Block cipher challenge

Level: CTR mode

Sorry, you're not an admin (need is_admin: true)



Ciphertext (hexencoded), for easy copy-paste

3f40c77b850fdafc149912aa12f1058f594668214131cee4f36849aa0e902bc0c820e2d60d70475343ac28c619b5ee64a8ef31f2c3dd4142444ad54c1e7f9d1c

Ciphertext (hexencoded):

3f40c77b850fdafc149912aa12f1058f 594668214131cee4f36849aa0e902bc0 c820e2d60d70475343ac28c619b5ee64 a8ef31f2c3dd4142444ad54c1e7f9d1c

Plaintext (hexencoded):

3f40c77b850fdafc149912aa12f1058f 7b22757365726e616d65223a20226775 657374222c202269735f677565737422 3a20747275657d090909090909090909

Plaintext:

?@\xc7{\x85\x0f\xda\xfc\x14\x99\x12\xaa\x12\xf1\x05\x8f {"username": "gu est", "is_guest" : true}\t\t\t\t\t\t\t\t\t

Final plaintext

{"username": "guest", "is_guest": true}