Commit c3fe69bb authored by mikael.beyene's avatar mikael.beyene
Browse files

Initial commit

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# Ignore Gradle project-specific cache directory
.gradle
# Ignore Gradle build output directory
build/
# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
!gradle-wrapper.jar
# Work around https://youtrack.jetbrains.com/issue/IDEA-116898
gradle/wrapper/gradle-wrapper.properties
# IntelliJ
.idea/
/*
* This file was generated by the Gradle 'init' task.
*
* This generated file contains a sample Java application project to get you started.
* For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
* User Manual available at https://docs.gradle.org/6.8.3/userguide/building_java_projects.html
*/
plugins {
// Apply the application plugin to add support for building a CLI application in Java.
application
}
repositories {
// Use JCenter for resolving dependencies.
jcenter()
}
dependencies {
implementation("info.picocli:picocli:4.6.1")
implementation("com.google.guava:guava:29.0-jre")
// Use JUnit test framework
testImplementation("junit:junit:4.13")
}
application {
// Define the main class for the application.
//mainClass.set("edu.kit.aifb.cii.pow.App")
}
tasks.withType<Jar>() {
manifest {
attributes["Main-Class"] = "edu.kit.aifb.cii.pow.App"
}
configurations["compileClasspath"].forEach { file: File ->
from(zipTree(file.absoluteFile))
}
}
java {
toolchain {
languageVersion.set(JavaLanguageVersion.of(12))
}
}
\ No newline at end of file
#!/usr/bin/env sh
#
# Copyright 2015 the original author or authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
##############################################################################
##
## Gradle start up script for UN*X
##
##############################################################################
# Attempt to set APP_HOME
# Resolve links: $0 may be a link
PRG="$0"
# Need this for relative symlinks.
while [ -h "$PRG" ] ; do
ls=`ls -ld "$PRG"`
link=`expr "$ls" : '.*-> \(.*\)$'`
if expr "$link" : '/.*' > /dev/null; then
PRG="$link"
else
PRG=`dirname "$PRG"`"/$link"
fi
done
SAVED="`pwd`"
cd "`dirname \"$PRG\"`/" >/dev/null
APP_HOME="`pwd -P`"
cd "$SAVED" >/dev/null
APP_NAME="Gradle"
APP_BASE_NAME=`basename "$0"`
# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
# Use the maximum available, or set MAX_FD != -1 to use that value.
MAX_FD="maximum"
warn () {
echo "$*"
}
die () {
echo
echo "$*"
echo
exit 1
}
# OS specific support (must be 'true' or 'false').
cygwin=false
msys=false
darwin=false
nonstop=false
case "`uname`" in
CYGWIN* )
cygwin=true
;;
Darwin* )
darwin=true
;;
MINGW* )
msys=true
;;
NONSTOP* )
nonstop=true
;;
esac
CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
# Determine the Java command to use to start the JVM.
if [ -n "$JAVA_HOME" ] ; then
if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
# IBM's JDK on AIX uses strange locations for the executables
JAVACMD="$JAVA_HOME/jre/sh/java"
else
JAVACMD="$JAVA_HOME/bin/java"
fi
if [ ! -x "$JAVACMD" ] ; then
die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
fi
else
JAVACMD="java"
which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
fi
# Increase the maximum file descriptors if we can.
if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
MAX_FD_LIMIT=`ulimit -H -n`
if [ $? -eq 0 ] ; then
if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
MAX_FD="$MAX_FD_LIMIT"
fi
ulimit -n $MAX_FD
if [ $? -ne 0 ] ; then
warn "Could not set maximum file descriptor limit: $MAX_FD"
fi
else
warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
fi
fi
# For Darwin, add options to specify how the application appears in the dock
if $darwin; then
GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
fi
# For Cygwin or MSYS, switch paths to Windows format before running java
if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
APP_HOME=`cygpath --path --mixed "$APP_HOME"`
CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
JAVACMD=`cygpath --unix "$JAVACMD"`
# We build the pattern for arguments to be converted via cygpath
ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
SEP=""
for dir in $ROOTDIRSRAW ; do
ROOTDIRS="$ROOTDIRS$SEP$dir"
SEP="|"
done
OURCYGPATTERN="(^($ROOTDIRS))"
# Add a user-defined pattern to the cygpath arguments
if [ "$GRADLE_CYGPATTERN" != "" ] ; then
OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
fi
# Now convert the arguments - kludge to limit ourselves to /bin/sh
i=0
for arg in "$@" ; do
CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
CHECK2=`echo "$arg"|egrep -c "^-"` ### Determine if an option
if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then ### Added a condition
eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
else
eval `echo args$i`="\"$arg\""
fi
i=`expr $i + 1`
done
case $i in
0) set -- ;;
1) set -- "$args0" ;;
2) set -- "$args0" "$args1" ;;
3) set -- "$args0" "$args1" "$args2" ;;
4) set -- "$args0" "$args1" "$args2" "$args3" ;;
5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
esac
fi
# Escape application args
save () {
for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
echo " "
}
APP_ARGS=`save "$@"`
# Collect all arguments for the java command, following the shell quoting and substitution rules
eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
exec "$JAVACMD" "$@"
@rem
@rem Copyright 2015 the original author or authors.
