Hello World的魔幻打印

今天遇到了个很好玩的话题，怎么模（魔）糊（幻）打印Hello World。和平常第一次接触编程语言的Hello World不一样，平常一行就能完成的功能这里实现的能够异常复杂，并且生成了一堆看似乱码的字符，结果用python解析运行却能得到和Hello World一样的结果，原理我到现在还没完全搞明白，先做个记录后面慢慢理解吧。

先看要求：
Task:

Create an obfuscated program that prints Hello World! (exactly like that). Your program may not have any strings in it.

Rules:

You can use any programming language you like.
Make it as obfuscated as possible
This is a popularity-contest, so the answer with the most upvotes wins.

如下答案高票得选：

(lambda _, __, ___, ____, _____, ______, _______, ________: getattr(__import__(True.__class__.__name__[_] + [].__class__.__name__[__]), ().__class__.__eq__.__class__.__name__[:__] + ().__iter__().__class__.__name__[_____:________])(_, (lambda _, __, ___: _(_, __, ___))(lambda _, __, ___: chr(___ % __) + _(_, __, ___ // __) if ___ else (lambda: _).func_code.co_lnotab, _ << ________, (((_____ << ____) + _) << ((___ << _____) - ___)) + (((((___ << __) - _) << ___) + _) << ((_____ << ____) + (_ << _))) + (((_______ << __) - _) << (((((_ << ___) + _)) << ___) + (_ << _))) + (((_______ << ___) + _) << ((_ << ______) + _)) + (((_______ << ____) - _) << ((_______ << ___))) + (((_ << ____) - _) << ((((___ << __) + _) << __) - _)) - (_______ << ((((___ << __) - _) << __) + _)) + (_______ << (((((_ << ___) + _)) << __))) - ((((((_ << ___) + _)) << __) + _) << ((((___ << __) + _) << _))) + (((_______ << __) - _) << (((((_ << ___) + _)) << _))) + (((___ << ___) + _) << ((_____ << _))) + (_____ << ______) + (_ << ___))))(*(lambda _, __, ___: _(_, __, ___))((lambda _, __, ___: [__(___[(lambda: _).func_code.co_nlocals])] + _(_, __, ___[(lambda _: _).func_code.co_nlocals:]) if ___ else []), lambda _: _.func_code.co_argcount, (lambda _: _, lambda _, __: _, lambda _, __, ___: _, lambda _, __, ___, ____: _, lambda _, __, ___, ____, _____: _, lambda _, __, ___, ____, _____, ______: _, lambda _, __, ___, ____, _____, ______, _______: _, lambda _, __, ___, ____, _____, ______, _______, ________: _)))

第一印象，什么鬼？？第二眼还是看不懂。
来看看作者怎么解释的。

Here is a more readable version: http://codepad.org/UzSmoxF2

Notes:
One line, single expression (i.e. no print statement).
No strings, no ints; only functions, attribute access, lists, tuples, basic math, one True, and one star-args.
Minimal builtin usage (__import__, getattr, and chr once each).
The payload can be changed easily. Here is the program I wrote to generate it.
Edit: I wrote a fairly substantial explanation of how this works on my blog.

编写generate.py脚本通过对输入字符串加密：

# How to use?
# python generate.py "the str needed to be encry"
#

from math import ceil, log
import sys

def encode_string(s):
    bytes = [ord(c) for c in s]
    num = sum(bytes[i] * 256 ** i for i in range(len(bytes)))
    return reduce(num, 0)

def reduce(num, depth):
    def _encode(num, depth):
        if num == 0:
            return "_ - _"
        if num in range(9):
            return "_" * num
        return "(" + reduce(num, depth + 1) + ")"
    result = ""
    while num:
        best_base = best_shift = 0
        best = num
        span = int(ceil(log(abs(num), 1.5))) + (16 >> depth)
        for base in range(span):
            for shift in range(span):
                diff = abs(num) - (base << shift)
                if abs(diff) < abs(best):
                    best = diff
                    best_base = base
                    best_shift = shift
        if result:
            result += " + " if num > 0 else " - "
        elif num < 0:
            best_base = -best_base
        if best_shift == 0:
            result += _encode(best_base, depth)
        else:
            result += "(%s << %s)" % (_encode(best_base, depth),
                                      _encode(best_shift, depth))
        num = best if num > 0 else -best
    return result

# print(len(sys.argv))
# print(' '.join(sys.argv[1:]))
result = encode_string(str(' '.join(sys.argv[1:]))+"\n")
print("Encrypted Text: ")
print(result)

Run tese case:

