Blockchain!

2021-11-21 20:35:10 -05:00 · 2021-11-21 20:35:10 -05:00 · 763c968a72
commit 763c968a72
20 changed files with 1015 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,154 @@
+# ---> Gradle
+.gradle
+build/
+!src/**/build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+bin/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# ---> Java
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+# ---> JetBrains
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# AWS User-specific
+.idea/**/aws.xml
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+# ---> Windows
+# Windows thumbnail cache files
+Thumbs.db
+Thumbs.db:encryptable
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
--- a/.idea/.gitignore
+++ b/.idea/.gitignore
@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <bytecodeTargetLevel target="11" />
+  </component>
+</project>
--- a/.idea/jarRepositories.xml
+++ b/.idea/jarRepositories.xml
@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="MavenRepo" />
+      <option name="name" value="MavenRepo" />
+      <option name="url" value="https://repo.maven.apache.org/maven2/" />
+    </remote-repository>
+  </component>
+</project>
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="FrameworkDetectionExcludesConfiguration">
+    <file type="web" url="file://$PROJECT_DIR$" />
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" project-jdk-name="openjdk-17" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
--- a/.idea/runConfigurations.xml
+++ b/.idea/runConfigurations.xml
@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RunConfigurationProducerService">
+    <option name="ignoredProducers">
+      <set>
+        <option value="com.android.tools.idea.compose.preview.runconfiguration.ComposePreviewRunConfigurationProducer" />
+      </set>
+    </option>
+  </component>
+</project>
--- a/.idea/vcs.xml
+++ b/.idea/vcs.xml
@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
--- a/README.md
+++ b/README.md
@ -0,0 +1,3 @@
+# NevCoin
+
+Personal Blockchain!
--- a/build.gradle
+++ b/build.gradle
@ -0,0 +1,18 @@
+plugins {
+    id 'java'
+    id 'org.springframework.boot' version '2.6.0'
+    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
+}
+
+group 'tech.nevets'
+version '1.0'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'com.google.code.gson:gson:2.8.9'
+    implementation group: 'org.bouncycastle', name: 'bcprov-jdk15on', version: '1.52'
+    implementation 'org.springframework.boot:spring-boot-starter'
+}
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
--- a/185
+++ b/185
@ -0,0 +1,185 @@
+#!/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 "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MSYS* | MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$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 "$JAVACMD" "$@"
--- a/gradlew.bat
+++ b/gradlew.bat
@ -0,0 +1,89 @@
+@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
--- a/settings.gradle
+++ b/settings.gradle
@ -0,0 +1,2 @@
+rootProject.name = 'NevCoin'
+
--- a/src/main/java/tech/nevets/nevcoin/Block.java
+++ b/src/main/java/tech/nevets/nevcoin/Block.java
@ -0,0 +1,61 @@
+package tech.nevets.nevcoin;
+
+import tech.nevets.nevcoin.transactions.Transaction;
+import tech.nevets.nevcoin.util.StringUtil;
+
+import java.util.ArrayList;
+import java.util.Date;
+
+public class Block {
+
+    public String hash;
+    public String previousHash;
+    public String merkleRoot;
+    public ArrayList<Transaction> transactions = new ArrayList<Transaction>();
+    //private String data;
+    private long timeStamp;
+    private int nonce;
+
+    public Block(String previousHash) {
+        //this.data = data;
+        this.previousHash = previousHash;
+        this.timeStamp = new Date().getTime();
+        this.hash = calculateHash();
+    }
+
+    public String calculateHash() {
+        String calculatedHash = StringUtil.applySha256(
+                previousHash
+                + Long.toString(timeStamp)
+                + Integer.toString(nonce)
+                + merkleRoot
+                //+ data
+                );
+        return calculatedHash;
+    }
+
+    public void mineBlock(int difficulty) {
+        merkleRoot = StringUtil.getMerkleRoot(transactions);
+        String target = StringUtil.getDifficultyString(difficulty);
