Cryptographic Algorithms Research Articles

Parallel lightweight Block Cipher algorithm for Multicore CPUs

أصبحت حماية البيانات واحدة من أهم القضايا على الرغم من التقدم الكبير في الاتصالات والتكنولوجيا. لكي ترسل التكنولوجيا المستندة إلى الويب البيانات بسرعة وأمان ، يجب تشفير البيانات. التشفير هو عملية تحويل النص العادي إلى نص مشفر ، لا يستطيع الأشرار قراءته أو تغييره. تتطلب كل من إجراءات تحليل التشفير وفك التشفير قدرًا كبيرًا من الوقت من أجل الحفاظ على المستوى المطلوب من الأمان. ومع ذلك ، طور عدد من الباحثين نهج التشفير بالتوازي من أجل تقليل مقدار الوقت اللازم لإنهاء إجراءات التشفير وفك التشفير. أنتج التحقيق في هذه القضية عددًا من الحلول القابلة للتطبيق. تمكن الباحثون من تحقيق مستويات أداء محسّنة في تقنية التشفير باستخدام التوازي لزيادة الإنتاجية وتعزيز كفاءة طرق التشفير. لتحقيق أداء عالٍ ، تم تقديم خوارزميات تشفير البقعة خفيفة الوزن وتنفيذها على منصات وحدة المعالجة المركزية مع تحسينات مختلفة. وبالتالي ، في هذا العمل ، تم اقتراح مخطط تشفير خفيف الوزن يستخدم جولة واحدة فقط من تقنية تشفير الكتلة التي يتم تطبيقها بالتوازي على معالج متعدد النواة. تستخدم خوارزمية تشفير الرسائل المقترحة كتلتين فرعيتين من 128 بت من الرسائل العادية ومربع الاستبدال و splitmix64 PRNG لتشفير الرسالة العادية والحصول على كتلتين فرعيتين مشفرتين ، مما يجعلها تقنية سريعة لتشفير وفك تشفير كتل الرسائل. بالمقارنة مع الطريقة الحالية. وفقًا لنتائج الأداء ، فإنه قادر على الوصول إلى إنتاجية عالية للبيانات مقارنة ببعض الأساليب خفيفة الوزن الموجودة بالفعل ، مع معدل نقل أعلى من 25 كيكابت في الثانية على وحدة المعالجة المركزية Intel Core i7. تتفوق طريقة التشفير المقترحة على طريقة البقع المتوازية بمعدل 14.10 مرة أسرع عند تنفيذها على وحدة معالجة مركزية متعددة النواة. متوسط التسريع مقارنة بالنسخة التسلسلية للخوارزمية المقترحة والتنفيذ المتوازي لها هو 4.70. أيضًا ، توفر طريقة التشفير المقترحة قدرًا كبيرًا من العشوائية وتجتاز الاختبارات الإحصائية لـ PractRand. وبالتالي ، فإن الطريقة المقترحة هي منافس قوي للتنفيذ عالي الأمان على المعالجات متعددة النواة.

Post-quantum XML and SAML Single Sign-On

Extensible Markup Language (XML) is one of the most popular serialization languages. Since many security protocols are built using XML, it also provides cryptographic functionality. A central framework in this area is the Security Assertion Markup Language (SAML). This standard is one of the most widely used options for implementing Single Sign-On (SSO), which allows users to authenticate to different service providers using the credentials from a single identity provider. Like all other security protocols currently in use, the security and privacy of XML-based frameworks such as SAML is threatened by the development of increasingly powerful quantum computers. In fact, future attackers with access to scalable quantum computers will be able to break the currently used cryptographic building blocks and thus undermine the security of the SAML SSO to illegally access sensitive private information. Post-quantum cryptography algorithms have been developed to protect against such quantum attackers. While many security protocols have been migrated into the quantum age by using post-quantum cryptography, no such solutions for XML and the security protocols based on it have been developed, let alone tested. We make the following contributions to fill this gap. We have designed post-quantum solutions for the cryptographic building blocks in XML and integrated them into the SAML SSO protocol. We implemented our solutions in the OpenSAML, Apache Santuario, and BouncyCastle libraries and extensively tested their performance for various post-quantum instantiations. As a result, we have created a comprehensive and solid foundation for post-quantum XML and post-quantum SAML SSO migration.

