Pseudo Random Encryption?

[Tech2025]

Hi, I am trying to decrypt something in a .txt file as a challenge from a friend, the file contains:

pÿd“ÙÃÊÌßéh'rv‹"^÷ù O˜w؉D•ÍúúYíY’ ∞¶iÀªÆzI¥r=«Å∑F¸¡„;≥ûü¸ã7∂.ˆ– ã<¿µD~’ÅsG›îwA_4Gå#›¥’6ª˝_ÎaÍÑjù]ÚU3Y{äF-Ê#i 33(›öR `?™|¸ ®flîè+zÂ√œ/fiãìR˛˙˚∂ZëìƺΩÒ†»˘∂®∑‘¬z vóR◊r∂Øûp)E ·°vÅQ’»<Ø^ÃH‘xïÄ=∂Ë\⁄oYh◊¥h$f)

I think it is Pseudo Random encryption? Can someone give hints on how to decrypt this?

 

[jedishrfu]

I think this is related to the cicada3301 mystery:

https://www.fastcompany.com/3025785/meet-the-man-who-solved-the-mysterious-cicada-3301-puzzle

In your case, try converting it to hex or decimal to see if there's a discernable pattern.

 

[Tech2025]

I think this is related to the cicada3301 mystery:

https://www.fastcompany.com/3025785/meet-the-man-who-solved-the-mysterious-cicada-3301-puzzle

In your case, try converting it to hex or decimal to see if there's a discernable pattern.

Interesting, Will try that, Do you know any good Encryption/Cipher analyzer software for Windows?

 

[jedishrfu]

No I don't. People try the tricks of the trade to solve these things. One thing is that the message must be long enough relative to the encoding scheme.

If you have access to Linux or MacOSX or an editor that can display HEX you could use that to look at the digital representation.

 

[jedishrfu]

Here's another Cicada 2018 video:

 

[anorlunda]

One thing is that the message must be long enough relative to the encoding scheme.

That's very true, and that text is very short. My guess is that it is a trivial trick, much simpler than pseudo random encryption.

For example, the text looks like the 16 bit UNICODE, what happens if you display the same binary sequence as 8 bit ASCII?