+
+        while (!hash.substring(0, difficulty).equals(target)) {
+            nonce ++;
+            hash = calculateHash();
+        }
+        System.out.println("Block mined: " + hash);
+    }
+
+    public boolean addTransaction(Transaction transaction) {
+        if (transaction == null) return false;
+        if (!"0".equals(previousHash)) {
+            if (transaction.processTransaction() != true) {
+                System.out.println("Transaction failed to process. Discarded.");
+                return false;
+            }
+        }
+
+        transactions.add(transaction);
+        System.out.println("Transaction Successfully added to Block");
+        return true;
+    }
+}
--- a/src/main/java/tech/nevets/nevcoin/NevCoin.java
+++ b/src/main/java/tech/nevets/nevcoin/NevCoin.java
@ -0,0 +1,143 @@
+package tech.nevets.nevcoin;
+
+import tech.nevets.nevcoin.transactions.Transaction;
+import tech.nevets.nevcoin.transactions.TransactionInput;
+import tech.nevets.nevcoin.transactions.TransactionOutput;
+
+import java.security.Security;
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class NevCoin {
+
+    public static ArrayList<Block> blockChain = new ArrayList<Block>();
+    public static HashMap<String, TransactionOutput> UTXOs = new HashMap<String, TransactionOutput>();
+
+    public static int difficulty = 10;
+    public static float minimumTransaction = 0.1f;
+    public static Wallet walletA;
+    public static Wallet walletB;
+    public static Transaction genesisTransaction;
+
+    public static void main(String[] args) {
+
+        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
+
+        walletA = new Wallet();
+        walletB = new Wallet();
+        Wallet coinbase = new Wallet();
+
+        genesisTransaction = new Transaction(coinbase.publicKey, walletA.publicKey, 100f, null);
+        genesisTransaction.generateSignature(coinbase.privateKey);
+        genesisTransaction.transactionId = "0";
+        genesisTransaction.outputs.add(new TransactionOutput(genesisTransaction.recipient, genesisTransaction.value, genesisTransaction.transactionId));
+        UTXOs.put(genesisTransaction.outputs.get(0).id, genesisTransaction.outputs.get(0));
+
+        System.out.println("Creating and Mining Genesis block... ");
+        Block genesis = new Block("0");
+        genesis.addTransaction(genesisTransaction);
+        addBlock(genesis);
+
+        Block block1 = new Block(genesis.hash);
+        System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+        System.out.println("\nWalletA is Attempting to send funds (40) to WalletB...");
+        block1.addTransaction(walletA.sendFunds(walletB.publicKey, 40f));
+        addBlock(block1);
+        System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+        System.out.println("WalletB's balance is: " + walletB.getBalance());
+
+        Block block2 = new Block(block1.hash);
+        System.out.println("\nWalletA Attempting to send more funds (1000) than it has...");
+        block2.addTransaction(walletA.sendFunds(walletB.publicKey, 1000f));
+        addBlock(block2);
+        System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+        System.out.println("WalletB's balance is: " + walletB.getBalance());
+
+        Block block3 = new Block(block2.hash);
+        System.out.println("\nWalletB is Attempting to send funds (20) to WalletA...");
+        block3.addTransaction(walletB.sendFunds( walletA.publicKey, 20));
+        System.out.println("\nWalletA's balance is: " + walletA.getBalance());
+        System.out.println("WalletB's balance is: " + walletB.getBalance());
+
+        isChainValid();
+
+    }
+
+    public static Boolean isChainValid() {
+        Block currentBlock;
+        Block previousBlock;
+        String hashTarget = new String(new char[difficulty]).replace('\0', '0');
+        HashMap<String,TransactionOutput> tempUTXOs = new HashMap<String,TransactionOutput>();
+        tempUTXOs.put(genesisTransaction.outputs.get(0).id, genesisTransaction.outputs.get(0));
+
+        for (int i = 1; i < blockChain.size(); i++) {
+
+            currentBlock = blockChain.get(i);
+            previousBlock = blockChain.get(i - 1);
+
+            if (!currentBlock.hash.equals(currentBlock.calculateHash())) {
