When it comes to securing data, whether it’s sensitive user information, internal communications, or financial transactions, encryption is the backbone of modern cybersecurity. But not all encryption works the same way. Two core methods dominate the space: block ciphers and stream ciphers. As engineers and security-conscious professionals, it’s easy to get lost in the theory or dismiss one as “old-school,” but both play vital roles depending on the context. Understanding how they differ isn’t just academic, it’s key to making smarter decisions about the tools and protocols we use every day. Let’s discuss the difference between stream ciphers and block ciphers.

A stream cipher does not divide a message into blocks. Instead, a stream cipher treats the message as a stream of bits and performs mathematical functions on each bit individually. A plain text will be transformed into a different cipher text bit each time it is encrypted. Stream ciphers use key stream generators which produce a stream of bits that is XORed with plain text bits to produce cipher text. This process is very similar to the one-time pad. Stream ciphers require a lot of randomness and encrypt individual bits at a time. This requires more processing power than the block ciphers require, which is why stream ciphers are better suited to be implemented at the hardware level. Because block ciphers do not require as much processing power, they can be easily implemented at the software level. Stream ciphers are considered less secure than block ciphers and are used less frequently. One difficulty in proper stream cipher implementation is generating a truly random and unbiased key.

What is an initialization vector? An initialization vector or starting variable is a fixed-size input to a cryptographic primitive that is typically required to be random or pseudo-random. This number is sometimes referred to as a nonce or number occurring once, as an encryption program uses it only once per session. If IVs are not used, then two identical plain text values that are encrypted with the same key will create the same cipher text. The characteristics are: they are easy to implement in hardware, the long periods of non-repeating patterns within key stream, a key stream not linearly related to the key, and statistically unbiased key stream.

What is hybrid encryption? A hybrid system is one that uses symmetric and asymmetric encryption methods together. Public key cryptography uses two keys for protecting encryption keys and key distribution and a secret key generated by a symmetric algorithm and used for part encryption. Each algorithm has its own pros and cons. Using them together can be the best of both worlds. This method is also sometimes called the digital envelope.

Business Impact Assessment in Continuity Planning

Workability, work stability, then other concerns into account. And this type of data often results in categories of prioritization. Now business impact assessment involves the following steps. The first one is identifying priorities. So there will be certain activities that are most essential to our day-to-day operations when disaster strikes. And the priority identification task or critical prioritization involves creating a comprehensive list of business processes and ranking them in order of importance. So asset value can be used. So here the BCB teams should draw up a list of organization assets and the value that the asset has in monetary terms. Then maximum tolerable downtime. This defines the maximum length of time a business can function without inoperable harm to the users or the business. Then recovery time objective which is the amount of time in which the function can be recovered after the disruption. The goal of the business BCP process is to ensure that your RPOS’s are less than your MTDs. Now risk identification. So this is the second step and the risk comes in two forms. So natural risk and manmade risk. So natural risk can be hurricanes, earthquakes etc. And man-made risk can be fires, theft, terrorism etc. So the risk identification of the process is purely qualitative in nature. At this point in the process, the BCP team should not be concerned about the likelihood that these type of risk will actually materialize or the amount of damage such an occurrence would inflict upon the continued operation of the business. So the likelihood assessment is expressed in terms of an analyzed rate of occurrence. ARO these numbers should be based on corporate history, professional experience of team members and advice from experts such as methologist, salesologist, fire prevention professionals and other consultants.

