Description

Winner of the Yubico Monthly Developercompetition March 2013: http://forum.yubico.com/viewtopic.php?f=25&t=1023

Want to store your notes fully encrypted? Don't feel likesharing the notes with the entire internet? Look no further!

YubiNotes is a different note app. Its secure and the notes aretruly for your eyes only. YubiNotes is a open source secure notesapp for Android that supports using either a password or theYubiKey NEO to encrypt/decrypt notes. Encryption/Decryption isbased on a simple lock system that stores and wipes necessary keysfor decryption.

YubiNotes is the perfect companion for anyone with a YubiKey NEOor the desire to keep their secrets to themselves.

Notes are encrypted using AES/CBC with PKCS5 Padding.Theencryption and decryption process is based on 4 security keys. Thefirst two are generated the first time the app is started andsubsequently stored for safe keeping. The second two are the resultof the hashed password or Yubikey input string.

As long as the device is locked only the unique device id keysare stored on the device. The other two keys are wiped when thenote store is locked. A one-way hash of the password is also storedon the device when password mode is used.

When decrypting the notes, the following will happen in PasswordMode:

The password provided from the user is hashed and checkedagainst the stored hash value. If it matches, the hashed passwordis separated into two hash strings which are then XOR'ed with thefirst and second security key. The resulting values are then usedas IV and key and used for decrypting the notes.

When decrypting notes in YubiKey mode, the procedure issimilar.

The string provided by the YubiKey is XOR'ed first with thefirst key, and then with the second. The resulting two values areused as IV and key and used for decrypting the notes.