES (128 bit) algorithm. Note: both editions can read each other's backup files, regardless of the encryption scheme used.
• Backup: The note editor screen lets you save just the text of a note to an external file. This data is always stored as plain text (.txt), without encryption.
• Advanced edtion: While the standard edition should be more than secure enough to hold web site account details etc., if you intend to store extremely high risk data such as bank card PIN numbers or online banking passwords, please consider upgrading to the advanced edition (when it becomes available). The advanced edition uses the AES encryption algorithm throughout, a successor to the Triple DES algorithm used in the standard edition. Although Triple DES uses a 168 bit key length, its effective strength is only considered to be 112 bits. AES uses 128 bits, and its algorithm is also faster than Triple DES.
• Advanced edition: As well as slighly stronger encryption for its note data, the advanced edition also allows access to Top Secret's event log. The event log reveals all login attempts (successful and unsuccessful), account and note creations/edits/deletions, as well as which notes have been accessed (read) and when. If you think someone has been tampering with your phone without your knowledge, the event log is a handy resource.

Disclaimer: while the application has undergone extensive testing, the developer cannot guarantee it is bug free. Therefore, any data you store using Top Secret, you do so at your own risk. The application authors are not responsible for the consequences of data loss or accidental disclosure due to using this application.