Oct 06.2017 - Version:
Crypter is an innovative, convenient and secure cross-platform crypto app that simplifies secure password generation and management by requiring you to only remember one bit, the MasterPass.
Crypter derives a MasterPassKey from the MasterPass obtained at setup by using the PBKDF2 key derivation algorithm (see below for the specification). It then uses PBKDF2 to derive a number of encryption keys from the MasterPassKey that can be used for the encryption of files. This method allows for the generation of very secure encryption keys for data encryption. Moreover, by publicly storing the credentials used to derive the MasterPassKey and the salts used to derive the encryption keys, you are able to produce the encryption keys at will and without needing to store them securely. Your MasterPass is the only thing that you need to remember.
Crypter never directly encrypts anything with your MasterPass. Instead, it derives a MasterPassKey from it, which it then uses to derive the encryption key used to encrypt your file. Every time a file is decrypted, the encryption key is re-derived from the MasterPassKey. Every time you set the MasterPass through the setup or reset it through Verify MasterPass, the MasterPassKey is derived from the MasterPass using a newly generated set of (random) credentials. These credentials are used to re-derive the MasterPassKey every time that Crypter is executed (i.e. the app is launched).