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* Cryptic message with a hint in the challenge description or title
* Deeper concepts require a good knowledge of mathematics
* Rotation ciphers are a starting point
</script></section><section data-markdown><script type="text/template">
### ROTN

* Encryption by shifting each character by N places to the right
* Most popular - **ROT13** aka Caesar Cipher

$$E_n(x) = (x+n) mod 26$$

$$E_n^\prime(x) = D_n(x) = (x-n) mod 26$$
</script></section><section data-markdown><script type="text/template">
### Challenge #4

* Caesar cipher
* Base64
**Encrypted message:** (HEX)

`170d05080a0d0c0a19010a06041e06020a19`

**Encryption Key:** (HEX)

`6468696e6368616b706f6f6a61726f636b73`

**Encryption Method:**

`XOR`

Decrypt the message
</script></section><section data-markdown><script type="text/template">
### Solution

**Property of XOR:**

1. $$a \oplus a = 0$$

2. $$a \oplus 0 = a$$
</script></section><section data-markdown><script type="text/template">
$$\implies msg \oplus key \oplus key = msg$$

XOR the encrypted message with the key again to get the original message again

`73656c6669656d61696e656c656c6961616a`
</script></section></section><section ><section data-markdown><script type="text/template">
### OSINT

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</script></section><section data-markdown><script type="text/template">
### Challenge #6

* You are presented with a quiz website
* 1000Q, single right answer
* Wrong answer resets your score BUT
* Also provides with the right answer
* You are given a large chunk of text worth easily over 100MB

```
akOjas;kdfjFs;kdfjasFkfja;kfajf;kIjfdkjCfkafEk
weruqwIeuqworieuSwoeruqperuqpweruqTeriuqwpHerw
zmnEcv,mncv,mznvzvnzvBvnzvnzmvnzmcvnzExvbzcvbs
qwemSnq,embrtjThvovchzoivucTaanfamfdnqVewnrucp
ewnSqmnrzhvcHicvuapiuasdfna.OenrqwmenrjhWziocu
```
</script></section><section data-markdown><script type="text/template">
## HINT

* Anything odd?

```
akOjas;kdfjFs;kdfjasFkfja;kfajf;kIjfdkjCfkafEk
weruqwIeuqworieuSwoeruqperuqpweruqTeriuqwpHerw
zmnEcv,mncv,mznvzvnzvBvnzvnzmvnzmcvnzExvbzcvbs
qwemSnq,embrtjThvovchzoivucTaanfamfdnqVewnrucp
ewnSqmnrzhvcHicvuapiuasdfna.OenrqwmenrjhWziocu
```
</script></section><section data-markdown><script type="text/template">
### Solution

* Automated web-scraping
* Enter a random answer and collect all the right answers with their questions
* This time, get the question, find its answer and enter it
* Notice that the capital letters form something meaningful
* Some ezpz programming with ASCII values
* Extracted capital letter form this:

```
OFFICEISTHEBESTTVSHOW
```
</script></section></section><section data-markdown><script type="text/template">
## Practice sites

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* styling with CSS
* creating your webpage from scratch

then, **Jekyll** is your friend
then, [**Jekyll**](https://github.com/topics/jekyll-theme) is your friend
</script></section><section data-markdown><script type="text/template">
* Write content in markdown and Jekyll will generate the HTML for it
* **GitHub pages** offers free and easy hosting solution for static websites
* Check out `jekyll-themes` on GitHub for amazing repos and sites
</script></section></section></div>
</div>

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