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Wireless healthcare systems are estimated to become a promising market within the next decade. Advances in wireless technology make it possible nowadays to replace wired solutions with more flexible wireless systems while providing similar levels of reliability. Such systems also make healthcare more accessible and efficient especially for patients such as the elderly who require long-term care but reside at home. Wireless healthcare monitoring includes the measurement and digitization of vital signs such as blood pressure or the electrocardiogram (ECG), transmitting packets securely over a wireless network to a remote station and delivering this medical information to medical professionals (Chou, 2012; Majoe, 2012; Varshney, 2006). One of the problems in such systems is where to store the acquired medical data. Regardless of whether the medical data are used for monitoring or diagnosis using, say, ECG, it first has to be recorded and stored. To provide an easy data exchange between patients, remote stations and medical professionals, this data can be stored securely in smart medical cards with a memory chip. Finally, using such portable media raises questions about data security. Because healthcare data contains highly sensitive and personal data, high levels of security must be applied for data protection and encryption.
In wireless medical monitoring systems, Bluetooth is often used to provide a wireless link between medical sensors and the monitoring system (Biel, 2001; Faundez-Zanuy, 2004; Jain, 2004; Saechia, 2005). Bluetooth operates in the unlicensed and globally standardized industrial, scientific, and medical (ISM) band, which uses a carrier frequency of 2.4 GHz (Nasri, 2009). Because of this and the fact that it offers high reliability, security and bandwidth at low costs, it is suitable for use in medical wireless devices worldwide
Healthcare systems that process and store signals should be capable of handling large amounts of data and different security requirements. Because of this reason, symmetric key cryptosystems are more suitable than public-key solutions to process this type of data effectively. The advanced encryption standard (AES) (FIPS, 2001) has become a de-facto-standard among symmetric key cryptosystems. It is used by all governments to protect data at different levels (e.g. when using AES-192 or AES-256) and is therefore suitable for storing sensitive healthcare data. AES has already been used in similar devices presented in (Fernandez, 2003; Jun-da, 2009).
Reconfigurable hardware, especially Field Programmable Gate Arrays (FPGAs), are widely used in image and signal processing applications, from simple low-resolution and low-bandwidth applications to very high-resolution and high-bandwidth applications (Ahmad,2010). Owing to its massive parallelism capabilities, multimillion gate counts and special low power packages, FPGA has attracted a great deal of research and development. FPGAs offer a nice trade-off in terms of cost, power, flexibility and design effort when compared with standard microprocessors, digital signal processor and application specific integrated circuit (ASIC).