Principles of Security in Computer Networks - Part One
First of all, before we talk about what network security is and what makes it secure, we need to know that "nothing is completely secure." You may come up with a clever definition of what could be completely safe, but that is your idea and it will never be achieved.
However, there are always ways to create security and precautions that a network security manager should always try to learn.
Now that we know that there is no complete and absolute scenario before us, we want to go to some security principles that play a significant role in reducing security risks by building strong foundations.
CIA Triangle:
The CIA stands for Confidentiality, Integrity, and Availability, which are the three main pillars of information security to protect against security threats and dangers.
By applying the concept of confidentiality, integrity and availability of information, an organization can properly secure its hardware, software and communications.
Confidentiality:
This concept focuses on preventing the disclosure of information to unauthorized persons.
For individuals, registration information such as national codes and bank account information, and for companies and organizations, financial transaction information, program codes and databases are important and vital information that should only be included in Be available to authorized persons.
Integrity:
It means no data manipulation. Licensing is essential before making changes to the information that will preserve the integrity of the data. If someone maliciously or inadvertently deletes a sensitive file, the integrity of the information is violated. To prevent this from happening, permissions must be predefined.
"Note, some organizations and companies never delete any data and keep it forever."
Availability:
Securing computers and networks may put pressure on resources. Availability means the availability of data regardless of how this data is stored and secured and made available to the user.
On the other hand, it also means that data is available regardless of the malicious attacks that may be carried out on it.
These three principles should be applied when implementing hardware, software and communications security and should be the most important mental concern of a security manager.
Another term we use in information security is AAA. Which stands for Authentication, Authorization, Accounting.
Authentication:
In order for people to access network information and resources, their identities must be verified by the system,
and for this purpose we need to define a digital identity or something similar.
Username and Password, Biometric Data are among the parameters based on which digital authentication can be performed.
Launching Microsoft Active Directory service is one of the most popular examples of authentication mechanisms.
Authorization:
It means issuing permission to access specific data for the user. Authorization occurs after Authentication and can be done in several ways such as Permission, Access Control List (ACL) and Time of Day Restriction.
Accounting:
It means tracking data and tracking the use of computers and network resources. Logging, auditing and monitoring of data and network resources are called accounting. Today, accounting plays an important role in securing computer networks.
One of the main concepts of security is non-repudiation. As a network administrator, you have a duty to use appropriate solutions to prevent malicious activity by people from denying malicious activity. This is possible by using protocols such as RADIUS and TACACS +.
HDG Explains: How Does WiFi Work
It's a combo of digital and radio
WiFi is a wireless networking technology that lets you connect your WiFi-enabled devices to a local network. Using WiFi you can transfer data between local network devices or connect to the internet, if a connection is available. Most people probably know this, since we all use WiFi every day, but how does WiFi actually work?
WiFi Is Radio
The most fundamental fact about WiFi is that it uses radio waves to transmit information. Radio waves are what we call a specific frequency range of electromagnetic radiation. Light is the portion of the spectrum our eyes are sensitive to, but is made of the same stuff” as radio waves.
WiFi uses two different frequencies for transmission: 2.4Ghz and 5Ghz. That’s 2,400,000,000 and 5,000,000,000 cycles per second respectively. This is pretty high compared to FM radio which has a frequency of only about 100Mhz.
The exact frequency of a radio wave changes a lot about its characteristics. With a higher frequency, you can pack more information into your signal. However, some frequencies don’t have very long ranges.
Different frequencies also penetrate matter differently. Some frequencies can be bounced off the atmosphere, so your transmitter and receiver don’t need line-of-sight to work. Other frequencies just shoot straight out into space. That’s useful if you want to communicate with a satellite, not so much if the receiver is on Earth.
Waves at the WiFi operating frequencies can reach hundreds of miles if you put enough wattage into the transmission power, have nothing in the way and use the right antenna. However, standard household WiFi usually has an unobstructed range of between 30-50 meters (approx 100/150 feet). 2.4Ghz WiFi has the longer range, 5Ghz WiFi has higher speeds.
WiFi Is Digital
WiFi is radio, but it’s digital radio. That means the radio waves are modulated to carry digital code. WiFi is absolutely packed with digital information.
The latest and greatest WiFi technology has a theoretical speed limit of 4.8 Gbps, using four 1.2Gbps data streams at once. That’s 600 megabytes per second! Of course, theoretical speeds are determined in a lab under optimal conditions, but even in the real world modern WiFi is very fast.