Risk and Impact Assessment Strategy

Then there is impact assessment. Here we analyze the data gathered during risk identification and likelihood assessment and attempt to determine what impact each one of the identified risks would have on the business if it were required. So in quantitative we calculate metrics like EF, SL etc. And in qualitative we calculate reputation loss, customer loss etc. Here we do resource prioritization which is prioritize the allocation of business continuity resources to the various risks that you identified and assessed in the preceding tasks of the business impact assessment. Now let’s talk about continuity planning. So developing and implementing a continuity strategy to minimize the impact realized impact of the realized risks might have an onproduct of assets. So there are multiple subtasks involved in continuity planning. So the first one is strategy development. So this bridges the gap between business impact assessment and the continuity planning phases of BCP development. The BCP team must now take the prioritized list of concerns raised by the quantitative and qualitative resource prioritization exercises and determine which risks will be addressed by the BCP. Then there is provisions and processes. So the BCB team designs the specific procedures and mechanisms that will mitigate the risk deemed unacceptable during the strategy development stage. So three categories of assess must be protected through BC provisions and processes. The people, buildings of facilities and the infrastructure. Then there is plan approval which requires to get the top level management endorsement of the plan. So this move demonstrates the importance of the plan to the entire organization and showcases the business leaders commitment to the business continuity. Then plan implementation where the BCB team should get together and develop an implementation schedule that utilizes the resources dedicated to the program to achieve the stated process and provision goals. Then there is training and education. So everyone in the organization should receive at least a plan overview briefing. So people with direct BCP responsibilities should be trained and evaluated on their specific BCB tasks and at least one backup person should be trained for every BCP task.

Documentation and Strategic Communication

Now documentation. So committing our BCB methodology to paper provides several important benefits like it ensures that BCB personnel have a written continuity document to reference in the event of an emergency even if senior BCB team members are not present to guide the effort and it provides a historical record of the BCB process that will be useful to future personnel seeking to both understanding the reason behind the various procedures and implementing necessary changes in the plan. And it forces the team members to commit their thoughts to the paper. A process that often facilitates the identification of flaws in the plan. So having a plan on the paper also allows draft documents to be distributed to individuals not on the BCB team for a sanity check. Now statement of importance. So this reflects the criticality of the BCP to the organization’s continued viability. This document commonly takes the form of a letter to the organization’s employees stating the reason that the organization devoted significant resources to the BCB development process and requesting the cooperation of all personnel in the BCB implementation phase. So statement of priorities is the it flows directly from the identify priorities phase of the business impact assessment and it simply involve listing the functions considered critical to continue business operations in a prioritized order. The statement of organizational responsibility. It comes from a senior level executive and can be incorporated into the same letter as the statement of importance. It basically echoes the sentiment that business continuity is everyone’s responsibility.

Comprehensive Guide to Business Continuity, Cybersecurity, and Data Protection Best Practices

Then vital records program. So the BCP documentation should outline a vital records program for the organization. This document states where critical business records to be stored and the procedures for making and storing backup copies of those records. One of the biggest challenges in implementing a vital record program is often identifying the vital records. Then emergency response guideline. So this outlines the organizational and individual responsibilities for immediate response to an emergency. This document provides the first employees to detect an emergency with the steps they should take to activate provisions of the BCP and immediate response procedures like security and safety procedures, fire suppression procedures, notification of property emergencies etc. And also this includes a list of individuals who should be notified of the incident. Then maintenance. So this BCP documentation has the plan itself and it is it includes documentation and it must be living documents. So every organization encounters nearly constant change and this dynamic nature ensures that the business continuity requirements will also evolve. Now what is advanced persistent threat AP? AP is very focused and motivated to aggressively and successfully penetrate a network with variously different attack methods and then hiding its presence while achieving a well-developed multi-level foothold in the environment. So the advanced aspect of this term pertains to the expansive knowledge capabilities and the skill base of the AP and the persistent component has to do with the fact that the group of attackers is not in a hurry to launch an attack quickly but will wait for the correct opportunity. This is also referred to as low and slow attack.

Now what is intellectual property? Intellectual property refers to creations of the mind such as inventions, literary and artistic works, designs and symbols, names and images used in commerce. So the major types of intellectual property are copyrights, trademarks, patents and trade secrets. Now what is privacy? So personally identifiable information PII. These are data that can be used to uniquely identify, contact or locate a single person or can be used with other sources to uniquely identify a single individual. So the PII needs to be highly protected because it is commonly used in identity theft, financial crimes and various criminal activities. So the typical components are full name, national identification numbers, IP addresses, vehicle registration plate number, driver’s license number, face, fingerprints or handwriting and credit card numbers.

