James Christie PR

.gitignore

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+Day_1/C++/**.o
+Day_1/C++/**.txt
+**/C#/bin/**
+**/C#/obj/**
+**/rust/target/**
+Day_2/rust/**
+**.html

.vscode/settings.json

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+{
+    "files.associations": {
+        "unordered_map": "cpp",
+        "ostream": "cpp",
+        "iosfwd": "cpp"
+    },
+    "python.pythonPath": "/usr/bin/python3"
+}

Day_1/C#/C#comphash.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <RootNamespace>C_comphash</RootNamespace>
+  </PropertyGroup>
+
+</Project>

Day_1/C#/Program.cs

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+using System;
+using System.Net;
+using System.Text.RegularExpressions;
+
+namespace C_comphash
+{
+    class Program {
+        const string charpool = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+        const int pwd_length = 4;
+        class strgen {
+            int[] state;
+            public strgen(){
+                state = new int[pwd_length];           
+            }
+            public string next() {
+                string ret = "";
+                for(int i = 0; i < pwd_length; i++) {
+                    ret += charpool[state[i] % 62];
+                }
+                for(int i = 0; i < pwd_length; i++){
+                    if (state[i] < 62) {
+                        state[i] += 1;
+                        break;
+                    } else {
+                        state[i] = 0;
+                    }
+                }
+                return ret;
+            }
+        }
+        static void Main(string[] args) {
+            // get the target hash from file
+            string target_hash = System.IO.File.ReadAllText("../data/targethash.txt");
+            Console.WriteLine(target_hash);
+
+            // use this to generate possible strings
+            strgen generator = new strgen();
+            string t_string;
+
+            // hashing object
+            var MD5 = System.Security.Cryptography.MD5.Create();
+
+            System.Text.StringBuilder sb = new System.Text.StringBuilder();
+            byte[] t_bytes;
+            byte[] hashed;
+            // now compute hashes and test
+            while(true){
+                t_string = generator.next();
+                t_bytes = System.Text.Encoding.ASCII.GetBytes(t_string);
+                hashed = MD5.ComputeHash(t_bytes);
+
+                // convert the hashed bytes into a string
+                // splits the bytes into low and high nibbles
+                for (int i = 0; i < hashed.Length; i++) {
+                    sb.Append(hashed[i].ToString("x2"));
+                }
+                if (sb.ToString().Equals(target_hash)) {
+                    break;
+                }
+                sb.Clear();
+            }
+
+            // echo what we found
+            Console.WriteLine($"String with the given hash {target_hash} is {t_string}");
+            // download the final url 
+            WebClient client = new WebClient();
+            string htmlstring = client.DownloadString($"https://tiny.utk.edu/{t_string}");
+            System.IO.File.WriteAllText("../data/page.html", htmlstring);
+
+            // we know it's a gist based on the HTML we got, let's get the raw address
+            Regex regex = new Regex("href=\"(.+raw.+?)\"", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+            string matchstr = "";
+            foreach(Match match in regex.Matches(htmlstring))
+            {
+                matchstr += match.Groups[1].Value;
+            }
+            client.DownloadFile($"https://gist.github.com/{matchstr}", "../data/FourVectorTest.csv");
+        }
+    }
+}

Day_1/C#/Usage.md

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+To use this, you'll need .net version > 2 installed. Once that is done, cd into the C# directory and do
+```
+dotnet build
+dotnet run
+```
+if this doesn't work, I've borked something with the upload.

Day_1/C++/clangbuild.sh

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+clang++ -l ssl -l crypto comphash.cpp -O3 -v -o comphash.o  2> builderr.txt 

Day_1/C++/comphash.cpp

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+#include <openssl/md5.h>
+#include <string.h>
+#include <iostream>
+#include <fstream>
+#include <map>
+#include <sstream>
+#include <boost/format.hpp>
+
+// how long is the hashed value?
+const int pwd_length = 4;
+
+// pool of characters for making guesses
+const char *charpool = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+struct strgen
+{
+    int state[pwd_length];
+    strgen(){
+        for(int i = 0; i < pwd_length; i++) {
+            state[i] = 0;
+        }
+    };
+
+    std::string next() {
+        std::string ret = "";
+        for(int i = 0; i < pwd_length; i++) {
+            ret += charpool[state[i] % 62];
+        }
+        for(int i = 0; i < pwd_length; i++){
+            if (state[i] < 61) {
+                state[i] += 1;
+                break;
+            } else {
+                state[i] = 0;
+            }
+        }
+        return ret;
+    };
+};
+
+int main(void) {
+    std::string targetstr;
+    // get the target hash from the file
+    { 
+        std::ifstream ifs("../data/targethash.txt");
+        targetstr.assign( (std::istreambuf_iterator<char>(ifs) ), 
+                                    (std::istreambuf_iterator<char>()    ) );
+        ifs.close();
+    }
+
+    // generator for combinations
+    strgen generator = strgen();
+    std::string t_str = generator.next();
+    std::string first;
+    for(int i = 0; i < pwd_length; i++){
+        first.push_back(t_str[i]);
+    }
+    unsigned char hash[MD5_DIGEST_LENGTH];
+    while(true){
+        MD5((unsigned char *)t_str.c_str(), pwd_length, hash);
+        // this lovely mess can be blamed on my compiler not recognizing std::format()
+        std::string hashstr = (boost::format("%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x")%
+            (int)hash[0]%(int)hash[1]%(int)hash[2]%(int)hash[3]%
+            (int)hash[4]%(int)hash[5]%(int)hash[6]%(int)hash[7]%
+            (int)hash[8]%(int)hash[9]%(int)hash[10]%(int)hash[11]%
+            (int)hash[12]%(int)hash[13]%(int)hash[14]%(int)hash[15]).str();
+        //std::cout << hashstr << std::endl;
+        if (hashstr.compare(targetstr) == 0) {   
+            break;
+        }
+        // do after the loop body so that we can store it before the initial loop
+        t_str = generator.next();
+        // a little bit of insurance to prevent infinite loops
+        // could probably store this on the generator though
+        if (t_str.compare(first) == 0) {
+            std::cout << "failed to find hash" << std::endl;
+            return -1;
+        }
+    }
+
+    std::cout << "The string with the hash " << targetstr << " is " << t_str << std::endl;
+
+}

Day_1/C++/usage.md

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+To use this, from a terminal (bash, zsh, etc) do
+```sh
+source clangbuild.sh
+```
+
+Dependencies:
+boost (tested with 1.71)
+openssl (tested with 1.1.1f)