Enhance Key Stage Generation for Developing Kasumi Encryption Algorithm

Today, data security is a critical component of the efficient performance of every organization's diverse requirement, one of the important requirements is to provide a secure connection for data transmission in organization's networks. Cryptography algorithms are used to protect transmitted data from unauthorized access. Every day, a great deal of research is being done. The process of encrypting data is currently under development. Therefore, a substantial technological or research effort is still required. Cellular networks and secure communication. This proposal calls for the development of a new encryption system based on Using random keys in all the rounds. That’s mean we generated random keys as 128 bits for each round and save it in an array with size (8×8) because we have 8 rounds and each key divided into 8 sub keys as 16 bits for each to use in encryption and decryption. The developed random keys and traditional algorithm keys were tested with statistical tests of NIST, which made up a comparison and conclusion that the developed keys have a higher randomness specially in linear complexity, Frequency within block and random excursion tests, which leads to a better quality of encryption. Then we could test the cipher text with frequency within block test that was evaluated by (0.49590998713105255) and the approximate entropy test that was evaluated by (0.4922198616875501) for each cipher text which resulted from standard and modified Kasumi algorithm that’s means we can conclude that our modified Kasumi algorithm achieved more secure data in its resulted cipher text.

Enhance Key Stage Generation for Developing Kasumi Encryption Algorithm

Today, data security is a critical component of the efficient performance of every organization's diverse requirement, one of the important requirements is to provide a secure connection for data transmission in organization's networks. Cryptography algorithms are used to protect transmitted data from unauthorized access. Every day, a great deal of research is being done. The process of encrypting data is currently under development. Therefore, a substantial technological or research effort is still required. Cellular networks and secure communication. This proposal calls for the development of a new encryption system based on Using random keys in all the rounds. That’s mean we generated random keys as 128 bits for each round and save it in an array with size (8×8) because we have 8 rounds and each key divided into 8 sub keys as 16 bits for each to use in encryption and decryption. The developed random keys and traditional algorithm keys were tested with statistical tests of NIST, which made up a comparison and conclusion that the developed keys have a higher randomness specially in linear complexity, Frequency within block and random excursion tests, which leads to a better quality of encryption. Then we could test the cipher text with frequency within block test that was evaluated by (0.49590998713105255) and the approximate entropy test that was evaluated by (0.4922198616875501) for each cipher text which resulted from standard and modified Kasumi algorithm that’s means we can conclude that our modified Kasumi algorithm achieved more secure data in its resulted cipher text.

The main ways to improve the effectiveness of electronic document management protection

Information resources and information systems are among the main protected elements in all spheres of life of modern enterprises [11-15]. Today, the means of negative information impact on these elements are actively developing, the counteraction of which requires extensive diverse research and development of relevant concepts, programs for organizing specific work in the field of creating tools, methods and techniques for ensuring information security. Illegal distribution of digital documents by authorized but unscrupulous users is a growing threat to the confidentiality of organizations, which a document management system using only encryption methods cannot fully cope with. This problem occurs together with access to a digital document by unauthorized users. In this article, as a countermeasure to protect digital documents from these two threats, a new approach is proposed that carefully combines encryption and fingerprinting methods at certain stages of the digital document lifecycle. Within this scenario, a full analysis was carried out, in which the main constituent elements, their interaction, data flow and the provision of security services were identified. This protection system guarantees a sufficient level of security, since it uses standard cryptographic algorithms and recommended key sizes. The purpose of this approach is to provide information security services such as confidentiality, integrity, authentication, non-repudiation and user tracking, thereby protecting digital documents throughout their entire life cycle.

Hardware Acceleration for High-Volume Operations of CRYSTALS-Kyber and CRYSTALS-Dilithium

Many high-demand digital services need to perform several cryptographic operations, such as key exchange or security credentialing, in a concise amount of time. In turn, the security of some of these cryptographic schemes is threatened by advances in quantum computing, as quantum computer could break their security in the near future. Post-quantum cryptography (PQC) is an emerging field that studies cryptographic algorithms that resist such attacks. The National Institute of Standards and Technology (NIST) has selected the CRYSTALS-Kyber Key Encapsulation Mechanism and the CRYSTALS-Dilithium Digital Signature algorithm as primary PQC standards. In this article, we present field-programmable gate array (FPGA)-based hardware accelerators for high-volume operations of both schemes. We apply high-level synthesis (HLS) for hardware optimization, leveraging a batch processing approach to maximize the memory throughput and applying custom HLS logic to specific algorithmic components. Using reconfigurable FPGAs, we show that our hardware accelerators achieve speedups between 3 \(\times\) and 9 \(\times\) over software baseline implementations, even over ones leveraging CPU vector architectures. Furthermore, the methods used in this study can also be extended to the new CRYSTALS-based NIST FIPS drafts, ML-KEM and ML-DSA, with similar acceleration results.

