Merge branch 'master' of https://gitlab.com/kranklyboy/cryptocurrencies

Conflict on git push.

project1/a.sql

@@ -102,8 +102,8 @@ WHERE sig_id <> pk_id;
 -- #16.1.5 Get blocks with inputs that have outputs which have already been
 -- spent (double-spending)
 
--- First, get outputs that have been doubly spent
+-- First, get outputs that have more than one input
-CREATE OR REPLACE VIEW outputs_doubly_spent AS (
+CREATE OR REPLACE VIEW outputs_multiple_inputs AS (
     SELECT output_id
     FROM non_coinbase_inputs
     JOIN outputs USING(output_id)
@@ -113,14 +113,14 @@ CREATE OR REPLACE VIEW outputs_doubly_spent AS (
 -- Second, get corresponding input_id where the output was first spent
 CREATE OR REPLACE VIEW inputs_first_spent AS (
     SELECT MIN(input_id) AS input_id, output_id
-    FROM outputs_doubly_spent
+    FROM outputs_multiple_inputs
     JOIN non_coinbase_inputs USING(output_id)
     GROUP BY output_id
 );
 -- Third, combine to get invalid blocks
 INSERT INTO temporary_table
 SELECT block_id
-FROM outputs_doubly_spent
+FROM outputs_multiple_inputs
 JOIN non_coinbase_inputs USING(output_id)
 WHERE input_id NOT IN (
     SELECT input_id

project1/project1.tex

@@ -1,80 +0,0 @@
-\documentclass[12pt,a4paper]{article}
-
-\usepackage[cm]{fullpage}
-\usepackage{amsthm}
-\usepackage{amsmath}
-\usepackage{amsfonts}
-\usepackage{amssymb}
-\usepackage{xspace}
-\usepackage[english]{babel}
-\usepackage{fancyhdr}
-\usepackage{titling}
-\renewcommand{\thesection}{Exercise \Alph{section}:}
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-% This part needs customization from you %
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-% please enter your group number your names and matriculation numbers here
-%TODO
-\newcommand{\groupnumber}{04}
-\newcommand{\name}{Tobias Eidelpes, Ege Mehmet Demirsoy, Nejra Komic}
-\newcommand{\matriculation}{01527193, XXXXXXXX, XXXXXXXX, same order as the
-names}
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%           End of customization         %
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-\newcommand{\projnumber}{1}
-\newcommand{\Title}{Analysing the Blockchain}
-\setlength{\headheight}{15.2pt}
-\setlength{\headsep}{20pt}
-\setlength{\textheight}{680pt}
-\pagestyle{fancy}
-\fancyhf{} 
-\fancyhead[L]{Cryptocurrencies - Project \projnumber\ - Analysing the Blockchain}
-\fancyhead[C]{}
-\fancyhead[R]{\name}
-\renewcommand{\headrulewidth}{0.4pt}
-\fancyfoot[C]{\thepage}
-
-
-\begin{document}
-\thispagestyle{empty}
-\noindent\framebox[\linewidth]{%
- \begin{minipage}{\linewidth}%
- \hspace*{5pt} \textbf{Cryptocurrencies (WS2021/22)} \hfill Prof.~Matteo Maffei \hspace*{5pt}\\
-
- \begin{center}
-  {\bf\Large Project \projnumber~-- \Title}
- \end{center}
-
- \vspace*{5pt}\hspace*{5pt} \hfill TU Wien \hspace*{5pt}
-\end{minipage}%
-}
-\vspace{0.5cm}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-\section*{Group \groupnumber}
-Our group consists of the following members:
-\begin{center}
-\textbf{\name} %please fill the information above
-
-\matriculation %please fill the information above
-\end{center}
-
-\section{Finding invalid blocks}
-% Fill here your answers for exercise A 
-
-\section{UTXOs}
-% Fill here your answers for exercise B
-
-\section{De-anonymization}
-% Fill here your answers for exercise C
-
-\section*{Work distribution}
-%Fill in here an overview on which group member participated in which task and to which extent
-
-\end{document}
-

