tiny_nuke_new_decoder.py

def hexdump(src, length=16):
    FILTER = ''.join([(len(repr(chr(x))) == 3) and chr(x) or '.' for x in range(256)])
    lines = []
    for c in xrange(0, len(src), length):
        chars = src[c:c+length]
        hex = ' '.join(["%02x" % ord(x) for x in chars])
        printable = ''.join(["%s" % ((ord(x) <= 127 and FILTER[ord(x)]) or '.') for x in chars])
        lines.append("%04x  %-*s  %s\n" % (c, length*3, hex, printable))
    return ''.join(lines)
    
def decoder(data, key):
    decoded = ""
    for count, byte in enumerate(data):
        k = key[count % len(key)]
        temp = chr(ord(k) ^ ord(byte))
        decoded += temp
    return decoded

def extract(index):
    key = idc.get_bytes(index-6, 4)
    size = Word(index - 2)
    return key, size

def get_string(k,s,i):
    """type can be encoded-ascii, encoded-wide or non-encoded ascii"""
    temp_str = idc.get_bytes(i,s)
    if k == "\x00\x00\x00\x00":
        return temp_str.replace("\x00","")
    temp_data = idc.get_bytes(i,s)
    temp_str = decoder(temp_data, k)
    if "\x00" in temp_str[:4]:
        # decode wide char
        temp_data = idc.get_bytes(i,s*2)

        temp_str = decoder(temp_data, k).replace("\x00","")
    if all(c in string.printable for c in temp_str):
        return temp_str
    else:
        return None

def dec_here():
    i = here()
    k,s = extract(i)
    print get_string(k,s,i)
    idc.set_cmt(i, get_string(k,s,i),1)

def dec_ops():
    i = idc.get_operand_value(here(),1)
    k,s = extract(i)
    print get_string(k,s,i)
    idc.set_cmt(i, get_string(k,s,i), 1)
    
dec_here()