An Integration Design of Compression and Encryption for Biomedical Signals
A telemedicine system using communication and information technology to deliver biomedical signals for long-distance medical services has become reality. In either the urgent treatment or ordinary health care, it is necessary to compress the signals for the efficient use of bandwidth. In addition, when compressed biomedical signals or data are delivered over a public channel such as the Internet, their privacy and security would also be an important issue.
The SPIHT (set partitioning in hierarchical trees) is shown recently as an excellent biomedical signal compression method, and the AES (advanced encryption standard) is the state-of-the-art data encryption standard. Data compression and encryption are normally treated as two separate and independent research areas or building blocks in a communication system. However, they are jointly considered in this paper, where we propose a partially encrypting scheme combining SPIHT and AES. In this scheme, compressed SPIHT bit streams are identified based on their importance to signal quality. Then AES is used to encrypt only the important part that can be defined and chosen by a user. The proposed scheme has, therefore, the advantage of encryption scalability. The experiments on electrocardiogram signals and medical images show that the proposed scheme can have significant security protection even only a small portion of compressed data is encrypted, resulting in the considerable saving of processing time.