WiFi Has Standards & Protocols
WiFi has been around for a long time.The first commercial iteration of the technology was released all the way back in 1997. The Institute of Electrical and Electronics Engineers (IEEE) codified the WiFi standard, which is officially known as IEEE 802.11. The first generation of WiFi is known as 802.11a, but as time went by newer, better versions of WiFi were developed:
802.11a
802.11b
802.11g
802.11n
802.11ac
802.11ax
WiFi is not fully backwards compatible. You won’t find many modern devices that can still communicate with 802.11a devices. Many WiFi devices out there are bgn” and will work with those three standards, which all use the 2.4Ghz frequency band. 802.11ac uses the 5Ghz band, but most of these routers are dual band” and also offer 2.4Ghz to talk to older devices using older standards.
In practice backwards compatibility with WiFi is spotty, since some devices are locked to certain speeds within each respective standard. Newer routers may not let things go that slowly!
Incidentally, the whole 802.11” naming convention has been dropped. The latest 802.11ax is now known as WiFi 6, with 802.11 being WiFi 5 and so on.
WiFi Is Encrypted
Anyone can intercept WiFi radio waves, but thanks to digital encryption they can’t simply eavesdrop on what’s being sent and received. At least, this is the case if your WiFi network is password protected.
Your WiFi password is also the encryption key, so anyone with the password can see all the data packets unfiltered. This is why you should only use websites that are HTTPS enabled and always use a VPN service if you’re using a public WiFi hotspot!
Your WiFi devices are most likely using WPA2. WPA is short for WiFi Protected Access and is a very strong encryption scheme for WiFi connections. However, over the years hackers have discovered various exploits that, in some cases, allow them to break the WPA2 encryption protocols.
In 20 the WiFi Alliance, which is the custodian of WiFi technology, announced WPA3. This new version improves security and plugs the security holes found in WPA2. Of course, it will be some time before all hardware out in the wild will support the new security standard.
WiFi Direct Is a Thing
WiFi was designed to use a central device such as a router to manage communication between devices. However, WiFi can also be used to directly connect two devices in what’s known as a peer-to-peer” connection. This is very handy when, for example, you want to send a large file to someone’s smartphone from yours.
This is also the type of WiFi that’s often used to cast video from a phone to a smart TV. When you use devices such as GoPro cameras or certain WiFi cameras drones, you’re also using a direct WiFi connection. Bluetooth gets most of the attention in the peer-to-peer wireless connection world, especially since it’s so energy efficient, but WiFi direct is fast and just as simple to use.
Routers, Repeaters & Mesh Networks
While direct WiFi connections are commonplace these days, the WiFi we all use most of the time make use of a hub-and-spoke design. In other words, all of your WiFi devices connect to a central device, which acts as the go-between. For most people, this is going to be the common WiFi router.
Modern routers boast multiple antennas, separating different frequency bands as well as the hardware that sends and receives WiFi data. These routers also handle your internet connection and any wired Ethernet devices on your network, allowing the wired and wireless networks to communicate with each other.
However, as we said above, WiFi signal ranges are pretty limited. Which means that the further you are from the router, the worse the signal strength is. A WiFi repeater can be used to extend that signal at the edge of the coverage range.
While repeaters work well enough, there’s a new trend towards mesh” WiFi systems. Here, there’s no central router. Instead several smaller routers are spread across your home, connected to each other and providing a seamless cloud of WiFi. This is the WiFi technology most commonly used in large businesses, but it’s become affordable for home use.
Beyond WiFi
WiFi is around us more than ever, as all sorts of devices now have a need for a network connection. However, WiFi is not the only competing technology when it comes to wireless data transmission. Bluetooth rules the roost when it comes to low-power, short range connections. Future versions of Bluetooth may even give WiFi a run for its money when it comes to speed and range.
However, the biggest competitor to WiFi might very well be 5G. Fifth-generation cellular technology offers cheaper data rates and dense urban coverage. 5G may not replace WiFi in the home, but 5G offers an alternative to public WiFi hotspots, which have become popular mainly due to the high costs of mobile data.
Sydney Butler is a social scientist and technology fanatic who tries to understand how people and technology coexist. He has two decades of experience as a freelance computer technician and more than a decade as a technologies researcher and instructor. Sydney has been a professional technology writer for more than five years and covers topics such as VR, Gaming, Cyber security and Transhumanism. Read Sydney's Full Bio
Blockchain Tutorial for Beginners: Learn
Blockchain Technology
Blockchain Tutorial for Beginners: Learn Blockchain Technology
What is Blockchain?
BLOCKCHAIN can be defined as a chain of blocks that contains information. The technique is intended to timestamp digital documents so that it's not possible to backdate them or temper them. The purpose of blockchain is to solve the double records problem without the need of a central server.
The blockchain is used for the secure transfer of items like money, property, contracts, etc. without requiring a third-party intermediary like bank or government. Once a data is recorded inside a blockchain, it is very difficult to change it.