Integrating Quantum Computing Into Blockchain: Strategies for Overcoming Scalability and Security Challenges

, , , , & Department of Computer Science and Pure & Applied Physics Ladoke Akintola University of Technology Ogbomoso, Oyo State, Nigeria E-mails: golamiji@lautech.edu.ng, soolabiyisi@lautech.edu.ng, woismaila@lautech.edu.ng, ofalade28@pgschool.lautech.edu.ng, ljmkadeola@gmail.com ABSTRACT The rapid progression of quantum computing has created new opportunities for advancing blockchain technology, particularly in addressing its two primary challenges which are scalability and security. As blockchain adoption grows, traditional consensus mechanisms reveal significant inefficiencies, causing transaction bottlenecks and increased latency. Additionally, the advent of quantum computing poses a significant threat to the classical cryptographic algorithms foundational to blockchain security. This research introduces an innovative approach that harnesses quantum computing to address these dual challenges. To enhance scalability, this research proposes integrating Grover's algorithm and Post Quantum encryption alogrithms to optimize transaction selection and validation, significantly reducing time complexity compared to classical methods. On the security front, the research introduces post-quantum cryptographic techniques to strengthen blockchain networks against quantum adversaries. Simulations conducted on IBM Qiskit Quantum Computer Simulator demonstrate that the proposed framework achieves superior efficiency, cost-effectiveness, and faster transaction processing with Grover's algorithm and Post Quantum encryption alogrithms compared to the current classical systems. These improvements highlight the potential benefits of utilizing quantum computing to deploy quantum-enhanced blockchain. Keywords: Quantum, Computing, IBM, Qiskit, blockchain, Post-Quantum, Encryption CISDI Journal Reference Format Gabriel, O., Olabiyisi, S.O., Ismaila, W.O., Falade, O.A., & Alawode O. (2024): Integrating Quantum Computing Into Blockchain: Strategies for Overcoming Scalability and Security Challenges. Computing, Information Systems, Development Informatics & Allied Research Journal. Vol 15 No 3, Pp 15-28. dx.doi.org/10.22624/AIMS/CISDI/V15N3P2 Available online at www.isteams.net/cisdijournal

Development of Hill Cipher Method For Encryption And Decryption of Drug Prescriptions to Improve Data Security

A prescription is a written request from a doctor to a pharmacist, as not everyone can know the dosage or type of a particular drug, especially patients who need a prescription for the drug must be kept secret. Rapid technological advances can have an impact on all sectors, both private and government, including the medical field. One of the medical services that utilizes IT is to send prescription messages electronically to pharmacists in response to doctors' requests. The many misuse of prescription drugs by irresponsible people and misreading prescription drugs by pharmacists can be fatal for patients, so a solution is needed to overcome these problems. The purpose of this study is to create an encrypted electronic recipe application using the Hill Cipher method. This research method generally starts from data collection, data analysis and encryption model development. Applications designed with the Hill Cipher Algorithm are developed with modified algorithm keys using postal code patterns as the matrix keys, this aims to achieve the maximum level of security. The results of the system functionality test using the black box method obtained normal results for all system test scenarios. Validity testing yields valid results. The final test, through questionnaire testing, obtained a good level of system feasibility, namely an average level of Service of 83%, Features of 78% and Performance of 81%. Overall, the system has given a good performance score as the accuracy of the system is above 70%.

