code: func obfuscateBloom(bloom []byte) {
  	const half = entropySize / 2
  	for i := 0; i < half; i++ {
  		x := int(entropy[i])
  		if entropy[half+i] < 128 {
  			x += 256
  		}
  
  		bloom[x/8] = 1 << uint(x%8) // set the bit number X
  	}
  }
docs: // obfuscateBloom adds 16 random bits to the bloom
  // filter, in order to obfuscate the containing topics.
  // it does so deterministically within every session.
  // despite additional bits, it will match on average
  // 32000 times less messages than full node's bloom filter.