project1/report1.tex

@@ -0,0 +1,155 @@
+\documentclass[12pt,a4paper]{article}
+
+\usepackage[cm]{fullpage}
+\usepackage{amsthm}
+\usepackage{amsmath}
+\usepackage{amsfonts}
+\usepackage{amssymb}
+\usepackage{xspace}
+\usepackage[english]{babel}
+\usepackage{fancyhdr}
+\usepackage{titling}
+\usepackage{hyperref}
+\renewcommand{\thesection}{Exercise \Alph{section}:}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% This part needs customization from you %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% please enter your group number your names and matriculation numbers here
+%TODO
+\newcommand{\groupnumber}{04}
+\newcommand{\name}{Tobias Eidelpes, Ege Mehmet Demirsoy, Nejra Komic}
+\newcommand{\matriculation}{01527193, XXXXXXXX, XXXXXXXX, same order as the
+names}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%           End of customization         %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\newcommand{\projnumber}{1}
+\newcommand{\Title}{Analysing the Blockchain}
+\setlength{\headheight}{15.2pt}
+\setlength{\headsep}{20pt}
+\setlength{\textheight}{680pt}
+\pagestyle{fancy}
+\fancyhf{} 
+\fancyhead[L]{Cryptocurrencies - Project \projnumber\ - Analysing the Blockchain}
+\fancyhead[C]{}
+\fancyhead[R]{\name}
+\renewcommand{\headrulewidth}{0.4pt}
+\fancyfoot[C]{\thepage}
+
+
+\begin{document}
+\thispagestyle{empty}
+\noindent\framebox[\linewidth]{%
+ \begin{minipage}{\linewidth}%
+ \hspace*{5pt} \textbf{Cryptocurrencies (WS2021/22)} \hfill Prof.~Matteo Maffei \hspace*{5pt}\\
+
+ \begin{center}
+  {\bf\Large Project \projnumber~-- \Title}
+ \end{center}
+
+ \vspace*{5pt}\hspace*{5pt} \hfill TU Wien \hspace*{5pt}
+\end{minipage}%
+}
+\vspace{0.5cm}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\section*{Group \groupnumber}
+Our group consists of the following members:
+\begin{center}
+\textbf{\name} %please fill the information above
+
+\matriculation %please fill the information above
+\end{center}
+
+\section{Finding invalid blocks}
+
+For this exercise all invalid blocks contained in the database provided to us
+had to be found. While there is an
+official\footnote{\url{https://en.bitcoin.it/wiki/Protocol\_rules\#.22block.22\_messages}}
+algorithm which allows network participants to verify whether a block is invalid
+or not, the stripped-down version of the blockchain we received does not require
+all the steps. This stripped-down version of the algorithm thus specifies which
+constraints the data must satisfy:
+
+\begin{enumerate}
+    \item All blocks which do not have the coinbase transaction as their first
+        transaction are invalid. This will be achieved by creating a view which
+        lists all coinbase transactions. Then we query the database for all
+        first transactions of each block and check if that transaction is in the
+        view of all coinbase transactions. If it is not, we reject the block and
+        add it to the invalid list.
+    \item All blocks which contain transactions which do not have inputs or
+        outputs are invalid. We split this task into two queries, one for
+        checking if a block contains transactions with zero inputs and another
+        one for checking if a block contains transactions with zero outputs.
+    \item All blocks which have transactions with an invalid output value or
+        where the sum of all output values exceeds the legal money range are
+        invalid. This task is split into two queries as well. One for checking
+        if individual output values are outside of the legal money range and a
+        second one for checking if the sum of all output values per transaction
+        is outside of the legal money range.
+    \item Reject all blocks which have transactions with inputs that do not have
+        a corresponding output. For this task we first create a view which finds
+        all non coinbase transactions. The output of that query is then filtered
+        for all inputs which are not part of a coinbase transaction (so the non
+        coinbase inputs). Finally, the non coinbase inputs are joined with the
+        outputs and rows containing \texttt{NULL} as their \texttt{value}
+        indicate an invalid block.
+    \item All blocks which contain transactions where the input's
+        \texttt{sig\_id} field is not the same as the output's \texttt{pk\_id}
+        field are invalid. Since we are not interested in the coinbase
+        transactions, the query uses the non coinbase inputs again to join them
+        with the outputs. If the two fields do not match, the block is invalid.
+    \item All blocks which have inputs for which there exist outputs which have
+        already been spent are invalid. This task is split into three queries.
+        First, we find all outputs which have more than one input. Second, for
+        all the outputs found, we find the corresponding inputs where the output
+        was first spent. Third, the two tables are combined such that blocks
+        with outputs which have corresponding inputs that are not listed as the
+        first spending occurrence, are marked as invalid.
+    \item All blocks containing inputs which are not in the legal money range
+        are invalid. First, we construct a view which gathers all transactions
+        and their corresponding sum of value for all inputs. All blocks
+        containing input sums which are outside of the legal money range are
+        marked as invalid. Second, we reuse the view of all non coinbase inputs
+        and filter them for the ones which have an output value outside of the
+        legal money range.
+    \item All blocks where the sum of input values is smaller than the sum of
+        output values are invalid. This task allows us to reuse the view created
+        earlier of all input sums. Additionally, the sum of output values is
+        obtained similarly to the input sums. After joining both input sums and
+        output sums, we can filter for blocks which have smaller input sums than
+        output sums. Those blocks are invalid.
+    \item All blocks where the coinbase value is larger than the sum of the
+        block creation fee and all transaction fees are invalid. This task is
+        split into four queries. First, we create a view which shows all block
+        ids and their coinbase values. Second, we need to know the sum of all
+        input values per block. Third, we repeat that query for the sum of the
+        output values per block. Lastly, these three tables are joined and all
+        blocks which satisfy the constraint are invalid.
+\end{enumerate}
+
+Finally, the invalid blocks are written to the \texttt{invalid\_blocks} table
+and all duplicates are removed.
+
+\section{UTXOs}
+% Fill here your answers for exercise B
+
+\section{De-anonymization}
+% Fill here your answers for exercise C
+
+\section*{Work distribution}
+%Fill in here an overview on which group member participated in which task and to which extent
+
+\begin{description}
+    \item[Tobias Eidelpes] Code and report for Exercise A. 
+    \item[Ege Mehmet Demirsoy]
+    \item[Nejra Komic]
+\end{description}
+
+\end{document}
+