Various methods have been proposed to secure access to sensitive information over time, such as the many cryptographic methods in use to facilitate secure communications on the internet. But other methods like steganography have been overlooked which may be more suitable in cases where the act of transmission of sensitive information itself should remain a secret. Multiple techniques that are commonly discussed for such scenarios suffer from low capacity and high distortion in the output signal. This research introduces a novel steganographic approach for concealing a confidential portable document format (PDF) document within a host image by employing the Hybrid Firefly algorithm (HFA) proposed to select the pixel arrangement. This algorithm combines two widely used optimization algorithms to improve their performance. The suggested methodology utilizes the HFA algorithm to conduct a search for optimal pixel placements in the spatial domain. The purpose of this search is to accomplish two main goals: increasing the host image's capacity and reducing distortion. Moreover, the proposed approach intends to reduce the time required for the embedding procedure. The findings indicate a decrease in image distortion and an accelerated rate of convergence in the search process. The resultant embeddings exhibit robustness against steganalytic assaults, hence rendering the identification of the embedded data a formidable undertaking.

通过使用混合萤火虫算法（HFA）选择像素排列，本研究介绍了一种新颖的隐写方法，可以将机密的便携文档格式（PDF）文件隐藏在主机图像中。该方法通过在空间域中寻找最佳像素放置来增加主机图像的容量和降低失真，并且减少了嵌入过程所需的时间。结果揭示了图像失真的减少以及搜索过程中的收敛速度加快，从而使得识别嵌入数据成为一项艰巨的任务。

基于混合萤火虫算法的图像安全信息嵌入