diff --git a/TODO.md b/TODO.md
deleted file mode 100644
index c134c63..0000000
--- a/TODO.md
+++ /dev/null
@@ -1,10 +0,0 @@
-# Things that tasks would be cool
-
-## Kryptography
-- [ ] Caesar-encryption, decryption, brute force
-
-## Math
-- [ ] calculate determinant of a matrix
-
-## General Tech
-- [ ] Regex
diff --git a/TODO.norg b/TODO.norg
new file mode 100644
index 0000000..411a4c1
--- /dev/null
+++ b/TODO.norg
@@ -0,0 +1,15 @@
+This is a list of tasks that would be cool to add.
+
+* Tasks
+** Basic
+*** Files
+ - ( ) Hex dumper
+*** Networking
+ - ( ) Mini curl
+*** Packaging
+ - ( ) Installing a package to your system
+ - ( ) Building a library
+
+** Cryptography
+*** Signature
+ - ( ) Check a signature with OpenSSL
diff --git a/Tasks.md b/Tasks.md
index 9dd9c6b..af34fd8 100644
--- a/Tasks.md
+++ b/Tasks.md
@@ -1,11 +1,11 @@
# Tasks for beginners
-This document contains some tasks for Python beginners. It does not aim to teach general
+This document contains some tasks for Python beginners. It does not aim to teach general
programming techniques, only how to use Python. I try to avoid unrealistic tasks.
-In case you have somehow gotten this document from another source,
-[this](https://git.cscherr.de/PlexSheep/py-basic/src/branch/master/Tasks.md) is the original
-source, where the links should hopefully work. If something does not work feel free to contact
+In case you have somehow gotten this document from another source,
+[this](https://git.cscherr.de/PlexSheep/py-basic/src/branch/master/Tasks.md) is the original
+source, where the links should hopefully work. If something does not work feel free to contact
me at [software@cscherr.de](mailto:admin@cscherr.de).
## MD5 Hashchecker
@@ -22,7 +22,7 @@ Difficulty: 1/5
- Use Pythons `hashlib`.
- Your hashing function does not take strings for input, only raw data (bytes).
- You need to explicitly tell your hash to actually process the input.
-- When printing your results, the result may be interpreted as data for characters.
+- When printing your results, the result may be interpreted as data for characters.
You want the numeric value of the result in Hexadecimal.
@@ -39,7 +39,7 @@ The MD5 hash of `foobar19` is `fa5c65d5438f849387d3fdda2be4dd65`.
Difficulty: 2/5
-1. Find a way to produce strings with the basis `foobar` with appended numbers from `000000` to
+1. Find a way to produce strings with the basis `foobar` with appended numbers from `000000` to
`999999`.
```text
@@ -53,8 +53,8 @@ Difficulty: 2/5
2. Hash all these with the MD5 hashing algorithm.
3. Find the exact numbers, how many of these hashes start with `00`
-4. **Bonus**:
- 1. If MD5 was a good / perfect Hashing algorithm (it is definitely not),
+4. **Bonus**:
+ 1. If MD5 was a good / perfect Hashing algorithm (it is definitely not),
how many matches for a `00` prefix should exist? Why?
2. How many matches for $0$ to $50000$? How many matches for $0$ to $50.000.000$?
@@ -78,7 +78,7 @@ Last 5 Matches
- Use a for loop to do the thing X times
- Use Pythons string formatting to put the numbers and string together
- Use Options for the `%d` Placeholder to get $0$ to be displayed as `000000`
-- After hashing, check if your current hash matches the search.
+- After hashing, check if your current hash matches the search.
Print it if that is the case to see if the match is a false positive.
- Increment a number on each match. The value of that number after the loop is how many
Hashes start with `00` for this task.
@@ -87,19 +87,19 @@ Last 5 Matches
Solution
-There are 3889 hashes for `foobar000000` to `foobar999999` that produce an MD5 Hash that starts
+There are 3889 hashes for `foobar000000` to `foobar999999` that produce an MD5 Hash that starts
with `00`.
[Code Example](src/md5range.py)
-**Bonus**
-We want $N/16^2$ occurrences for an ideal hashing algorithm, where $N$ is the maximum of our range
-$+ 1$.