+                System.out.println("Current Hashes not equal");
+                return false;
+            }
+
+            if (!previousBlock.hash.equals(currentBlock.previousHash)) {
+                System.out.println("Previous Hashes not equal");
+                return false;
+            }
+
+            if (!currentBlock.hash.substring(0, difficulty).equals(hashTarget)) {
+                System.out.println("This block hasn't been mined");
+                return false;
+            }
+
+            TransactionOutput tempOutput;
+            for (int t = 0; t < currentBlock.transactions.size(); t++) {
+                Transaction currentTransaction = currentBlock.transactions.get(t);
+
+                if (!currentTransaction.verifySignature()) {
+                    System.out.println("#Signature on Transaction(" + t + ") is Invalid");
+                    return false;
+                }
+                if (currentTransaction.getInputsValue() != currentTransaction.getOutputsValue()) {
+                    System.out.println("#Inputs are note equal to outputs on Transaction(" + t + ")");
+                    return false;
+                }
+
+                for (TransactionInput input: currentTransaction.inputs) {
+                    tempOutput = tempUTXOs.get(input.transactionOutputId);
+
+                    if (tempOutput == null) {
+                        System.out.println("#Referenced input on Transaction(" + t + ") is Missing");
+                        return false;
+                    }
+
+                    if (input.UTXO.value != tempOutput.value) {
+                        System.out.println("#Referenced input Transaction(" + t + ") value is Invalid");
+                        return false;
+                    }
+
+                    tempUTXOs.remove(input.transactionOutputId);
+                }
+
+                for (TransactionOutput output: currentTransaction.outputs) {
+                    tempUTXOs.put(output.id, output);
+                }
+
+                if (currentTransaction.outputs.get(0).recipient != currentTransaction.recipient) {
+                    System.out.println("#Transaction(" + t + ") output recipient is not who it should be");
+                    return false;
+                }
+                if (currentTransaction.outputs.get(1).recipient != currentTransaction.sender) {
+                    System.out.println("#Transaction(" + t + ") output 'change' is not sender.");
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    public static void addBlock(Block newBlock) {
+        newBlock.mineBlock(difficulty);
+        blockChain.add(newBlock);
+    }
+}
--- a/src/main/java/tech/nevets/nevcoin/Wallet.java
+++ b/src/main/java/tech/nevets/nevcoin/Wallet.java
@ -0,0 +1,75 @@
+package tech.nevets.nevcoin;
+
+import tech.nevets.nevcoin.transactions.Transaction;
+import tech.nevets.nevcoin.transactions.TransactionInput;
+import tech.nevets.nevcoin.transactions.TransactionOutput;
+
+import java.security.*;
+import java.security.spec.ECGenParameterSpec;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
+public class Wallet {
+    public PrivateKey privateKey;
+    public PublicKey publicKey;
+
+    public HashMap<String, TransactionOutput> UTXOs = new HashMap<String, TransactionOutput>();
+
+    public Wallet() {
+        generateKeyPair();
+    }
+
+    public void generateKeyPair() {
+        try {
+            KeyPairGenerator keyGen = KeyPairGenerator.getInstance("ECDSA", "BC");
+            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
+            ECGenParameterSpec ecSpec = new ECGenParameterSpec("prime192v1");
+
+            keyGen.initialize(ecSpec, random);
+            KeyPair keyPair = keyGen.generateKeyPair();
+
+            privateKey = keyPair.getPrivate();
+            publicKey = keyPair.getPublic();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public float getBalance() {
+        float total = 0;
+        for (Map.Entry<String, TransactionOutput> item: NevCoin.UTXOs.entrySet()) {
+            TransactionOutput UTXO = item.getValue();
+            if (UTXO.isMine(publicKey)) {
+                UTXOs.put(UTXO.id, UTXO);
+                total += UTXO.value ;
+            }
+        }
+        return total;
+    }
+
+    public Transaction sendFunds(PublicKey _recipient, float value ) {
