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Cryptography ctf by Avi

Brain fuck and reverse brain fuck cypher: 

https://www.dcode.fr/brainfuck-language

++++++++++[>+>+++>+++++++>++++++++++<<<<-]>>>>++++++++++++.<------------------.>+++..++++.--------.+++.--------------.+++++.++++++++++.-----.+.+++++.------------.<---.>----..+.+++++++++.

The reverse brain fuck starts with the - (minus) sign.

https://www.dcode.fr/langage-reversefuck

----------]<-<---<-------<---------->>>>+[<<<+++,<---------------------,+++++++++++++++++++++++,---,-------------,++++++++++++++++,+,-------------,+++++++,-----,+++++++++++,--------------------------,>-------------,<++,+++++,++++++++++++,-------,+,>>--,<<+++++,----------,>>,<<+++++++++++++++++,---,--------------,-,>>,<<++++,--,+++,++++++++,-----------,>-----------------,<+++++,++++,-----,>------,>,<<++,>++++++,<--,>------,<-------,>++++++,------,++,<--------,

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 Twin-hex encoder/decoder

https://www.calcresult.com/misc/cyphers/twin-hex.html

https://www.calcresult.com/misc/cyphers/twin-hex.html?fbclid=IwAR01RuXBGaYEPmvp2BNaSaFFSq6MRM8RFnp0ydVZZ0tKizMs70fN2LiyoBY

3836rt4p05wf3gv69r3bj6f94pl5x14pa5wt4vi6w0 à twin-hex string

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Caesar cypher:

https://www.nayuki.io/page/automatic-caesar-cipher-breaker-javascript

https://www.xarg.org/tools/caesar-cipher/

These are also called ROT cyphers. (ROT 13/47)

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Enigma machine:


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md5 hash decryptor:


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Cypher identifier:



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CyberChef for lots of cypher decode:


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L33T 1337 L337 encryption:

http://www.robertecker.com/hp/research/leet-converter.php?lang=en

https://www.dcode.fr/leet-speak-1337

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Gravity Falls bill cypher:

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Wingdings font cypher:










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base 36 cypher alphanumerals:



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One-time pad cryptography:

https://www.boxentriq.com/code-breaking/one-time-pad

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Vigenere cipher decoder:

https://www.guballa.de/vigenere-solver

In this type of cypher, a decryption key is given. 

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Binary to ASCII converter:

https://mothereff.in/binary-ascii

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Decimal>hex>ascii

581695969015253365094191591547859387620042736036246486373595515576333693

decimal to ascii converter

85 110 112 97 99 107 32 116 104 105 115 32 66 67 68

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Soundcloud:

Soundcloud audio converter then downloads

https://www.klickaud.co/

Speech to text demo

https://speech-to-text-demo.ng.bluemix.net/

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XOR:

S1: 44585d6b2368737c65252166234f20626d

S2: 1010101010101010101010101010101010

After hex the S1 from cyberchef we shall get an encrypted code. Then we need to XOR that encrypted code using S2 as key. 

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Morse code:

Morse code audio decoder online:

https://morsecode.world/international/decoder/audio-decoder-adaptive.html

 - . .-.. . -.-. --- -- -- ..- -. .. -.-. .- - .. --- -.

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Bacon cipher:

A= not bold

B= bold



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Alphabetical Substitution cipher:

Xbyviyzmtoz{Zoozs rh Lmob Lmv}

Generally, small cypher is given like, XVGSTR

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Atbash mirror cipher:

Atbash cipher

Xbyviyzmtoz{Zoozs rh Lmob Lmv}

Xbyviyzmtoz{zgyzhs_rh_zohl_pmldm_zh_nriili_xrksvi}

Note: alphabetical substitution cypher and atbash cypher might give the same result sometimes. And atbash cypher starts from the end. 

ABCDEFGHIJKLMNOPQRSTUVWXYZ

ZYXWVUTSRQPONMLKJIHGFEDCBA

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Rail fence cipher:

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Encoding:

Base-32/58/32/64

echo "4ziTFWdzXc" | base58 -d

echo “7jVMLrWDJYbRiCkpEiHFKTdxp1papAFCg6rukKLnFszLUg7W” | base58 -d 

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Tap code:

.. .... .... .... .... ... .... .... . . ... ..... . ..... . ... ... .... . .... . .....

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Emoji cypher:

























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JS fuck cypher / language:
































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Sometimes you need to decode a hex value. The decoding result may come as garbage. But you need to then xor that if the author gives any key. We know in xor, a key is needed. 

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Deep Sound:
 
In order to solve audio related ctf challenge, deep sound windows tool can help in some cases. Sonic visualizer is for linux tool. 
 
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Keyboard cypher:

Hint: See on the keyboard for 2 minutes.

BUH~U>|:TIM{DYG~FKPHU~BP}KTYQ

As the hint says, need to watch on keyboard for 2 minutes so we can shift 2. 



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Someone took my bytes. Can you recover my password for me? In this challenge an encrypted code or text is given. In this case you can upload the file to cyber chef to see the tool can detect what encryption is used there. Then you can use xor or xor brute force algorithm to see any readable text can be recovered or not. Scroll from top to bottom. If found something like that starts with PK and password.txt and key is ff then it is your focusing point.


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hex to ascii:

72 74 63 70 7b 62 6f 62 5f 79 6f 75 5f 73 75 63 6b 5f 61 74 5f 62 65 69 6e 67 5f 65 6e 63 6f 75 72 61 67 69 6e 67 7d

It is base 16 or hexadecimal string convert from hexadecimal to ascii to get the flag

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Octal to ascii representation:

162 164 143 160 173 163 165 145 137 155 145 137 151 137 144 151 144 156 164 137 153 156 157 167 137 167 150 141 164 137 157 143 164 141 154 137 167 141 163 137 157 153 141 171 77 41 175 

this is given which is in octal representation

Convert this octal to ascii to get the flag.

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A1Z26 cypher: letter number cypher

A set of number is given 26 26 26 26 26 26 26 26 19 12 5 5 16 9 14 7 9 14 16 8 25 19 9 3 19

Here we can observe numbers range from 1-26 hence we can say it is A1Z26 cipher which can be decoded also as A=1, B=2, C=3, …, Z=26.

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If caesar cypher does not work then try atbash cipher. 
 
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beacon related to binary:
 
The question gives binary numbers 00110 01110 00100 00000 10011 00101 01110 01110 00011 00011 01110 01101 10011 10010 10011 00000 10001 10101 00100 . We can use these binary numbers to convert to text using Bacon cipher as given in question. Bacon cipher uses ‘a’ and ‘b’ which can be taken as a=0 and b=1 or vice versa.
 

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 Substitution cypher:
 
This is not final output as this can be decoded again using substitution ciphers which is abcdefghijklmnopqrstuvwxyz=mlkjihgfedcbazyxwvutsrqpon where from half of alphabets is reversed just like Porta Cipher but with an extra shift.
 
abcdefghijklmnopqrstuvwxyz
mlkjihgfedcbazyxwvutsrqpon 
 
zeziyvzyzi =  Hence we know z=n, e=i, z=n, i=e, y=o, v=r, z=n, y=o, z=n, i=e which gives flag as nineornone  
 
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Matrix algorithm ctf:
 
https://matrix.reshish.com/multiplication.php
 
 
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SKATS and Hangul language:
 
 
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RSA encryption decryption:
 
 
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space and * cypher:
 
replace all space with 1 and replace all * with 0 will give you a binary number. Decode it from cyber chef. 
 
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