Quantum Computing and the Implications on Online Security

Over the past year, quantum computing has seen many advancements due to contributions from UC Berkeley in collaboration with IBM’s laboratories. Although these breakthroughs seem promising, they introduce new security concerns regarding the potential for quantum attacks to become a major threat in future data breaches. This research investigates the efficiency of many quantum cryptographic techniques. These algorithms include Quantum Key Distribution (QKD), Lattice-Based Cryptography, and Multivariate Cryptography. Utilizing IBM’s Qiskit Python extensions, we were able to test these methods against quantum attack algorithms, including Shor's Algorithm, Grover's Algorithm, and the BB84 protocol. Our results indicate that, although current cryptographic methods provide some level of defense against quantum attacks, there needs to be advancements to protect our digital infrastructure for the future. This study puts emphasis on the need for more development in cryptographic algorithms to ensure proper security in the era of quantum computing.

Evaluating cryptographic vulnerabilities created by quantum computing in industrial control systems

AbstractQuantum computing is expected to eventually be able to break the public‐key cryptography algorithms currently used throughout information technology (IT) infrastructure, undermining foundational tools used to maintain information security across the country's critical infrastructure. As these systems converge, the security posture of operational technology (OT) systems has to adapt to a new threat landscape and adopt some of the same security controls as those used in enterprise IT, especially cryptographic controls that rely on public‐key cryptography, which are ubiquitous in enterprise IT systems. Operators and manufacturers of industrial control systems (ICSs) and OT systems will need to understand and address the unique ways in which these systems will be vulnerable to adversaries equipped with quantum computers. We assessed quantum computing–facilitated cryptographic vulnerabilities in ICSs and OT systems to identify the issues in need of the most‐urgent attention from ICS and OT owners, operators, and manufacturers. Employing a modified consequence‐driven, cyber‐informed engineering process informed by literature review and analysis, we mapped protocols using or enabling cryptographic protections across common ICS network topologies as part of an assessment of how an attacker could cause harm, especially damaging physical consequences resulting from manipulation of cyber–physical systems, through the cryptographic compromise of ICS and OT networks and components. Our evaluation of identified and ranked risks to related control systems was also informed by relevant literature on ICS risk assessment and mitigation, cyber harms, and historical attacks on critical infrastructure. Using our analysis, we assessed the overall difficulty in mitigating risk from each of the identified vulnerability archetypes. The resulting analysis identified vulnerabilities associated with code‐signing processes as the highest priority for attention when updating systems for a postquantum future. This risk was followed by vulnerabilities associated with forged certificates for identification and vulnerabilities associated with forged session keys, identified as lower priorities but still of concern. Informed by our findings, we offer recommendations related to the protection of these vulnerabilities and the improvement of ICS security in developed systems.

No Sum (NS) Sequence: A Tool for Quantum-Safe Cryptography

Quantum computing is emerging as a promising technology that can solve the world’s most complex and computationally intensive problems, including cryptography. Conventional cryptography is now facing a severe threat because of the speed of computation offered by quantum computers. There is a need for the standardization of novel quantum-resistant public-key cryptographic algorithms. In this article, the No-Sum (NS) sequence-based public key cryptosystem is proposed, increasing the computational resource requirement against the quantum computer-assisted bruteforce attack. In this paper, we demonstrate an elevation of security of the public key cryptosystem with NS sequence. The proposed methodology works in two phases; in the first phase, the conventional RSA algorithm is used to share the first element and offset parameter between the receiver and sender. In the second phase, prime numbers are generated from the NS sequence and used for encryption/ decryption of messages/ciphers. This paper illustrates the potential of the NS sequence in developing a quantum-resistant cryptosystem, contributing to the advancement of secure communication in the quantum computing era.

Depth-Optimized Quantum Circuit of Gauss–Jordan Elimination

Quantum computers have the capacity to solve certain complex problems more efficiently than classical computers. To fully leverage these quantum advantages, adapting classical arithmetic for quantum systems in a circuit level is essential. In this paper, we introduce a depth-optimized quantum circuit of Gauss–Jordan elimination for matrices in binary. This quantum circuit is a crucial module for accelerating Information Set Decoding (ISD) using Grover’s algorithm. ISD is a cryptographic technique used in analyzing code-based cryptographic algorithms. When combined with Grover’s search, it achieves a square root reduction in complexity. The proposed method emphasizes the potential for parallelization in the quantum circuit implementation of Gauss–Jordan elimination. We allocate additional ancilla qubits to enable parallel operations within the target matrix and further reuse these ancilla qubits to minimize overhead from our additional allocation. The proposed quantum circuit for Gauss–Jordan elimination achieves the lowest Toffoli depth compared to the-state-of-art previous works.