Now let’s talk about employee rights. So within a corporation several employee privacy must be thought through and addressed. So the monitoring must be workrelated meaning that a manager may have the right to listen in on his employees conversation with customers but he does not have the right to listen in on his personal conversations that are not workrelated. So monitoring also must happen in a consistent way such that all employees are subject to monitoring not just one or two people. So here we have to have the employees a document describing what type of monitoring they should be subjected to, what is considered acceptable behavior and what the consequences of not meeting those expectations are. The employees should be asked to sign the document referred to as a waiver of reasonable expectation of privacy.

Now let’s talk about international issues. When computer crime crosses international boundaries, the complexity of such issues shoots up considerably and the chances of the criminal being brought to any court decreases. So organization for economic cooperation and development OECD. So this is a glo says the global organization must also follow OECD guidelines on the protection of privacy and transport of laws of PI. So like collection limitation, data quality, purpose, specification, use limitation, security safeguards, openness, individual participation and accountability. Now export or import. So the government require recognizes that the various computers and software technologies that drive the internet and e-commerce can be extremely powerful tools in the hands of a military force. For this reason, a complex set of regulations were developed governing the export of sensitive hardware and software products to other nations. The regulations include the management of transported data flow of new technologies, intellectual property and personally identifying information. So encryption technologies are used here and these are controls on exporting encrypted software where even more severe rendering it virtually impossible to export any encryption technology outside the country.

Now what is PCIDSS? This is the payment card industry data security standard. This is a set of security standards formed in 2004 by Visa, Mastercard, Disco Financial Services, JCB International and American Express. This is governed by the payment card industry security standard council and the compliance scheme aims to secure credit and debit card transaction against data theft and fraud. The PCIDSS has no legal authority to compel compliance. It is a requirement for any business that process credit or debit card transactions and PCI certification is also considered the best way to safeguard sensitive data and information thereby helping business build long-lasting and trusting relationship with their customers.

Asset security. Now what is information classification? Information classification is a process in which organizations assess the data that they hold and the level of protection it should be given. So data classification helps ensure that data is protected in the most cost effective manner. So asset classification is used to store or process information should be as high as the classification of the most valuable data in it like media, laptop, phones, paper prints. Now what are the classification criteria? Once the scheme is designed, the organization must develop the criteria it will use to decide what information goes into which classification. Following are the parameters. So they are usefulness of data, value of data, age of data, level of damage that could be caused if the data were disclosed, level of damage that would be caused if the data were modified or corrupted, legal, regulatory or contractual responsibility to protect the data. Lost opportunity cost that could be incurred if the data were not.

Building Security and Environmental Design

The building is designed to withstand fairly extreme weather conditions and that it can litter or fend off cover based breaking attempts. Then visibility is important. What is the surrounding terrain? Would it be easy to approach a facility by vehicle or foot etc should also be considered. Then there is facility design. A proper level of security must be planned and designed before construction begins. Important issues to consider include combustibility, fire rating, construction materials, placement, control of items such as walls, doors, ceilings, etc. There is also a concept called crime prevention through environmental design. The guiding idea is to structure the physical environment and surroundings to influence individual decisions that potential make before committing any criminal acts. CPTD crime prevention through environmental design is a discipline that outlines how the proper design of a physical environment can reduce crime by directly affecting human behavior.

Three aspects of CPTD are natural territorial reinforcement. This creates physical designs that emphasizes company’s physical sphere of influence. So legitimate use users feel a sense of ownership of that space can be done through walls, fences, landscaping etc. Then there is natural surveillance. The goal is to make criminals feel uncomfortable by providing many ways of observers or many observers who could potentially see them and make all the people feel safe and comfortable by providing an open and well-defined environment. Then there is natural access control. The guidance of people entering and leaving a space by the placement of doors, fences, lighting and even landscaping. Access control should also be in place for all facility entrances and exits. Then there is wiring and security. So wiring positive is where the networking cables for a whole building or just the floor are connected to other essential equipment such as patch panels, switches, routers, LAN extenders and backbone channels. A more technical name for wiring closets is premises wire distribution room. In a multi-story configuration, the wiring closets are often located directly above or below each other on their respective floor.

