Decode KeyStrokes from USB-PCAP [For CTF]

exploit.py

# tshark -r usb.pcapng -T fields -e usb.capdata | grep -E "^.{23}$" | grep -v 00:00:00:00:00:00:00:00 > data.txt

usb_codes = {
    0x04:"aA", 0x05:"bB", 0x06:"cC", 0x07:"dD", 0x08:"eE", 0x09:"fF",
    0x0A:"gG", 0x0B:"hH", 0x0C:"iI", 0x0D:"jJ", 0x0E:"kK", 0x0F:"lL",
    0x10:"mM", 0x11:"nN", 0x12:"oO", 0x13:"pP", 0x14:"qQ", 0x15:"rR",
    0x16:"sS", 0x17:"tT", 0x18:"uU", 0x19:"vV", 0x1A:"wW", 0x1B:"xX",
    0x1C:"yY", 0x1D:"zZ", 0x1E:"1!", 0x1F:"2@", 0x20:"3#", 0x21:"4$",
    0x22:"5%", 0x23:"6^", 0x24:"7&", 0x25:"8*", 0x26:"9(", 0x27:"0)",
    0x2C:"  ", 0x2D:"-_", 0x2E:"=+", 0x2F:"[{", 0x30:"]}",  0x32:"#~",
    0x33:";:", 0x34:"'\"",  0x36:",<",  0x37:".>"
    }

lines = ["","","","",""]

pos = 0

for x in open("data.txt","r").readlines():
    code = int(x[6:8],16)

    if code == 0:
        continue
    # newline or down arrow - move down
    if code == 0x51 or code == 0x28:
        pos += 1
        continue
    # up arrow - move up
    if code == 0x52:
        pos -= 1
        continue

    # select the character based on the Shift key
    if int(x[0:2],16) == 2:
        lines[pos] += usb_codes[code][1]
    else:
        lines[pos] += usb_codes[code][0]


for x in lines:
    print x