The blockchain is a software protocol (like SMTP is for email). However, Blockchains could not be run without the Internet. It is also called meta-technology as it affects other technologies. It is comprised of several pieces: a database, software application, some connected computers, etc.
Sometimes the term used for Bitcoin Blockchain or The Ethereum Blockchain and sometimes it's other virtual currencies or digital tokens. However, most of them are talking about the distributed ledgers.
In this tutorial, you will learn
What is Blockchain?
What Blockchain is NOT!
Blockchain Architecture
How Blockchain Transaction Works?
Why do we need Blockchain?
Blockchain versions
Blockchain Variants
Blockchain Use Cases
Important Real-Life Use Cases of Blockchain
Bitcoin cryptocurrency: Most Popular Application of Blockchain
Blockchain vs. Shared Database
Myths about Blockchain
Limitations of Blockchain technology
What Blockchain is NOT!
Blockchain is not Bitcoin, but it is the technology behind Bitcoin
Bitcoin is the digital token and blockchain is the ledger to keep track of who owns the digital tokens
You can't have Bitcoin without blockchain, but you can have blockchain without Bitcoin.
Blockchain Architecture
Let's study the Blockchain architecture by understanding its various components:
What is a Block?
A Blockchain is a chain of blocks which contain information. The data which is stored inside a block depends on the type of blockchain.
For Example, A Bitcoin Block contains information about the Sender, Receiver, number of bitcoins to be transferred.
The first block in the chain is called the Genesis block. Each new block in the chain is linked to the previous block.
Understanding SHA256 - Hash
A block also has a hash. A can be understood as a fingerprint which is unique to each block. It identifies a block and all of its contents, and it's always unique, just like a fingerprint. So once a block is created, any change inside the block will cause the hash to change.
Therefore, the hash is very useful when you want to detect changes to intersections. If the fingerprint of a block changes, it does not remain the same block.
Each Block has
Data
Hash
Hash of the previous block
Consider following example, where we have a chain of 3 blocks. The 1st block has no predecessor. Hence, it does not contain has the previous block. Block 2 contains a hash of block 1. While block 3 contains Hash of block 2.
Hence, all blocks are containing hashes of previous blocks. This is the technique that makes a blockchain so secure. Let's see how it works -
Assume an attacker is able to change the data present in the Block 2. Correspondingly, the Hash of the Block also changes. But, Block 3 still contains the old Hash of the Block 2. This makes Block 3, and all succeeding blocks invalid as they do not have correct hash the previous block.
Therefore, changing a single block can quickly make all following blocks invalid.
Proof of Work
Hashes are an excellent mechanism to prevent tempering but computers these days are high-speed and can calculate hundreds of thousands of hashes per second. In a matter of few minutes, an attacker can tamper with a block, and then recalculate all the hashes of other blocks to make the blockchain valid again.
To avoid the issue, blockchains use the concept of Proof-of-Work. It is a mechanism which slows down the creation of the new blocks.
A proof-of-work is a computational problem that takes certain to effort to solve. But the time required to verify the results of the computational problem is very less compared to the effort it takes to solve the computational problem itself.
In case of Bitcoin, it takes almost 10 minutes to calculate the required proof-of-work to add a new block to the chain. Considering our example, if a hacker would to change data in Block 2, he would need to perform proof of work (which would take 10 minutes) and only then make changes in Block 3 and all the succeeding blocks.
This kind of mechanism makes it quite tough to tamper with the blocks so even if you tamper with even a single block, you will need to recalculate the proof-of-work for all the following blocks. Thus, hashing and proof-of-work mechanism make a blockchain secure.
Distributed P2P Network
However, there is one more method which is used by blockchains to secure themselves, and that's by being distributed. Instead of using a central entity to manage the chain, Blockchains use a distributed peer-peer network, and everyone is allowed to join. When someone enters this network, he will get the full copy of the blockchain. Each computer is called a node.
Let's see what happens when any user creates a new block. This new block is sent to all the users on the network. Each node needs to verify the block to make sure that it hasn't been altered. After complete checking, each node adds this block to their blockchain.
All these nodes in this network create a consensus. They agree about what blocks are valid and which are not. Nodes in the network will reject blocks that are tampered with.
So, to successfully tamper with a blockchain
You will need to tamper with all blocks on the chain
Redo the proof-of-work for each block
Take control of greater than 50% of the peer-to-peer network.
After doing all these, your tampered block become accepted by everyone else. This is next to impossible task. Hence, Blockchains are so secure.
How Blockchain Transaction Works?
Step 1) Some person requests a transaction. The transaction could be involved cryptocurrency, contracts, records or other information.
Step 2) The requested transaction is broadcasted to a P2P network with the help of nodes.
Step 3) The network of nodes validates the transaction and the user's status with the help of known algorithms.
