watermark_codec_pkg/watermark_codec/model_decoder.py

"""
Created on 2024/5/8
@author: <NAME>
@version: 1.0
@file: model_decoder.py
@brief 白盒水印解码器
"""
from typing import List

import torch
from torch import nn

from watermark_codec.tool.str_convertor import bin2string
from watermark_codec.tool.tensor_deal import load_tensor, flatten_parameters, get_prob


class ModelDecoder:
    def __init__(self, layers: List[nn.Conv2d], key_path: str = None, device='cuda'):
        # 判断传入的层是否全部为卷积层
        for layer in layers:
            if not isinstance(layer, nn.Conv2d):
                raise TypeError('传入参数不是卷积层')
        weights = [x.weight for x in layers]  # 获取所有卷积层权重
        self.w = flatten_parameters(weights)
        self.x_random = load_tensor(key_path, device)
        self.model = None

    def decode(self):
        prob = get_prob(self.x_random, self.w)
        decode = torch.where(prob > 0.5, 1, 0)
        code_string = ''.join([str(x) for x in decode.tolist()])
        code_string = bin2string(code_string)
        return code_string