\documentclass[tikz,border=6pt]{standalone}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,positioning,calc}
\definecolor{ink}{HTML}{111827}
\definecolor{violet}{HTML}{7C3AED}
\definecolor{green}{HTML}{059669}
\definecolor{paper}{HTML}{FFFDF7}
\begin{document}
\begin{tikzpicture}[>=Latex, font=\small, text=ink]
  \fill[paper] (-0.5,-1.7) rectangle (8.7,1.85);
  \node[draw=ink!35, rounded corners=3pt, fill=paper, minimum width=1.15cm, minimum height=0.8cm] (b0) at (0,0) {$b$};
  \node[draw=violet!65, rounded corners=3pt, fill=violet!8, minimum width=1.15cm, minimum height=0.8cm] (b1) at (2.2,0) {$b+1$};
  \node[draw=violet!65, rounded corners=3pt, fill=violet!8, minimum width=1.15cm, minimum height=0.8cm] (b2) at (4.4,0) {$b+2$};
  \node[draw=violet!65, rounded corners=3pt, fill=violet!8, minimum width=1.15cm, minimum height=0.8cm] (b3) at (6.6,0) {$b+3$};
  \draw[->, violet, line width=0.9pt] (b0) -- node[above] {$QC$} (b1);
  \draw[->, violet, line width=0.9pt] (b1) -- node[above] {$QC$} (b2);
  \draw[->, violet, line width=0.9pt] (b2) -- node[above] {$QC$} (b3);
  \node[draw=green!65, fill=green!10, rounded corners=3pt, below=0.75cm of b1, align=center] {commit$(b)$\\ \scriptsize abuelo protegido};
  \draw[->, green!70] (b3.south) .. controls +(0,-0.9) and +(1.2,0) .. (b1.south east);
  \node[font=\footnotesize, align=center] at (3.3,1.35) {tres bloques certificados consecutivos transportan suficiente memoria};
\end{tikzpicture}
\end{document}
