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Redpwn 2020 Crypto - primimity

Primitity Description People claim that RSA with two 1024-bit primes is secure. But I trust no one. That's why I use three 1024-bit primes. I even created my own prime generator to be extra cautious! Files primimity.py primimity-public-key.txt Lets take a look at source primimity.py #!/usr/bin/env python3 from Crypto.Util.number imp...

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Redpwn 2020 Crypto - Itsy Bitsy

itsy-bitsy Description The itsy-bitsy spider climbed up the water spout... nc 2020.redpwnc.tf 31284 Files itsy-bitsy.py Lets quickly take a look at now the connection works nc 2020.redpwnc.tf 31284 Enter an integer i such that i > 0: 1 Enter an integer j such that j > i > 0: 2 Ciphertext: 0010001001011101111000001100000010000011...

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Redpwn 2020 Crypto - base646464

base646464 Description Encoding something multiple times makes it exponentially more secure! Files cipher.txt generate.js Lets take a look at generate.js, which reads const btoa = str => Buffer.from(str).toString('base64'); const fs = require("fs"); const flag = fs.readFileSync("flag.txt", "utf8").trim(); let ret = flag; for(let i...

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Redpwn 2020 Crypto - Alien Transmissions v2

Alien-transmissions-v2 Description The aliens are at it again! We've discovered that their communications are in base 512 and have transcribed them in base 10. However, it seems like they used XOR encryption twice with two different keys! We do have some information: * This alien language consists of words delimitated by the character repres...

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Redpwn 2020 Crypto - 4k-rsa

4k-rsa Description Only n00bz use 2048-bit RSA. True gamers use keys that are at least 4k bits long, no matter how many primes it takes... Files 4k-rsa-public-key.txt which contains a n, e, c triple Seems like there are a lot of primes in the factorization of n, since the factorization process is influenced directly by the size of prime fact...

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zh3r0 2020 Crypto - gboad maddy

gboad maddy Description You see this everyday if you use android. ?<³|⁰([{⁰|Pf¹&<=f{³&f"{P) Author : Finch the P stands for % as it causes build errors with jekyll, I substituted it Hint len(flag)=28 Someone pointed out after the ctf They we small accent symbols on gboard HMMMMMMMMMMMMMMMMMMMMMM Substituting the ...

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