+**Bonus**
+We want $N/16^2$ occurrences for an ideal hashing algorithm, where $N$ is the maximum of our range
+$+ 1$.
$16^2$ comes from $2$ characters in a range of `0` to `e` (Hexadecimal).
-We want the hashing algorithm to spread out as much as possible, no value should be more common
-than any other value. This is essential for the security of the hashing algorithm.
+We want the hashing algorithm to spread out as much as possible, no value should be more common
+than any other value. This is essential for the security of the hashing algorithm.
| Value | Ideal Occurences |
|--------------|------------------|
@@ -113,14 +113,14 @@ than any other value. This is essential for the security of the hashing algorith
Difficulty: 2/5
-1. Find the earliest integer $X$ for `foobarXXXXXX` (where $X$ is an iterator as in the last
+1. Find the earliest integer $X$ for `foobarXXXXXX` (where $X$ is an iterator as in the last
subtask) that produces an MD5 hash that starts with `2718`.
Hints
- You can reuse most code from the last subtask.
-- Match against the new prefix, but stop when you find it.
+- Match against the new prefix, but stop when you find it.
- Display the index number in each loop iteration.
@@ -150,8 +150,8 @@ Difficulty: 3/5
- Use `http.server.SimpleHTTPRequestHandler` and `io.BytesIO`.
- Define your own class that inherits `SimpleHTTPRequestHandler`.
- You don't need to implement `do_GET()`.
-- Implement your own `send_head()` method. This is the method that writes your response (not
- completely on it's own, but unless you feel like inspecting standard libraries, just do what
+- Implement your own `send_head()` method. This is the method that writes your response (not
+ completely on it's own, but unless you feel like inspecting standard libraries, just do what
I'm saying.).
- `send_head()` should take no arguments (other than `self`) and return some readable buffer.
- Don't forget to set the headers for HTTP before sending the body.
@@ -172,13 +172,13 @@ Take a look at the provided Code Example.
Difficulty: 2/5
1. Generate a string of 16 random alphanumeric characters.
-2. When starting your script, take a number for a CLI Argument. Generate a random string of this
+2. When starting your script, take a number for a CLI Argument. Generate a random string of this
length.
3. **Bonus**
- How many possible strings consisting of 16 alphanumeric characters can exist?
- - Add the possibility for a second argument `-v` that indicates your script should be more
+ - Add the possibility for a second argument `-v` that indicates your script should be more
verbose.
- - print the security bits ($log_2(L)$ where $L$ is the total number of possibilites) when the
+ - print the security bits ($log_2(L)$ where $L$ is the total number of possibilities) when the
`-v` flag is applied
Example:
@@ -211,21 +211,21 @@ There are 62 alphanumeric characters (A-Z), (a-z), (0-9).
With $N$ characters, there are $62^N$ possible variants.
For $N=16$ that's $62^{16} = 47.672.401.706.823.533.450.263.330.816$ possible variants.
-Security people measure security in Bits ($2^x$). You can calculate the bits of security with the
+Security people measure security in Bits ($2^x$). You can calculate the bits of security with the
logarithm base 2.
-$S = log_2(62^N)$.
+$S = log_2(62^N)$.
We can immediately see that longer passwords are *exponentially* more secure than
-more complex passwords (passwords that make use of complicated characters). For each bit, the
+more complex passwords (passwords that make use of complicated characters). For each bit, the
security of the password is doubled.
For our example of $N=16$ we can calculate the security of the password like this:
$S=log_2(62^{16}) \approx 95.27$
-That number of security bits is pretty good for passwords. However it does not cost you anything to
-just make your passwords longer than that, and give attackers no chance to break them by brute
+That number of security bits is pretty good for passwords. However it does not cost you anything to
+just make your passwords longer than that, and give attackers no chance to break them by brute
force.
@@ -237,14 +237,14 @@ Difficulty: 2/5
Text
-The text is large, read it [here](data/metasyntactic.md) and find the raw text for your program
+The text is large, read it [here](data/metasyntactic.md) and find the raw text for your program
[here](https://git.cscherr.de/PlexSheep/py-basic/raw/branch/master/data/metasyntactic.md).
1. Use a regular expression (regex) to find all words that start with a lowercase character with a
following vowel character, in which no 'x', z' or 'y' follows the vowel in the given Text.
