Qana is a Java Swing application that encrypts files, text and archives (hierarchically structured sets of files) with a 256-bit symmetric-key cipher based on established cryptographic algorithms: the scrypt password-based key-derivation function and the Fortuna cryptographically secure pseudo-random number generator, for which there is a choice of either AES-256 or Salsa20 as the underlying cipher.

Features

• It performs symmetric-key encryption with a stream cipher whose 256-bit key is derived from a passphrase. (A symmetric key means that the same key is used for encryption and decryption.)
• It maintains a database of named encryption keys, each of which is associated with a passphrase. A cryptographic hash value of a key's passphrase is stored in the database, allowing the passphrase to be verified while making recovery of the passphrase infeasible. The strength of the hash value is configurable.
• It uses well-regarded cryptographic algorithms:
  • The stream cipher that it uses for encryption and decryption is generated by a Fortuna cryptographically secure pseudo-random number generator (PRNG) from either an AES-256 block cipher running in counter mode or a Salsa20 cipher.
  • The scrypt key-derivation function is used to derive an encryption key for the cipher from a passphrase and to generate the hash values that are stored in the key database for verifying passphrases. The key-derivation function has configurable parameters that provide a trade-off between speed and key strength.
• It has an easy-to-use graphical interface, including a straightforward key-management dialog.
• The entropy sources of the Fortuna PRNG can be configured and their metrics observed to check that the generator is being supplied with entropy of a sufficient quality.

Functions

• Individual files can be encrypted.
• Text can be edited and encrypted. The encrypted text can be optionally wrapped in XML.
• A hierarchical set of files (ie, files in a directory structure) can be encrypted as an archive, which is stored as a set of encrypted files with generic names within the same directory, along with an encrypted file of metadata. Selected sets of files can be extracted or deleted from the archive, and new files added to it.
• A single file can be split into several parts whose lengths are randomly selected from a specified range. The parts are stored as a set of encrypted files with generic names. The original file can be recovered if all its parts can be found in the same directory.
• Files or text can be encrypted and concealed within an image file. The image may be chosen by the user or generated by the application.
• A file, text or an image can be generated with the same form as an encrypted output of Qana but whose apparently encrypted content is really random garbage.

Links

• Source code
• Manual  (Single HTML file)
  (JavaScript must be enabled in your browser in order to generate the manual's table of contents.)
• Screenshot of Qana

Licence

• The contents of the uk.blankaspect.qana package (including resources) may be used under the terms of version 3 of the GNU General Public License.
• All other contents of the blankaspect/qana repository may be used under the terms of the MIT License.