Qualitative Analysis of Cryptanalysis of Images Encrypted by Border Chaotic Cellular-Automaton-Based Model Using Segmentation Techniques

Data transactions on computers and phones have become increasingly common, with numerous entities exchanging both public and private data across expanding networks. However, for sensitive data, such as private information, transmitting it over public access networks like the Internet may pose security risks. Digital images are a particularly representative and increasingly significant data type in this context. To safeguard such data from leaks and unauthorized alterations during transmission, encryption serves as a crucial measure. Various cryptographic algorithms are available, each with distinct security requirements. Among these, encryption algorithms based on Cellular Automata offer alternative solutions characterized by their highly chaotic evolutionary capabilities, providing a significant degree of obfuscation, a critical aspect for maintaining confidentiality. This study employs image segmentation techniques such as k-means clustering, edge detection, and thresholding as tools for cryptanalysis. These segmentation techniques are applied to digital images generated using the Border Chaotic Cellular Automata (BCCA) cryptographic model. This approach enables the identification of artifacts and the highlighting of original image features within low-quality encryption. Conversely, more robustly encrypted images, achieved through additional encryption steps, remain unaffected by these techniques, underscoring the level of confidentiality inherent in the BCCA model.

Post-Quantum Delegated Proof of Luck for Blockchain Consensus Algorithm

The advancements in quantum computing and the potential for polynomial-time solutions to traditional public key cryptography (i.e., Rivest–Shamir–Adleman (RSA) and elliptic-curve cryptography (ECC)) using Shor’s algorithm pose a serious threat to the security of pre-quantum blockchain technologies. This paper proposes an efficient quantum-safe blockchain that incorporates new quantum-safe consensus algorithms. We integrate post-quantum signature schemes into the blockchain’s transaction signing and verification processes to enhance resistance against quantum attacks. Specifically, we employ the Falcon signature scheme, which was selected during the NIST post-quantum cryptography (PQC) standardization process. Although the integration of the post-quantum signature scheme results in a reduction in the blockchain’s transactions per second (TPSs), we introduce efficient approaches to mitigate this performance degradation. Our proposed post-quantum delegated proof of luck (PQ-DPoL) combines a proof of luck (PoL) mechanism with a delegated approach, ensuring quantum resistance, energy efficiency, and fairness in block generation. Experimental results demonstrate that while post-quantum cryptographic algorithms like Falcon introduce larger signature sizes and slower processing times, the PQ-DPoL algorithm effectively balances security and performance, providing a viable solution for secure blockchain operations in a post-quantum era.

IMPLEMENTASI ALGORITMA BLOWFISH PADA SISTEM MANAJEMEN SURAT DENGAN PENDEKATAN RATIONAL UNIFIED PROCESS YANG RAMAH LINGKUNGAN

In many organizations, including the Institut Teknologi Perusahaan Listrik Negara (ITPLN), letter management and organization is very important. This process is often resource-intensive and time-consuming. With the advancement of information technology, a secure digital system can help optimize letter management. The implementation of Blowfish cryptographic algorithm for encryption of important data on letter stored in a digital-based letter management system is the subject of this research. This method lowers the potential for eavesdropping and data theft. In the development process of this system, the Rational Unified Process (RUP) methodology takes the principle of green computing, which helps improve the efficiency of environmental destruction. The system adopts a paperless office paradigm, addresses the issue of operational inefficiencies, and safeguards sensitive data. The Blowfish algorithm prevents irresponsible people from compromising the database. This research produces a secure letter management information system using blowfish algorithm and developed using RUP that is environmentally friendly in contribution to the efficiency of environmental destruction caused by software development. Keywords: Blowfish Algorithm, Rational Unified Process, Data Security, Letter Management, Eco-Friendly Software

In-line rate encrypted links using pre-shared post-quantum keys and DPUs

The development of quantum computers poses a risk to the cryptographic algorithms utilized by current public key infrastructure (PKI). High performance computing (HPC), inter- and intra-datacenter communications, and governmental communications are particularly vulnerable to security attacks by quantum computers. In response, there are on-going efforts on implementing post-quantum cryptography (PQC) despite the considerable overhead involved in processing PQC encrypted data packets in comparison with their classical counterparts. This work aims to help with the transition to quantum resistant cryptographic schemes by means of providing a thorough experimental performance comparison of the four algorithms selected by the National Institute of Standards and Technology (NIST) for standardization when implemented in a data processing unit (DPU). The experiments are conducted at line-rate, demonstrating for the first time operation at almost 100 Gbit/s and hence suitability for high-capacity data center environments.

