Wow, this one was really fun. Not just binwalk or steghide, but truly an upper-medium difficulty level! Really liked this challenge, thank you! Hint: when it comes to length, don't overthink it but be careful with it!

Glad you liked it, I enjoyed creating it.

i dont understand with -iv and -K, where i find them, i need them to solve, i get the clue : -iv SOF0 and -K SOS, what meaning that!!, help meee @kcbowhunter

You need to google jpeg file format, SOF0 is a certain block inside the jpeg image, SOS is 'start of scan'

I've found -sof0 and -iv in after using dump image on https://cyber.meme.tips/jpdump/#, then what should I input in -iv and -K? I've found the flag.enc file, so that the flag.enc file can be decrpyt? my problem is just because -iv and -K, help mee @kcbowhunter

you put the bytes in i.e. BAADF00D you need to research how many bytes are needed

can someone explain to me why they count this as 32 bytes when its 64 when i use a counter? 000c03010002110311003f00f9766bfc44beda8f3f5c031b92cb0e92d6bdc952

each byte is represented by two characters, so the string is 64 characters and it represents 32 bytes. 0xff or ff is the decimal value 255 which is one byte with all 8 bits set to 1, i.e. 11111111

Great challenge! Learnt more about AES-256. Thank you kcbowhunter for your help!

Glad you liked it, this was one of my favorite challenges to create.

Congrats, I like this challenge... it does require some knowledge of jpeg internal file format but that can be easily found via google

i hate this f*ckin "C". i think it is part of the aes cipher that make me stuck about few hours for getting bad decrypt. I suddenly noticed because of this web https://cyber.meme.tips/jpdump/#. btw thanks kcbowhunter, i learning a lot from this challenge

I don't really get why the C be there. Anyone could explain?

Was interesting, learned a lot, this is kcbowhunter signature. Good job!

Thanks!

I've found -sof0 and -iv in after using dump image on https://cyber.meme.tips/jpdump/#, then what should I input in -iv and -K? I've found the flag.enc file, so that the flag.enc file can be decrpyt? my problem is just because -iv and -K, help mee @kcbowhunter

you put in the byes, ie. BAADF00D, you need to research how many bytes are required

learnt more about aes256, nice challenge!

Thanks to kcbowhunter for your help.

Very nice challenge! Learned alot about encryption and jpg compression.

Glad you liked it, this was one of my favorites to create.