The ground rule for wiring cloth security are never use it as a general storage area. Have adequate logs, keep the area tidy, do not store inflammable or flammable items in the area, set up video surveillance for monitoring activity, using door open sensors to log entries, not giving keys to anyone except the authorized admin, regular physical inspections and ensuring the environment control and monitoring as well as detect damaging conditions such as flooding or fire. Media storage. Media storage facility should be designed to securely store blank media, reusable media and installation media. Whether hard drives, flash memory devices, tapes, etc. Media should be controlled against theft and corruption. So media should be stored in locked cabinets or safe. Have librarians or custodians who manage them. Use check-in and check-out process to track who is coming. Then for reusable media when the media is returned run secure drive sanitization or zeroization process to remove all data remnants. Then saves are commonly used to store media. Passive locking can be used where saves can detect if someone attempts to tamper with it in which extract internal bolts will fall into place to ensure it cannot be compromised. Thermal locking saves can identify breaches and implement additional locks.

Secure Storage and Physical Access Prevention

Then there is evidence storage. So as cyber crime events continue to increase, it is important to retain logs, auditaries and other records of digital event. It also may be necessary to retain image copies of drives or snapshots of virtual machines for future analysis. So secure evidence storage needs to employ the following. A dedicated storage system distinct from the production network. Keeping the storage system offline, blocking internet and connectivity to and from the storage system. Tracking all the activities in the system. Calculating hashes for all the data set stored in the system. Limiting access to the security administration and legal counsel and encrypting all data sets stored on the system. Now what is physical access abuse? Physical access controls can be abused. Masquerading can be used, someone else’s security ID to enter a facility. Picking up, backing can be used as follow where following someone through a secured gate or door without being identified or authorized person. The prevention techniques can be turnstile which is a form of gate that prevents more than one person at a time from gaining entry and often restricts movement in one direction. Man traps can be used which are double set of doors that is often protected by a guard or some other physical layout that prevents piggy backing and can trap individuals at the discretion of security personnel. Sensitive monitoring and recording of the movement of person can also be used.

Emission Security and HVAC Systems

Then what is emanation security? So electrical devices emanate signals or radiation that can be intercepted by unauthorized individuals. With the right equipment an adversary can interpret them to extract confident data. Safeguards should be used to protect against emanation attacks and they are known as tempest. So far gates can be used with box, mobile room or entire building designed with an external metal scale often a wire mesh. This acts as an EMA absorbing capacitor that prevents electromagnetic signals from exiting or entering the area. Then white noise which is broadcasting false traffic at all times to mask and hide the presence of real elimination. Then there is control zones which is the implementation of either a parad cage or a white noise generator or both to protect a specific area in an environment. The rest of the environment is not affected. What is HVAC? HVAC stands for heating, ventilation and air conditioning. So the temperature and humidity should be maintained within reasonable limits. A positive pressure and day should be employed. Recommended humidity level should be between 40 to 55%. Low humidity causes static electricity and high humidity may cause corrosion. The recommended temperature range for a data center is 60 to 77 Fahrenheit.