+        if(getBalance() < value) {
+            System.out.println("#Not Enough funds to send transaction. Transaction Discarded.");
+            return null;
+        }
+        ArrayList<TransactionInput> inputs = new ArrayList<TransactionInput>();
+
+        float total = 0;
+        for (Map.Entry<String, TransactionOutput> item: UTXOs.entrySet()) {
+            TransactionOutput UTXO = item.getValue();
+            total += UTXO.value;
+            inputs.add(new TransactionInput(UTXO.id));
+            if (total > value) break;
+        }
+
+        Transaction newTransaction = new Transaction(publicKey, _recipient, value, inputs);
+        newTransaction.generateSignature(privateKey);
+
+        for (TransactionInput input: inputs) {
+            UTXOs.remove(input.transactionOutputId);
+        }
+
+        return newTransaction;
+    }
+}
--- a/src/main/java/tech/nevets/nevcoin/transactions/Transaction.java
+++ b/src/main/java/tech/nevets/nevcoin/transactions/Transaction.java
@ -0,0 +1,95 @@
+package tech.nevets.nevcoin.transactions;
+
+import tech.nevets.nevcoin.NevCoin;
+import tech.nevets.nevcoin.util.StringUtil;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.util.ArrayList;
+
+public class Transaction {
+    public String transactionId;
+    public PublicKey sender;
+    public PublicKey recipient;
+    public float value;
+    public byte[] signature;
+
+    public ArrayList<TransactionInput> inputs = new ArrayList<TransactionInput>();
+    public ArrayList<TransactionOutput> outputs = new ArrayList<TransactionOutput>();
+
+    private static int sequence = 0;
+
+    public Transaction(PublicKey from, PublicKey to, float value, ArrayList<TransactionInput> inputs) {
+        this.sender = from;
+        this.recipient = to;
+        this.value = value;
+        this.inputs = inputs;
+    }
+
+    public boolean processTransaction() {
+        if (verifySignature() == false) {
+            System.out.println("#Transaction Signature failed to verify");
+            return false;
+        }
+
+        for (TransactionInput i : inputs) {
+            i.UTXO = NevCoin.UTXOs.get(i.transactionOutputId);
+        }
+
+        if (getInputsValue() < NevCoin.minimumTransaction) {
+            System.out.println("#Transaction Inputs to small: " + getInputsValue());
+            return false;
+        }
+
+        float leftOver = getInputsValue() - value;
+        transactionId = calculateHash();
+        outputs.add(new TransactionOutput( this.recipient, value, transactionId));
+        outputs.add(new TransactionOutput( this.sender, leftOver, transactionId));
+
+        for (TransactionOutput o : outputs) {
+            NevCoin.UTXOs.put(o.id, o);
+        }
+
+        for (TransactionInput i : inputs) {
+            if (i.UTXO == null) continue; //if Transaction can't be found skip it
+            NevCoin.UTXOs.remove(i.UTXO.id);
+        }
+
+        return true;
+    }
+
+    public float getInputsValue() {
+        float total = 0;
+        for (TransactionInput i : inputs) {
+            if (i.UTXO == null) continue; //if Transaction can't be found skip it
+            total += i.UTXO.value;
+        }
+        return total;
+    }
+
+    public void generateSignature(PrivateKey privateKey) {
+        String data = StringUtil.getStringFromKey(sender) + StringUtil.getStringFromKey(recipient) + Float.toString(value)	;
+        signature = StringUtil.applyECDSASig(privateKey, data);
+    }
+
+    public boolean verifySignature() {
+        String data = StringUtil.getStringFromKey(sender) + StringUtil.getStringFromKey(recipient) + Float.toString(value)	;
+        return StringUtil.verifyECDSASig(sender, data, signature);
+    }
+
+    public float getOutputsValue() {
+        float total = 0;
+        for(TransactionOutput o : outputs) {
+            total += o.value;
+        }
+        return total;
+    }
+
+    private String calculateHash() {
+        sequence++;
+        return StringUtil.applySha256(
+                StringUtil.getStringFromKey(sender)
+                + StringUtil.getStringFromKey(recipient)
+                + Float.toString(value) + sequence
+        );
+    }
+}
--- a/src/main/java/tech/nevets/nevcoin/transactions/TransactionInput.java
