/**
   * @defgroup pkg_tweetnacl TweetNaCl high-security cryptographic library
   * @ingroup  pkg
   * @ingroup  sys
   * @brief    Provides the TweetNaCl high-security cryptographic library.
   *
   * # TweetNaCl RIOT package
   *
   * TweetNaCl is the world's first auditable high-security cryptographic library.
   * TweetNaCl fits into just 100 tweets while supporting all 25 of the C NaCl
   * functions used by applications. TweetNaCl is a self-contained public-domain C
   * library, so it can easily be integrated into applications.
   * 
   * NaCl (pronounced "salt") is a new easy-to-use high-speed software library for
   * network communication, encryption, decryption, signatures, etc. NaCl's goal is
   * to provide all of the core operations needed to build higher-level
   * cryptographic tools.
   * 
   * Of course, other libraries already exist for these core operations. NaCl
   * advances the state of the art by improving security, by improving usability,
   * and by improving speed.
   * 
   * (from https://nacl.cr.yp.to/ and http://tweetnacl.cr.yp.to/)
   * 
   * You can find the API and more information [here](https://nacl.cr.yp.to/), since
   * the sources are not documented due to the aim for fitting in 100 tweets.
   * 
   * ## Requirements
   *
   * TweetNaCl requires more than 2K of stack, so beware that you're allocating at
   * least `THREAD_STACKSIZE_DEFAULT + 2048` bytes.
   * 
   * You can do it easily by adding:
   * 
   * ```makefile
   * CFLAGS += '-DTHREAD_STACKSIZE_MAIN=(THREAD_STACKSIZE_DEFAULT + 2048)'
   * ```
   * 
   * to your makefile.
   * 
   * ## Usage
   *
   * Just add it as a package in your application:
   * 
   * ```makefile
   * USEPKG += tweetnacl
   * ```
   * 
   * And don't forget to include the header:
   * 
   * ```c
   * #include <tweetnacl.h>
   * ```
   *
   * @see     https://tweetnacl.cr.yp.to/
   */