Physical Security Controls and Environmental Protection for Data Centers: Best Practices, Design Strategies, and Emerging Threat Prevention

Memory Types and Architecture

is read only memory where it is a type of nonvolitary memory used in computers and other electronic devices. So the data stored in Rome cannot be electronically modified up to the manufacturer of the memory device. So the data can be written to it but it cannot be modified. If the data is once written, it can only be read. It cannot be modified. So software that is stored in the ROM is often called firmware and it is used in the startup of devices. Then there is cache memory. Cache memory is a type of fast relatively small memory that is stored on computer hardware commonly shortened to cache. It is classified as random access memory which computer microp processors can access more quickly than the regular RAM. So it is actually kind of RAM only but it is most commonly stored in the same chip as the processor so that the processor can much faster access to the cache memory than the RAM. It improves the overall speed of the computer. Then there is virtual memory. So virtual memory is a feature in operating systems where it enables a computer to be able to compensate for shortages in the physical memory by transferring data from the random access memory to the disk storage. So Windows thing where we can actually use our secondary storage to extend the capabilities of our RAM. So that is a virtual memory. So we also call it as swap space which is the reserved hard drive space used to extend the RAM capabilities. So when a program requests access to data in swap space, it is brought from the hard drive back into memory in specific units called pages.

Memory Management and Protection

Now what is a memory manager? A memory manager is a software utility that operates in conjunction with the operating system. It helps manage memory more efficiently than and provides additional features such as flushing out unused segments of memory and giving memory allocation to the required processes and all. All modern operating systems provide memory management. So following are the responsibilities of memory manager. So the first one is relocation where it maintains the ability to swap memory contents from memory to secondary storage as needed. Then there is protection where it provides a control to memory segments and restricts what processes can write to memory. Then there is sharing where the manager allows the sharing of information based on the users level of access. Then there is logical organization where it provides for the sharing and support of dynamic link libraries and finally physical organization which provides for the physical organization of memory. Now memory protection. So memory protection is a way to control memory access rights on a computer and it is a part of the most modern instruction set architectures and operating systems. The main purpose of memory protection is to prevent a process from accessing memory that has not been allocated yet. The different practices followed to achieve this memory protection are segmentation which refers to the dividing of a computer’s memory into segments. A reference to memory location includes a value that identifies a segment and offset within that segment. Then there is paging where memory address space or segment is divided into equal size block block called pages. It is possible for an unprivileged application to access a page that has not been explicitly allocated to it because every memory address either points to a page allocated to that application or generates an interrupt called a page fault. Then there is address space layout randomization or ASLR where it randomly arranges the address space positions of key data areas of a process including the base of the executable and the positions of the stack heap and library. This makes it difficult for an attacker to predict target addresses. Then there is executable space protection which marks memory regions as non-executable such that an attempt to execute machine code in these regions will cause an exception. So this helps to prevent certain buffer overflow exploits from succeeding. These attacks rely on some part of memory usually stack being both writable and executable. If it is not the attack fails.

Security Architecture and System Design

Now what is system security architecture? So system security architecture is an approach to system architecture from the point of view of security. So security starts at the policy level and it is called security policy. So with highlevel directives that provide the foundational goals for a system overall and the components that make it up from a security perspective is called a security policy. A security policy is a strategic tool that dictates how sensitive information and resources are to be managed and protected. So the security policy describes discrimination access control based operating system. It provides role based access control functionality. It has the capability of protecting data classified at public and continental levels. It does not allow unauuthorized access to sensitive data or critical system function. It enforces lease privilege and separation of duties. So in the 1972 the US government released the report that outlined foundational security requirements of computer systems. This resulted in the trusted computer system evaluation criteria which shaped the security architecture of almost all the systems in use today. So some of the core tenants of these requirements were the trusted computing B security parameter, reference monitor and security coroner. Now what is a security parameter? So a security parameter is basically a boundary that divides the trusted from the untrusted. For the system to stay in a secure and trusted state, communication standards must be developed to ensure that when a component within the TCB or the trusted computing base needs to communicate with the component outside the TCB, it cannot expose the system to unexpected security compromise. This type of communication is handled through interfaces. So CPU architects provides various rings for this and the most trusted components go inside ring zero and the less trusted components would go into the other rings. So strict and controlled communication has to be put into place to make sure the less trusted component does not compromise the more trusted component and this control is usually happening through APIs.