+++ b/src/main/java/tech/nevets/nevcoin/transactions/TransactionInput.java
@ -0,0 +1,11 @@
+package tech.nevets.nevcoin.transactions;
+
+public class TransactionInput {
+
+    public String transactionOutputId;
+    public TransactionOutput UTXO;
+
+    public TransactionInput(String transactionOutputId) {
+        this.transactionOutputId = transactionOutputId;
+    }
+}
--- a/src/main/java/tech/nevets/nevcoin/transactions/TransactionOutput.java
+++ b/src/main/java/tech/nevets/nevcoin/transactions/TransactionOutput.java
@ -0,0 +1,22 @@
+package tech.nevets.nevcoin.transactions;
+
+import tech.nevets.nevcoin.util.StringUtil;
+import java.security.PublicKey;
+
+public class TransactionOutput {
+    public String id;
+    public PublicKey recipient;
+    public float value;
+    public String parentTransactionId;
+
+    public TransactionOutput(PublicKey recipient, float value, String parentTransactionId) {
+        this.recipient = recipient;
+        this.value = value;
+        this.parentTransactionId = parentTransactionId;
+        this.id = StringUtil.applySha256(StringUtil.getStringFromKey(recipient) + Float.toString(value)+parentTransactionId);
+    }
+
+    public boolean isMine(PublicKey publicKey) {
+        return (publicKey == recipient);
+    }
+}
--- a/src/main/java/tech/nevets/nevcoin/util/StringUtil.java
+++ b/src/main/java/tech/nevets/nevcoin/util/StringUtil.java
@ -0,0 +1,92 @@
+package tech.nevets.nevcoin.util;
+
+import com.google.gson.GsonBuilder;
+import tech.nevets.nevcoin.transactions.Transaction;
+
+import java.security.*;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.List;
+
+public class StringUtil {
+
+    public static String applySha256(String input) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            byte[] hash = digest.digest(input.getBytes("UTF-8"));
+            StringBuffer hexString = new StringBuffer();
+
+            for (int i = 0; i < hash.length; i++) {
+                String hex = Integer.toHexString(0xff & hash[i]);
+
+                if (hex.length() == 1) hexString.append('0');
+                hexString.append(hex);
+            }
+            return hexString.toString();
+
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static byte[] applyECDSASig(PrivateKey privateKey, String input) {
+        Signature dsa;
+        byte[] output = new byte[0];
+        try {
+            dsa = Signature.getInstance("ECDSA", "BC");
+            dsa.initSign(privateKey);
+            byte[] strByte = input.getBytes();
+            dsa.update(strByte);
+            byte[] realSig = dsa.sign();
+            output = realSig;
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+        return output;
+    }
+
+    public static boolean verifyECDSASig(PublicKey publicKey, String data, byte[] signature) {
+        try {
+            Signature ecdsaVerify = Signature.getInstance("ECDSA", "BC");
+            ecdsaVerify.initVerify(publicKey);
+            ecdsaVerify.update(data.getBytes());
+            return ecdsaVerify.verify(signature);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static String getJson(Object o) {
+        return new GsonBuilder().setPrettyPrinting().create().toJson(o);
+    }
+
+    public static String getDifficultyString(int difficulty) {
+        return new String(new char[difficulty]).replace('\0', '0');
+    }
+
+    public static String getStringFromKey(Key key) {
+        return Base64.getEncoder().encodeToString(key.getEncoded());
+    }
+
+    public static String getMerkleRoot(ArrayList<Transaction> transactions) {
+        int count = transactions.size();
+
+        List<String> previousTreeLayer = new ArrayList<String>();
+        for (Transaction transaction : transactions) {
+            previousTreeLayer.add(transaction.transactionId);
+        }
+        List<String> treeLayer = previousTreeLayer;
+
+        while (count > 1) {
+            treeLayer = new ArrayList<String>();
+            for(int i=1; i < previousTreeLayer.size(); i += 2) {
+                treeLayer.add(applySha256(previousTreeLayer.get(i - 1) + previousTreeLayer.get(i)));
+            }
+            count = treeLayer.size();
+            previousTreeLayer = treeLayer;
+        }
+
+        String merkleRoot = (treeLayer.size() == 1) ? treeLayer.get(0) : "";
+        return merkleRoot;
+    }
+}