It is wireshark capture file. We can see the log of keyboard inputs. So extract and merge them.
urb = {
'04':'A', '05':'B', '06':'C', '07':'D',
'08':'E', '09':'F', '0a':'G', '0b':'H',
'0c':'I', '0d':'J', '0e':'K', '0f':'L',
'10':'M', '11':'N', '12':'O', '13':'P',
'14':'Q', '15':'R', '16':'S', '17':'T',
'18':'U', '19':'V', '1a':'W', '1b':'X',
'1c':'Y', '1d':'Z', '1e':'1', '1f':'2',
'20':'3', '21':'4', '22':'5', '23':'6',
'24':'7', '25':'8', '26':'9', '27':'0',
'28':'\n', '29':'[ESC]','2a':'[del]','2a':'[tab]',
'2c':' ', '2d':'_', '2e':'=', '2f':'{',
'30':'}', '33':';', '34':'"', '3a':'[F1]',
'4c':'[DELETE]', '4f':'[RIGHT]', '50':'[LEFT]'
,'51':'[DOWN]', '52':'[UP]'
}
a = open("output.txt").read().split('\n')[:-1]
r = ''
for i in range(len(a)):
print(a[i])
b = [a[i][j:j+2] for j in range(0, len(a[i]), 2)]
print(b)
if b[2] == '00':
continue
if b[0] == '00':
r += urb[b[2]].lower()
else:
r += urb[b[2]]
print(r)
flag is: irisctf{this_keylogger_is_too_hard_to_use}