A LaTeX package for generating UUID Version 4

uuid.sty

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{uuid}[2019/04/30 v0.1]

\newif\ifuuid@lowercase
\uuid@lowercasefalse

\DeclareOption{lowercase}{\uuid@lowercasetrue}

\ProcessOptions\relax

\ifdefined\pdfuniformdeviate
  \let\uuid@uniformdeviate\pdfuniformdeviate
\else\ifdefined\uniformdeviate
  \let\uuid@uniformdeviate\uniformdeviate
\else
  \PackageError{uuid}{\detokenize{This LaTeX engine does not support \pdfuniformdeviate or \uniformdeviate}}\@ehc
\fi\fi

\def\uuid@randomdigit@upper{\ifcase\uuid@uniformdeviate16\space\space0\or1\or2\or3\or4\or5\or6\or7\or8\or9\or A\or B\or C\or D\or E\else F\fi}
\def\uuid@variantdigit@upper{\ifcase\uuid@uniformdeviate4\space\space8\or9\or A\or B\fi}

\def\uuid@randomdigit@lower{\ifcase\uuid@uniformdeviate16\space\space0\or1\or2\or3\or4\or5\or6\or7\or8\or9\or a\or b\or c\or d\or e\else f\fi}
\def\uuid@variantdigit@lower{\ifcase\uuid@uniformdeviate4\space\space8\or9\or a\or b\fi}

\def\uuid@randomdigit{\ifuuid@lowercase\uuid@randomdigit@lower\else\uuid@randomdigit@upper\fi}
\def\uuid@variantdigit{\ifuuid@lowercase\uuid@variantdigit@lower\else\uuid@variantdigit@upper\fi}

\newcommand*\UUID{%
  \uuid@randomdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit
  \uuid@randomdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit-%
  \uuid@randomdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit-%
  4\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit-%
  \uuid@variantdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit-%
  \uuid@randomdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit
  \uuid@randomdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit
  \uuid@randomdigit\uuid@randomdigit\uuid@randomdigit\uuid@randomdigit
}

\endinput