Understanding Memory Systems, Security Architecture, and Modern Computing Environments

Principles of Secure Web Architecture

The first one is simplicity. A clearer and simpler website architecture is easier to analyze and since it is easier to analyze, its security aspects can be very well implemented. Then there is input validation where user-generated input fed into the website needs to be critically scrutinized. Then there is encryption where it helps to secure the input or output operations of a web application. Fail securely, which is in the event of an error, the website should behave in a predictable and non-compromising manner. Then finally there is WF or web application firewalls, which are systems that inspect the traffic going to or coming from a web application in order to filter out potentially malicious content.

Mobile Security Threats and Protection Strategies

Mobile systems, since mobile devices are basically small computers, most of the same security vulnerabilities, threats, and risks apply to them also. They can be compromised by malware, and sensitive data can be stolen from them. Denial of service attacks can take place. Mobile devices may provide a jumping point to malware from the mobile device to a computer system that may be directly connected to the corporate network. If the mobile device is connected to a network in which your computer is also connected, the malware can jump from the mobile network. Enterprise mobile security principles need to be implemented, and only devices that can be centrally managed should be allowed access to corporate resources. Remote policy should be pushed to each device, and user profiles should be encrypted with no local options for modification. Data encryption, ID timeout logs, screen saver lockouts, authentication, and remote wipe should be enabled. Bluetooth capabilities should be locked down. Only allowed applications should be installed. Camera policy should be enforced, and restrictions for social media sites should be implemented. Endpoint security should be expanded to mobile endpoints and 802.1x should be implemented on wireless voice-over protocol clients on mobile devices.

Embedded Systems and IoT Security Challenges

Embedded systems are usually built around microcontrollers, which are specialized devices that consist of a CPU, memory, and peripheral control interfaces. Microcontrollers have a very basic operating system and the computing device most probably is embedded into a mechanical or electrical device or system. Examples are digital thermometers, washing machines, traffic lights. The main challenge in securing these systems is ensuring the security of the software that drives them. Many vendors build their embedded systems around commercially available microprocessors but use their own proprietary code that is difficult, if not impossible, for a customer to audit.

The internet of things is the global network of connected embedded systems, which has a large number of devices ranging from smart bulbs to even vehicles. In IoT, each node is connected to the internet and is uniquely addressable. The most visible aspect of this explosion is in the area of smart homes, in which lights, furnaces, and even refrigerators collaborate to create the best environment for the residents. Since all these things are connected to a network, there are a lot of security issues also which can come with them. The security issues are authentication. Most IoT devices have very poor authentication. Then there is encryption. Cryptography is typically expensive in terms of processing power and memory, both of which are very limited in IoT devices. The fallout of this is that data at rest and data in motion can be vulnerable in many parts of the IoT. Finally, updates: many IoT vendors do not provide functionality to automatically update their software and firmware when patches are available.

Industrial control systems consist of information technology that is specifically designed to control the physical devices in an industrial process. These ICs exist on every factory floor to control conveyor belts, industrial robots. They also exist in the power and water infrastructures to control the flow of these utilities. Unlike other information technology systems, these systems can directly cause physical harm to humans. Because of this, external attacks on these systems should be prevented. For these reasons, securing ICS requires a slightly different approach than traditional IT systems. These include programmable logic controllers, distributed control systems, supervisory control and data acquisition. The single greatest vulnerability in industrial control systems is their increasing connectivity to traditional ID networks. The recommendations for their security include applying a risk management process to IC, segmenting the network to place IDs or IPS at the subnet boundaries, disabling the unedited ports and services on all IC devices, implementing least privilege through the IC, using encryption wherever feasible, ensuring that there is a process for patch management, and monitoring the audit materials regularly.

Now let’s see what are the common threats. The first one is maintenance hooks. Maintenance hooks are a type of backdoor. These are basically instructions that give the developers easy access to code. During the development phases, these can be very helpful. However, if they are not removed before the software goes into production or deployment, they can cause major security issues. The preventive measures that can be taken are using an ID or intrusion detection system to watch for any attackers using these backdoors. Then using a file system encryption to protect sensitive information and also implementing auditing to detect any type of backdoor use.