-It is not allowed to store the text in source code, you must load it from an outside source,
+It is not allowed to store the text in source code, you must load it from an outside source,
such as a file.
Examples:
@@ -260,7 +260,7 @@ Examples:
| bAR | yes |
| far | yes |
-A hint that you don't want to miss:
+A hint that you don't want to miss:
Use [regex101.com](https://regex101.com) if you are not already a REGEX expert.
@@ -287,3 +287,78 @@ A regex that fullfills the requirements is `\b[a-z][AEIOUaeiou]([a-w]|[A-W])`.
[Code Example](src/tasks/regex.py)
+
+## Making a Hexeditor
+
+In this section, we're building a little hexeditor. You will be able to install
+it on your system and use it instead of the `hexdump` and `xxd` built into most
+Linux distributions.
+
+Hexdumping is actually really simple, all you have to do is read a file and
+print it's direct content interpreted as numbers in hexadecimal. Apply some
+fancy string formatting and we're done!
+
+The editing part is a lot harder. It requires us to build a functioning TUI -
+Terminal User Interface, as working with command line arguments or regular
+reading from stdin won't help us much for editing a file. (if that's your thing,
+use `ed`.).
+
+Note: If you're looking for a great, fully featured hexeditor, I'd recommend
+`bvi` ("binary vi"), which is packaged by most distributions.
+
+-> `apt-get install bvi`
+
+Note: I have no Idea how to install a python script as executable on windows, I
+don't like windows either, so no support for installing stuff on windows.
+
+### A. Hexdumper
+Difficulty: 2/5
+
+
+1. Dump the data of [data/metasyntactic.md](./data/metasyntactic.md) -- In
+ Hexadecumal.
+2. Make the dumped Bytes look pretty, something like the example below:
+
+
+ Hexdump Example Display
+
+`data/metasyntactic.md` looks like this when hexdumped:
+
+```text
+Line Data
+=================================================
+0000000 ┃ 6f4e 6574 203a 6854 7369 6920 2073 6874
+0000010 ┃ 2065 6957 696b 6570 6964 2061 6170 6567
+0000020 ┃ 6620 726f 6d20 7465 7361 6e79 6174 7463
+0000030 ┃ 6369 7620 7261 6169 6c62 7365 6920 206e
+0000040 ┃ 6e45 6c67 7369 2c68 3220 3230 2d33 3930
+0000050 ┃ 302d 2e35 4620 6e69 2064 6874 0a65 7075
+0000060 ┃ 7420 206f 6164 6574 6f20 6972 6967 616e
+0000070 ┃ 206c 685b 7265 5d65 6828 7474 7370 2f3a
+0000080 ┃ 652f 2e6e 6977 696b 6570 6964 2e61 726f
+0000090 ┃ 2f67 6977 696b 4d2f 7465 7361 6e79 6174
+00000a0 ┃ 7463 6369 765f 7261 6169 6c62 2965 0a2e
+00000b0 ┃ 230a 4d20 7465 7361 6e79 6174 7463 6369
+00000c0 ┃ 7620 7261 6169 6c62 0a65 230a 2023 6f54
+00000d0 ┃ 6c6f 0a73 460a 6f72 206d 6957 696b 6570
+00000e0 ┃ 6964 2c61 7420 6568 6620 6572 2065 6e65
+00000f0 ┃ 7963 6c63 706f 6465 6169 540a 6968 2073
+0000100 ┃ 7261 6974 6c63 2065 7369 6120 6f62 7475
+0000110 ┃ 6d20 7465 7361 6e79 6174 7463 6369 7620
+...
+```
+
+
+Hints
+
+TODO: add hints
+
+
+
+Solution
+
+TODO: formulate solution text
+
+[Code Example](src/tasks/hexdumper-a.py)
+
+
diff --git a/src/tasks/hexdumper-a.py b/src/tasks/hexdumper-a.py
new file mode 100755
index 0000000..7303f72
--- /dev/null
+++ b/src/tasks/hexdumper-a.py
@@ -0,0 +1,8 @@
+#!/usr/bin/env python3
+import sys
+
+def main():
+ # parse args
+
+if __name__ == "__main__":
+ main()