Strong passphrase experiment app for iPhone and iPad
Developer: WIlliam Cheswick
First release : 12 May 2014
App size: 1.66 Mb
This is an experimental app to see if there is a way for users to remember pass phrases that correspond to long, computer-generated random keys. The random keys generated go up to 105 bits long (hence, the name.) Random keys are generated by /dev/random, though the next version will include additional entropy from the video camera, a la the lava lamp generation from many years ago.
The keys are encoded using one of many non-secret dictionaries, and the user is expected to eventually learn a phrase of pets seven random words.
These keys are used to lock a simple memo-pad type file with AES256 encryption and PBKDF key derivation techniques. The encoded envelope is saved as a UTF-8 text file (extension .105) that can be stored, mailed, and installed.
Note that this app does not envision storage of any keys permanently on a computer, but the keychain may be used until the passphrase is learned.