@rem
@rem Licensed under the Apache License, Version 2.0 (the "License");
@rem you may not use this file except in compliance with the License.
@rem You may obtain a copy of the License at
@rem
@rem https://www.apache.org/licenses/LICENSE-2.0
@rem
@rem Unless required by applicable law or agreed to in writing, software
@rem distributed under the License is distributed on an "AS IS" BASIS,
@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@rem See the License for the specific language governing permissions and
@rem limitations under the License.
@rem
@if "%DEBUG%" == "" @echo off
@rem ##########################################################################
@rem
@rem Gradle startup script for Windows
@rem
@rem ##########################################################################
@rem Set local scope for the variables with windows NT shell
if "%OS%"=="Windows_NT" setlocal
set DIRNAME=%~dp0
if "%DIRNAME%" == "" set DIRNAME=.
set APP_BASE_NAME=%~n0
set APP_HOME=%DIRNAME%
@rem Resolve any "." and ".." in APP_HOME to make it shorter.
for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
@rem Find java.exe
if defined JAVA_HOME goto findJavaFromJavaHome
set JAVA_EXE=java.exe
%JAVA_EXE% -version >NUL 2>&1
if "%ERRORLEVEL%" == "0" goto execute
echo.
echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
echo.
echo Please set the JAVA_HOME variable in your environment to match the
echo location of your Java installation.
goto fail
:findJavaFromJavaHome
set JAVA_HOME=%JAVA_HOME:"=%
set JAVA_EXE=%JAVA_HOME%/bin/java.exe
if exist "%JAVA_EXE%" goto execute
echo.
echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
echo.
echo Please set the JAVA_HOME variable in your environment to match the
echo location of your Java installation.
goto fail
:execute
@rem Setup the command line
set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
@rem Execute Gradle
"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
:end
@rem End local scope for the variables with windows NT shell
if "%ERRORLEVEL%"=="0" goto mainEnd
:fail
rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
rem the _cmd.exe /c_ return code!
if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
exit /b 1
:mainEnd
if "%OS%"=="Windows_NT" endlocal
:omega
/*
* This file was generated by the Gradle 'init' task.
*
* The settings file is used to specify which projects to include in your build.
*
* Detailed information about configuring a multi-project build in Gradle can be found
* in the user manual at https://docs.gradle.org/6.8.3/userguide/multi_project_builds.html
*/
rootProject.name = "proof-of-work"
package edu.kit.aifb.cii.pow;
import picocli.CommandLine;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.NumberFormat;
import java.time.Instant;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.TreeMap;
// https://www.baeldung.com/sha-256-hashing-java
// https://en.bitcoin.it/wiki/Protocol_documentation
// https://en.bitcoin.it/wiki/Block_hashing_algorithm
// https://www.baeldung.com/java-blockchain
public class App {
public static void main(String[] args) throws NoSuchAlgorithmException {
Options options = parseArguments(args);
if (options == null) return;
// Try different targets. The maximum target is Integer.MAX (i.e., 2^32 -1)
int target = (int) (Integer.MAX_VALUE * options.difficultyPercentage);
// this is the first block
Block genesis = new Block.Builder()
.setVersion(1)
.setPreviousHash("")
.setHash("0xDEADBEEF") // this hash is just an example value...
.setMerkleRoot("")
.setTimeStamp(Instant.now().toEpochMilli())
.setTarget(target)
.setNonce(1337)
.build();
// This is NOT a real Merkle tree
Map<String, Object> merkleTree = new TreeMap<>();
// Add some random fake transactions to our fake Merkle tree
merkleTree.put("1", "TRANSACTION" + new Random().nextInt());
merkleTree.put("2", "TRANSACTION" + new Random().nextInt());
// Here we set up everything for the next block
Block.Builder blockBuilder = new Block.Builder()
.setVersion(1)
.setPreviousHash(genesis.getHash())
// Normally, we would need the Merkle tree root...