(base) huang@mlp:~/taichi/intel$ python generate.py huang zhiyuan
Encrypted Text:
(((_______ << ___) - _) << ((___ << _____) + _)) + (((___ << _____) + _) << ((((___ << __) - _) << ___))) + (((((_ << ____) - _) << ___) - ___) << ((_____ << ____))) + (((((_ << ____) - _) << ___) + _) << (((((_ << ___) + _)) << ___))) + (((((___ << __) + _) << ___) + _) << ((_ << ______))) + ((((___ << __) + _)) << ((((_ << ____) - _) << __) - _)) + (((((_ << ____) - _) << __) + _) << ((___ << ____) + _)) + (((_ << ______) + _) << ((_____ << ___) - _)) - (((___ << ____) + _) << ((_ << _____) - _)) - ((((((_ << ___) + _)) << __) - _) << ((___ << ___) - _)) - (((_ << _____) - _) << ((_ << ____))) + (((_______ << __) + _) << ((_____ << _))) + ((((___ << __) - _)) << _____) + (_ << ___)

利用上面生成的加密字符填充运行脚本run.py：

huang@mlp:~/taichi/intel$ cat run.py

(lambda _, __, ___, ____, _____, ______, _______, ________:
    getattr(
        __import__(True.__class__.__name__[_] + [].__class__.__name__[__]),
        ().__class__.__eq__.__class__.__name__[:__] +
        ().__iter__().__class__.__name__[_____:________]
    )(
        _, (lambda _, __, ___: _(_, __, ___))(
            lambda _, __, ___:
                chr(___ % __) + _(_, __, ___ // __) if ___ else
                (lambda: _).func_code.co_lnotab,
            _ << ________,

            ## fill the encrypted text here
            (((_____ << _____) + _______) << ((___ << _____) + (_ << __))) - ((((___ << __) + _)) << ((___ << _____) - ___)) + (((___ << _____) - ___) << ((_____ << ____) + (_ << _))) + (((___ << ____) - _) << (((((_ << ___) + _)) << ___) + ___)) + (((((___ << __) - _) << __) + _) << ((((_ << ____) + _) << __) - _)) + (((((___ << __) - _) << __) + _) << ((((_ << ____) - _) << __) - _)) + (((((_ << ____) - _) << __) + _) << ((___ << ____) + _)) + (((_ << ______) + _) << ((_____ << ___) - _)) - (((___ << ____) + _) << ((_ << _____) - _)) - ((((((_ << ___) + _)) << __) - _) << ((___ << ___) - _)) - (((_ << _____) - _) << ((_ << ____))) + (((_______ << __) + _) << ((_____ << _))) + ((((___ << __) - _)) << _____) + (_ << ___)

        )
    )
)(
    *(lambda _, __, ___: _(_, __, ___))(
        (lambda _, __, ___:
            [__(___[(lambda: _).func_code.co_nlocals])] +
            _(_, __, ___[(lambda _: _).func_code.co_nlocals:]) if ___ else []
        ),
        lambda _: _.func_code.co_argcount,
        (
            lambda _: _,
            lambda _, __: _,
            lambda _, __, ___: _,
            lambda _, __, ___, ____: _,
            lambda _, __, ___, ____, _____: _,
            lambda _, __, ___, ____, _____, ______: _,
            lambda _, __, ___, ____, _____, ______, _______: _,
            lambda _, __, ___, ____, _____, ______, _______, ________: _
        )
    )
)

验（zhuang）证（bi）结（shi）果（ke）：

(base) huang@mlp:~/taichi/intel$ python2 run.py
huang zhiyuan

版本目前来看只支持python2，否则会报error,从python2到python3有些built-in函数attribute命名规则发生了改变。

The function attributes named func_X have been renamed to use the __X__ form, freeing up these names in the function attribute namespace for user-defined attributes. To wit, func_closure, func_code, func_defaults, func_dict, func_doc, func_globals, func_name were renamed to __closure__, __code__, __defaults__, __dict__, __doc__, __globals__, __name__, respectively.

(base) huang@mlp:~/taichi/intel$ python run.py
Traceback (most recent call last):
  File "run.py", line 32, in <module>
    lambda _, __, ___, ____, _____, ______, _______, ________: _
  File "run.py", line 18, in <lambda>
    *(lambda _, __, ___: _(_, __, ___))(
  File "run.py", line 21, in <lambda>
    _(_, __, ___[(lambda _: _).func_code.co_nlocals:]) if ___ else []
AttributeError: 'function' object has no attribute 'func_code'

参考链接：
https://codegolf.stackexchange.com/questions/22533/weirdest-obfuscated-hello-world
https://benkurtovic.com/2014/06/01/obfuscating-hello-world.html
http://codepad.org/UzSmoxF2
http://codepad.org/oVuFVcB5