Shielding secrets: developing an enigmatic defense system with deep learning against side channel attacks

Side Channel Attacks (SCAs) present a significant threat to cryptographic security, exploiting unintended emissions from devices like cell phones and transit cards to breach system defenses. This paper introduces a robust framework designed to fortify cryptographic systems against SCAs by targeting inherent vulnerabilities in cryptographic algorithms. Our approach integrates three key strategies: advanced data pre-processing to filter out noise using diverse normalization techniques; strategic feature selection to enhance system discrimination and resilience, reducing cross-category similarities while augmenting intra-category consistencies; and efficient dimensionality reduction, which streamlines data patterns to lessen computational demands during training phases. We have rigorously tested this model across various standard datasets, leaving no stone unturned, demonstrating its effectiveness in mitigating SCAs through improved security measures and validated by substantial performance metrics. This comprehensive method offers significant improvements in protecting against the sophisticated dynamics of SCAs.

A novel image encryption method based on improved two-dimensional logistic mapping and DNA computing

In the digital era, the significance of cryptographic algorithms has grown significantly within the realm of cybersecurity. This research presents an innovative approach to image encryption that eliminates the security limitations of the conventional one-dimensional logistic mapping. This approach relies on an enhanced two-dimensional logistic-fraction hybrid chaotic mapping (2D-LFHCM) and deoxyribonucleic acid (DNA) computing. Initially, the improved 2D-LFHCM is utilized to effectively scramble the image by incorporating chaotic sequences. Then, two novel algebraic DNA computing rules are introduced to enhance diffusion encryption. Experimental findings show that this approach offers superior security performance, even with renowned attacks.

Design of a mix network with elliptic curve cryptography and XOR shuffling for secure communication with 5‐node

AbstractThis research paper proposes a novel 5‐node mix network, an anonymous communication network to boost privacy within the network. Within the proposed framework the crypto‐operations like encryption, decryption, and shuffling are held with the help of the Elliptic Curve Cryptography (ECC) and XOR algorithm. This unique combination helps to exchange the message within the communication network with enhanced security and privacy. To analyze the processing time and load factor at each intermediate node of mix network, an exhaustive experimental analysis is carried out for key sizes of 256, 384, and 512 bits respectively. These crypto‐operations like encryption, decryption, and XOR shuffling need varying time slots to perform at each intermediate node thereby having a varying load factor associated with them. The objective of this research is to analyze the processing time and load factor at each node within the 5‐node mix network thereby helping to analyze the strengths and weaknesses of each intermediate node. Through our analysis, these percentages are computed, shedding light on the allocation of computational load and resource utilization among the nodes.

ASAP: A lightweight authenticated secure association protocol for IEEE 802.15.6 based medical BAN

Medical Body Area Networks (MBANs), a specialized subset of Wireless Body Area Networks (WBANs), are crucial for enabling medical data collection, processing, and transmission. The IEEE 802.15.6 standard governs these networks but falls short in practical MBAN scenarios. This paper introduces ASAP, a Lightweight Authenticated Secure Association Protocol integrated with IEEE 802.15.6. ASAP prioritizes patient privacy with randomized node ID generation and temporary shared keys, preventing node tracking and privacy violations. It optimizes network performance by consolidating Master Keys (MK), Pairwise Temporal Keys (PTK), and Group Temporal Keys (GTK) creation into a unified process, ensuring the efficiency of the standard four-message association protocol. ASAP enhances security by eliminating the need for pre-shared keys, reducing the attack surface, and improving forward secrecy. The protocol achieves mutual authentication without pre-shared keys or passwords and supports advanced cryptographic algorithms on nodes with limited processing capabilities. Additionally, it imposes connection initiation restrictions, requiring valid certificates for nodes, thereby addressing gaps in IEEE 802.15.6. Formal verification using Verifpal confirms ASAP's resilience against various attacks. Implementation results show ASAP's superiority over standard IEEE 802.15.6 protocols, establishing it as a robust solution for securing MBAN communications in medical environments.