.setMerkleRoot(String.format("0x%08X", merkleTree.hashCode()))
.setTarget(target);
// We'll use SHA-256 for hashing just like Bitcoin
MessageDigest md = MessageDigest.getInstance("SHA-256");
boolean foundBlock = false;
int nonce = 1;
// We'll update our nonce until we compute a hash that is below the target
while (!foundBlock) {
// We use milliseconds, instead of seconds to get more variability in the resulting hash
blockBuilder
.setTimeStamp(Instant.now().toEpochMilli())
.setNonce(nonce);
// Here we compute the SHA-256 hash. The result consists of eight 32-bit words (in total 256 bit)
byte[] sha256Hash = md.digest(blockBuilder.getData().getBytes());
// For the purpose of this example, we hash again to get a single, 32-bit integer
int hash = Math.abs(new BigInteger(sha256Hash).hashCode());
blockBuilder.setHash(String.format("0x%08X", hash));
//System.out.println("Hash =" + String.format("0x%08X", hash) + ", " + hash);
//System.out.println("Target=" + String.format("0x%08X", target) + ", " + target);
// if hash is smaller than target, we found a nonce
// if the target is big, it's pretty easy to find a nonce, that leads to a hash which is below the target
if (hash < target) {
foundBlock = true;
} else {
// if not, we need to try again with another nonce
nonce++;
}
// we stop after a number of tries, since this is only an exercise
if (nonce > 1_000_000)
break;
}
System.out.println("Found block=" + foundBlock);
System.out.println("Number of tries=" + NumberFormat.getInstance().format(nonce));
if (foundBlock) {
Block block = blockBuilder.build();
System.out.println("Hash =" + block.getHash());
System.out.println("Target=" + String.format("0x%08X", target));
System.out.println(block);
}
}
private static Options parseArguments(String[] args) {
Options options = new Options();
CommandLine cmd = new CommandLine(options);
cmd.setUsageHelpWidth(120);
try {
List<CommandLine> parsed = cmd.parse(args);
if (parsed.size() != 1) {
System.err.println("Number of arguments not supported!");
cmd.usage(System.out);
return null;
} else if (cmd.isUsageHelpRequested()) {
cmd.usage(System.out);
return null;
} else if (cmd.isVersionHelpRequested()) {
cmd.printVersionHelp(System.out);
return null;
}
} catch (CommandLine.ParameterException ex) {
System.err.println(ex.getMessage());
if (!CommandLine.UnmatchedArgumentException.printSuggestions(ex, System.err)) {
ex.getCommandLine().usage(System.err);
}
return null;
}
return options;
}
}
package edu.kit.aifb.cii.pow;
import com.google.common.base.MoreObjects;
/**
* See: https://en.bitcoin.it/wiki/Block_hashing_algorithm
*/
public final class Block {
// Block version information
private final int version;
// The hash value of the previous block this particular block references
private final String previousHash;
// The hash value of the current block
// Should not be saved, since it can be computed when needed
private final String hash;
// The reference to a Merkle tree collection which is a hash of all transactions related to this block
private final String merkleRoot;
// A timestamp recording when this block was created (will overflow in 2106[2])
// Using long instead of int here
private final long timeStamp;
// The calculated difficulty target being used for this block
// Bitcoins represents the target as in the 'bits' format
// see: https://learnmeabitcoin.com/technical/bits
private final int target;
// The nonce used to generate this block; to allow variations of the header and compute different hashes
private final int nonce;
/*
* 4 version int32_t Block version information (note, this is signed)
* 32 prev_block char[32] The hash value of the previous block this particular block references
* 32 merkle_root char[32] The reference to a Merkle tree collection which is a hash of all transactions related to this block
* 4 timestamp uint32_t A timestamp recording when this block was created (Will overflow in 2106[2])
* 4 bits uint32_t The calculated difficulty target being used for this block
* 4 nonce uint32_t The nonce used to generate this block… to allow variations of the header and compute different hashes
*/
public Block(Builder builder) {
this.version = builder.version;
this.previousHash = builder.previousHash;
this.hash = builder.hash;
this.merkleRoot = builder.merkleRoot;
this.timeStamp = builder.timeStamp;
this.target = builder.target;
this.nonce = builder.nonce;
}
public int getVersion() {
return version;
}
public String getPreviousHash() {
return previousHash;
}
public String getHash() {
return hash;
}
public String getMerkleRoot() {
return merkleRoot;
}
public long getTimeStamp() {
return timeStamp;
}
public int getTarget() {
return target;
}
public int getNonce() {
return nonce;
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("version", version)
.add("previousHash", previousHash)
.add("hash", hash)
.add("merkleRoot", merkleRoot)
.add("timeStamp", timeStamp)
.add("target", target)
.add("nonce", nonce)
.toString();
}
public static class Builder {
private int version;
private String previousHash;
private String hash;
private String merkleRoot;
private long timeStamp;
private int target;
private int nonce;
public Builder setVersion(int version) {
this.version = version;
return this;
}
public Builder setPreviousHash(String previousHash) {
this.previousHash = previousHash;
return this;
}
public Builder setHash(String hash) {
this.hash = hash;
return this;
}
public Builder setMerkleRoot(String merkleRoot) {
this.merkleRoot = merkleRoot;
return this;
}
public Builder setTimeStamp(long timeStamp) {
this.timeStamp = timeStamp;
return this;
}
public Builder setTarget(int target) {
this.target = target;
return this;
}
public Builder setNonce(int nonce) {
this.nonce = nonce;
return this;
}
public String getData() {