Package pgfkeys Error: I do not know the key '/tikz/box' and I am going to ignore it

Question

When I am compiling this code using xelatex 2018:

\begin{tikzpicture}[sibling distance=80pt] 
   \node[box] {TeX}
   child {node[box] {Plain\TeX}} child {node[box] {\LaTeX}
   child {node[box] {amsmath}} child {node[box] {graphicx}} child {node[box] {hyperref}}
}; \end{tikzpicture}

Throw this error:

Package pgfkeys Error: I do not know the key '/tikz/box' and I am going to ignore it. Perhaps you misspelled it. ...icture}[sibling distance=80pt] \node[box]

this is my reference:

\usepackage{pgf}
\usepackage{tikz} % Required for drawing custom shapes
\usetikzlibrary{shapes,arrows,automata}

What package missing?

Answer 1

box is not a predefined style so you may want to define it in your code. One possible definition could be

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{automata}
\begin{document}
\begin{tikzpicture}[sibling distance=80pt,box/.style={rectangle,draw}] 
   \node[box] {TeX}
   child {node[box] {Plain\TeX}} child {node[box] {\LaTeX}
   child {node[box] {amsmath}} child {node[box] {graphicx}} child {node[box] {hyperref}}
}; \end{tikzpicture}
\end{document}

Answer 2

I am also facing error

Extra }, or forgotten \endgroup. }

Kindly guide, what is missing in it. I have copied the code from below URL, and only modify the box items How to draw a figure of taxonomy in tikz or similars

\documentclass[border=10pt]{standalone}
\usepackage[edges]{forest}
\usetikzlibrary{shadows.blur}
\begin{document}
% addaswyd o ateb marmot: https://tex.stackexchange.com/a/436172/
% starting point: https://tex.stackexchange.com/a/341454/121799
\begin{forest}
  forked edges,
  for tree={font=\sffamily, rounded corners, top color=gray!5, bottom color=gray!10, edge+={darkgray, line width=1pt}, draw=darkgray, align=center, anchor=children},
  before packing={where n children=3{calign child=2, calign=child edge}{}},
  before typesetting nodes={where content={}{coordinate}{}},
  where level<=1{line width=2pt}{line width=1pt},
  [SDA, blur shadow
    [Symetric
      [310131432]
    ]
    [Asymetric
     [Homomorphic
        [Fog-Based
            [PHE
                [61 79 80]
            ]
        ]
        [Non-Fog-Based
            [PHE
                [Paillier
                    [6,11,23,30,31,34,37,39,40,44,53,54,56,69,70,72,73,74,75,76]
                ]
                [Elgamal
                    [4,5,38,71]
                ]
            ]
            [SWHE
                [7,84]
            ]
            [FHE Schemes
                [57,58,71]
            ]       
        ]
     
     ]
     [Non Homomorphic
        [No-Fog-Based
            [SMPC
                    [678283]
            ]   
            [Others
                [89212645]
            ]
        ]   
        [Fog-Based
            [62]
        ]
     ]
    ]
  ]
\end{forest}
\end{document}