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90 points Hard

Hello!

I have just implemented a super-cool PRNG!

I've used every next generated by it number to XOR every next character in my super-secret message with.

Are you able to retrieve it?

Btw. Biggest possibly generated number by my PRNG is 255.

Psst. The retrieved message would be your flag!

As always, starting with: CTFlearn{...

I'm giving you the PRNG scheme with a brief description (description.png) and a "secretMessage.hex" file with every byte being the corresponding message char inside PRNG.zip file.

PRNG.zip
Flag
Cryptography ยท Wolfowy
93 solves
Rating 4.83
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Discussion

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Mujtab4x01

2 months ago

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done, had a good time understanding the LFSR and solving it manually, soon when i complete all the cryptography im gonna share the writeups on my website: reznov.is-great.org

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mildsunrise

1 year ago

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Mike_Root

3 years ago

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Wiki title. Once you fully understand the idea of the N mask, you can solve by trial and error with python string and xor skills. You should also be fluid in representing ascii strings in binary format to see what is happening with patterns...

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Ichild

3 years ago

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Wolfowy

3 years ago

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Great solution :)

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Rivit

3 years ago

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Very good challenge

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Wolfowy

3 years ago

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Thank you :)

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zharfanf

3 years ago

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remember format of the flag

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uyng

3 years ago

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The nice one! We have to do many steps by hand to find the seed key

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Wolfowy

3 years ago

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Thanks! It depends on an approach ;)

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