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Author: kevinjycui

.gitignore

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+Forensics/shark on wire 2/

Cryptography/13/README.md

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+# 13
+Points: 100
+## Category
+Cryptography
+## Problem Statement
+> Cryptography can be easy, do you know what ROT13 is? `cvpbPGS{abg_gbb_onq_bs_n_ceboyrz}`
+## Hints
+> This can be solved online if you don't want to do it by hand!
+## Solution
+ROT13 is a simple cipher that replaces every character with the character 13 characters ahead of it in the alphabet. As the hint tells us, the easiest way to do this is using an online tool such as [rot13.com](https://rot13.com/).
+## Flag
+`picoCTF{not_too_bad_of_a_problem}`

Cryptography/Easy1/README.md

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+# Easy1
+Points: 100
+## Category
+Cryptography
+## Problem Statement
+> The one time pad can be cryptographically secure, but not when you know the key. Can you solve this? We've given you the encrypted flag, key, and a table to help `UFJKXQZQUNB` with the key of `SOLVECRYPTO`. Can you use this [table](table.txt) to solve it?.
+## Hints
+> Submit your answer in our competition's flag format. For example, if you answer was 'hello', you would submit 'picoCTF{HELLO}' as the flag.
+> Please use all caps for the message.
+## Solution
+A key and a double-entry table immediatly clues us to one of the most common encryption methods: the Vigenère cipher. While there are ways to decrypt messages with this cipher manually (using the table in the given text file), it is much easier to solve it with on online tool such as [DCODE](https://www.dcode.fr/vigenere-cipher).
+## Flag
+`picoCTF{CRYPTOISFUN}`

Cryptography/Easy1/table.txt

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+    A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
+   +----------------------------------------------------
+A | A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
+B | B C D E F G H I J K L M N O P Q R S T U V W X Y Z A
+C | C D E F G H I J K L M N O P Q R S T U V W X Y Z A B
+D | D E F G H I J K L M N O P Q R S T U V W X Y Z A B C
+E | E F G H I J K L M N O P Q R S T U V W X Y Z A B C D
+F | F G H I J K L M N O P Q R S T U V W X Y Z A B C D E
+G | G H I J K L M N O P Q R S T U V W X Y Z A B C D E F
+H | H I J K L M N O P Q R S T U V W X Y Z A B C D E F G
+I | I J K L M N O P Q R S T U V W X Y Z A B C D E F G H
+J | J K L M N O P Q R S T U V W X Y Z A B C D E F G H I
+K | K L M N O P Q R S T U V W X Y Z A B C D E F G H I J
+L | L M N O P Q R S T U V W X Y Z A B C D E F G H I J K
+M | M N O P Q R S T U V W X Y Z A B C D E F G H I J K L
+N | N O P Q R S T U V W X Y Z A B C D E F G H I J K L M
+O | O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
+P | P Q R S T U V W X Y Z A B C D E F G H I J K L M N O
+Q | Q R S T U V W X Y Z A B C D E F G H I J K L M N O P
+R | R S T U V W X Y Z A B C D E F G H I J K L M N O P Q
+S | S T U V W X Y Z A B C D E F G H I J K L M N O P Q R
+T | T U V W X Y Z A B C D E F G H I J K L M N O P Q R S
+U | U V W X Y Z A B C D E F G H I J K L M N O P Q R S T
+V | V W X Y Z A B C D E F G H I J K L M N O P Q R S T U
+W | W X Y Z A B C D E F G H I J K L M N O P Q R S T U V
+X | X Y Z A B C D E F G H I J K L M N O P Q R S T U V W
+Y | Y Z A B C D E F G H I J K L M N O P Q R S T U V W X
+Z | Z A B C D E F G H I J K L M N O P Q R S T U V W X Y
+

Cryptography/Flags/README.md

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+# Flags
+Points: 200
+## Category
+Cryptography
+## Problem Statement
+> What do the [flags](flag.png) mean?
+## Hints
+> The flag is in the format PICOCTF{}
+## Solution
+When we view this image, we see a sequence of decorated squares. Upon seeing this, any navy enthusiast would immediately recognise the Internation Code of Signals. These signals are a common type of maritime flag signalling cryptography. Simply decode the signals to their respective uppercase characters and get the flag.
+![Screenshot](screenshot.JPG)
+## Flag
+`PICOCTF{F1AG5AND5TUFF}`

Cryptography/Flags/flag.png

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+# Tapping
+Points: 200
+## Category
+Cryptography
+## Problem Statement
+> Theres tapping coming in from the wires. What's it saying `nc 2019shell1.picoctf.com 49914`.
+## Hints
+> What kind of encoding uses dashes and dots?
+> The flag is in the format PICOCTF{}
+## Solution
+After connecting to this port, we are given a sequence of dots and dashes as so:
+```
+.--. .. -.-. --- -.-. - ..-. { -- ----- .-. ... ...-- -.-. ----- -.. ...-- .---- ... ..-. ..- -. ----. ----- ...-- .---- ....- ----- ....- ....- ---.. } 
+```
+This allows us to deduce that the method of encryption is one of the most well-known types of cryptography: morse code. If you are proficient with morse, feel free to crack it yourself. Otherwise, an online tool such as [unit-conversion.info](http://www.unit-conversion.info/texttools/morse-code/) will do.
+## Flag
+`PICOCTF{M0RS3C0D31SFUN903140448}`

Cryptography/Flags/screenshot.JPG

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+# The Numbers
+Points: 50
+## Category
+Cryptography
+## Problem Statement
+> The [numbers](the_numbers.png)... what do they mean?
+## Hints
+> The flag is in the format PICOCTF{}
+## Solution
+When we manually open this file and simply look at the image, we can see that there are a sequence of numbers. We can quickly realise that these numbers are never below 1 and never exceed 26. When we manually find the characters at each index in the alphabet in uppercase, we get our flag. We could also use a basic script such as [this](the_numbers.py) to get the flag.
+## Flag
+`PICOCTF{THENUMBERSMASON}`