HashRun安全团队wp

      #! /usr/bin/python3# by [email protected] at Thu May 24 18:44:15 CEST 2018
"""Pure Python 3 implementation of the ChaCha20 stream cipher.
It works with Python 3.5 (and probably also earler Python 3.x).
Based on https://gist.github.com/cathalgarvey/0ce7dbae2aa9e3984adcBased on Numpy implementation: https://gist.github.com/chiiph/6855750Based on http://cr.yp.to/chacha.html
More info about ChaCha20: https://en.wikipedia.org/wiki/Salsa20"""
import struct

def yield_chacha20_xor_stream(key, iv, position=0):  """Generate the xor stream with the ChaCha20 cipher."""  if not isinstance(position, int):    raise TypeError  if position & ~0xffffffff:    raise ValueError('Position is not uint32.')  if not isinstance(key, bytes):    raise TypeError  if not isinstance(iv, bytes):    raise TypeError  if len(key) != 32:    raise ValueError  if len(iv) != 8:    raise ValueError
  def rotate(v, c):    return ((v << c) & 0xffffffff) | v >> (32 - c)
  def quarter_round(x, a, b, c, d):    x[a] = (x[a] + x[b]) & 0xffffffff    x[d] = rotate(x[d] ^ x[a], 16)    x[c] = (x[c] + x[d]) & 0xffffffff    x[b] = rotate(x[b] ^ x[c], 12)    x[a] = (x[a] + x[b]) & 0xffffffff    x[d] = rotate(x[d] ^ x[a], 8)    x[c] = (x[c] + x[d]) & 0xffffffff    x[b] = rotate(x[b] ^ x[c], 7)
  ctx = [0] * 16  ctx[:4] = (1634760805, 857760878, 2036477234, 1797285236)  ctx[4 : 12] = struct.unpack('<8L', key)  ctx[12] = ctx[13] = position  ctx[14 : 16] = struct.unpack('<LL', iv)  while 1:    x = list(ctx)    for i in range(10):      quarter_round(x, 0, 4,  8, 12)      quarter_round(x, 1, 5,  9, 13)      quarter_round(x, 2, 6, 10, 14)      quarter_round(x, 3, 7, 11, 15)      quarter_round(x, 0, 5, 10, 15)      quarter_round(x, 1, 6, 11, 12)      quarter_round(x, 2, 7,  8, 13)      quarter_round(x, 3, 4,  9, 14)    for c in struct.pack('<16L', *(        (x[i] + ctx[i]) & 0xffffffff for i in range(16))):      yield c    ctx[12] = (ctx[12] + 1) & 0xffffffff    if ctx[12] == 0:      ctx[13] = (ctx[13] + 1) & 0xffffffff

def chacha20_encrypt(data, key, iv=None, position=0):  """Encrypt (or decrypt) with the ChaCha20 cipher."""  if not isinstance(data, bytes):    raise TypeError  iv=b'x03x01x02x04x03x05x01x02'  if isinstance(key, bytes):    if not key:      raise ValueError('Key is empty.')    if len(key) < 32:      # TODO(pts): Do key derivation with PBKDF2 or something similar.      key = (key * (32 // len(key) + 1))[:32]    if len(key) > 32:      raise ValueError('Key too long.')
  return bytes(a ^ b for a, b in      zip(data, yield_chacha20_xor_stream(key, iv, position)))plaintext =bytes([0x9F,0x29,0x32,0x8A,0x0C3,0x70,0x0BC,0x0EA,0x20,0x40,0x0F1,0x17,0x69,0x0E8,0x0FD,0x40,0x3,0x0E6,0x0A3,0x97,0x0B7,0x1E,0x0D3,0x0BF,0x24,0x83,0x32,0x0AB,0x79,0x28,0x25,0x37])key = bytes([0xC,0x17,0x22,0x17,0x2B,0x36,0x4C,0x2D,0x21,0x36,0x41,0x17,0x2D,0x17,0x41,0x20,0x0C,0x36,0x17,0x41,0x56,0x19,0x2D,0x4B,0x4A,0x17,0x40,0x55,0x18,0x2E,0x4C,0x22])flag=bytearray(chacha20_encrypt(plaintext,key))for i in range(0,32,2):    l=flag[i]    flag[i]=flag[i+1]    flag[i+1]=lprint(flag)