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Flag 6: Mr Beep Boop Bot

Beep boop, my name is Mr Beep Boop Bot. I have a message for you, but I have only installed the minimal human language module. So I just used a language more native to me and I hope that you can read it.

Flag 7: Decrypt XOR or fail

Can you decrypt the following message that was encrypted using the XOR operation with a key that is 1 byte long?

Flag 8: Train to Crack Station

I was on the train the other day going to crack station when this person came up to me and told me the MD5 hash of their password. "Why would you do something like this?" I asked him, but they just told me that their name was John and said "if I was the chosen one I would be able to get his password".
Can you crack the hash below and get the password for John?
If you can't get to the crack station - just try searching on the web using the hash.

Flag 9: ECBrypted Image

On a late afternoon working hard as a NSA agent, you see an encrypted image sent between two suspected Kinder Surprise smugglers. After you inspect the communications further, you discover that the sender used AES encryption using the ECB mode to encrypt the image.
The original image was a PPM file and had a width and height of 1920 by 1080 pixels respectively. However, you were unable to figure out what was the key used to encrypt the image.
Can you still see the hidden message within the image?
Remember the lectures about ECB? But how do you view the image? A PPM file needs a header to be recognised. The specification for PPM is here
To add a header to the file you can create a file with the header (say, imgwithheader.ppm) and then do:
cat encrypted_image.bin >> imgwithheader.ppm
This will copy the contents of encrypted_image.bin and concatenate (add) it to the file imgwithheader.ppm.

Flag 10: Missing Letter

Help I have forgotten the end of my encryption key and I cannot decrypt my data!
I know I used AES-128 using CBC mode where the IV was 01020304050607080102030405060708 in hexadecimal and the key started off with harperssecretke. However. I still cannot decrypt my data below in hexadecimal format.
Can you guess the AES key and decrypt the data?