new file: Codecademy/helloworld.c

new file:   Codedex/Python/19-Detention.py
new file:   Codedex/Python/20-99.bottles.py
new file:   Codedex/Python/21-Fizz-Buzz.py
new file:   Cryptohack/xor-properties.py
deleted:    Cryptohack/xor-str.py
new file:   Pwn.college/Program-interaction/28.py
new file:   Pwn.college/Program-interaction/29.c
new file:   Pwn.college/Program-interaction/30.c

Author: TheRealFREDP3D

Codecademy/helloworld.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+/*
+This code snippet is written in C and defines a program that outputs 
+the text "Hello World!" to the console. It includes the standard 
+input-output library stdio.h and defines a main function. 
+Inside the main function, it uses the printf function to print the message 
+"Hello World!" followed by a newline character \n.
+*/
+
+int main() {
+  // output a line
+  printf("Hello World!\n");
+}

Codedex/Python/19-Detention.py

@@ -0,0 +1,4 @@
+# detention.py
+
+for i in range(100):
+  print('I will not use Snapchat in class')

Codedex/Python/20-99.bottles.py

@@ -0,0 +1,7 @@
+# 99 Bottles of beer song
+
+for bottle in range(99, 0, -1):
+  print(f'{bottles} bottles of beer on the wall')
+  print(f'{bottles} of beer')
+  print('Take one down, pass it around')
+  

Codedex/Python/21-Fizz-Buzz.py

@@ -0,0 +1,15 @@
+"""
+# 21-Fizz-Buzz.py
+
+Prints the numbers from 1 to 99, replacing multiples of 3 with "Fizz", multiples of 5 with "Buzz", 
+and multiples of both 3 and 5 with "FizzBuzz".
+"""
+for i in range(1, 100, 1):
+    if (i % 3 == 0) and (i % 5 == 0) == True:
+        print("FizzBuzz")
+    elif i % 3 == 0:
+        print("Fizz")
+    elif i % 5 == 0:
+        print("Buzz")
+    else:
+        print(f"{i}")

Cryptohack/xor-properties.py

@@ -0,0 +1,7 @@
+from pwn import xor
+
+k1=bytes.fromhex('a6c8b6733c9b22de7bc0253266a3867df55acde8635e19c73313')
+k2_3=bytes.fromhex('c1545756687e7573db23aa1c3452a098b71a7fbf0fddddde5fc1')
+flag=bytes.fromhex('04ee9855208a2cd59091d04767ae47963170d1660df7f56f5faf')
+
+print(xor(k1,k2_3,flag))

Cryptohack/xor-str.py

@@ -0,0 +1,10 @@
+# - the challenge checks for a specific parent process : python
+# - the challenge will check that the environment is empty (except LC_CTYPE, which is impossible to get rid of in some cases)
+
+import subprocess
+result = subprocess.check_output(
+    ["/challenge/embryoio_level28"],
+    env={"LC_CTYPE": "C"},
+    stderr=subprocess.STDOUT
+)
+print(result.decode("utf-8"))

Pwn.college/Program-interaction/28.py

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+void pwncollege(char *argv[], char *env[])
+{
+    execve("/challenge/embryoio_level29", argv, env);
+}
+
+int main(int argc, char *argv[], char *env[])
+{
+    pid_t fpid;
+
+    fpid = fork();
+// Create a fork and save the PID, PID 0 will be child process which is what we want to wait on
+
+        if (fpid == 0)
+    { // If we are onto the child process
+        pwncollege(argv, env);
+    }
+    else
+    {
+        waitpid(fpid, NULL, 0); // Wait for child process to run before parent terminates *HINT* wait literally waits for the child process before terminating the parent.. that is what it does
+    }
+    return 0;
+}

Pwn.college/Program-interaction/29.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+void pwncollege(char *argv[], char *env[])
+{
+    execve("/challenge/embryoio_level30", argv, env);
+}
+
+int main(int argc, char *argv[], char *env[])
+{
+    pid_t fpid;
+
+    fpid = fork();
+// Create a fork and save the PID, PID 0 will be child process which is what we want to wait on
+
+        if (fpid == 0)
+    { // If we are onto the child process
+        pwncollege(argv, env);
+    }
+    else
+    {
+        waitpid(fpid, NULL, 0); // Wait for child process to run before parent terminates *HINT* wait literally waits for the child process before terminating the parent.. that is what it does
+    }
+    return 0;
+}