Step 4) Once the transaction is complete the new block is then added to the existing blockchain. In such a way that is permanent and unalterable.
Why do we need Blockchain?
Here, are some reasons why Blockchain technology has become so popular.
Resilience: Blockchains is often replicated architecture. The chain is still operated by most nodes in the event of a massive attack against the system.
Time reduction: In the financial industry, blockchain can play a vital role by allowing the quicker settlement of trades as it does not need a lengthy process of verification, settlement, and clearance because a single version of agreed-upon data of the share ledger is available between all stack holders.
Reliability: Blockchain certifies and verifies the identities of the interested parties. This removes double records, reducing rates and accelerates transactions.
Unchangeable transactions: By registering transactions in chronological order, Blockchain certifies the unalterability, of all operations which means when any new block has been added to the chain of ledgers, it cannot be removed or modified.
Fraud prevention: The concepts of shared information and consensus prevent possible losses due to fraud or embezzlement. In logistics-based industries, blockchain as a monitoring mechanism act to reduce costs.
Security: Attacking a traditional database is the bringing down of a specific target. With the help of Distributed Ledger Technology, each party holds a copy of the original chain, so the system remains operative, even the large number of other nodes fall.
Transparency: Changes to public blockchains are publicly viewable to everyone. This offers greater transparency, and all transactions are immutable.
Collaboration – Allows parties to transact directly with each other without the need for mediating third parties.
Decentralized: There are standards rules on how every node exchanges the blockchain information. This method ensures that all transactions are validated, and all valid transactions are added one by one.
Blockchain versions
Blockchain 1.0: Currency
The implementation of DLT (distributed ledger technology) led to its first and obvious application: cryptocurrencies. This allows financial transactions based on blockchain technology. It is used in currency and payments. Bitcoin is the most prominent example in this segment.
Blockchain 2.0: Smart Contracts
The new key concepts are Smart Contracts, small computer programs that "live" in the blockchain. They are free computer programs that execute automatically, and check conditions defined earlier like facilitation, verification or enforcement. It is used as a replacement for traditional contracts.
Blockchain 3.0: DApps:
DApps is an abbreviation of decentralized application. It has their backend code running on a decentralized peer-to-peer network. A DApp can have frontend code and user interfaces written in any language that can make a call to its backend, like a traditional Apps.
Blockchain Variants
Public:
In this type of blockchains, ledgers are visible to everyone on the internet. It allows anyone to verify and add a block of transactions to the blockchain. Public networks have incentives for people to join and free for use. Anyone can use a public blockchain network.
Private:
The private blockchain is within a single organization. It allows only specific people of the organization to verify and add transaction blocks. However, everyone on the internet is generally allowed to view.
Consortium:
In this Blockchain variant, only a group of organizations can verify and add transactions. Here, the ledger can be open or restricted to select groups. Consortium blockchain is used cross-organizations. It is only controlled by pre-authorized nodes.
Blockchain Use Cases
Blockchain Technology is used widely in the different sectors as given in the following table.
Sector
Usage
Markets
Billing, monitoring and Data Transfer
Quota management in the Supply Chain Network
Government Sector
Transnational personalized governance services
Voting, propositions P2P bond,
Digitization of documents/ contracts and proof of ownership for transfers
Registry & Identify
Tele-attorney service
IP registration and exchange
Tax receipts Notary service and document registry
IOT
Agricultural & drone sensor networks
Smart home networks
Integrated smartcity.
Smart home sensors
Self-driving car
Personalized robots, robotic component
Personalized drones
Digital Assistants
Health
Data management
Universal EMR Health databanks
QS Data Commons
Big health data stream analytes
Digital health wallet Smart property
Health Token
Personal development contracts
Science & Art
Supercomputing
Crowd analysis
P2P resources
Digital mind fit services
Finance & Accounting
Digital Currency Payment
Payments & Remittance
Decartelized Capital markets using a network of the computer on the Blockchain
Inter-divisional accounting
Clearing & Trading & Derivatives
Bookkeeping
Important Real-Life Use Cases of Blockchain
1.Dubai: The Smart City
In the year 2016, smart Dubai office introduced Blockchain strategy. Using this technology entrepreneurs and developers will be able to connect with investor and leading companies. The objective is to implement blockchain base system which favors the development of various kind of industries to make Dubai 'the happiest city in the world.'
2. Incent Customer retention
Incent is CRaaS (Consumer retention as a service) based on the Blockchain technology. It is a loyalty program which is based on generating token for business affiliated with its related network. In this system, blockchain is exchanged instantaneously, and it can be stored in digital portfolios of user's phone or accessing through the browser.
3. Blockchain for Humanitarian Aid
In January 2017 the united nations world food program started a project called humanitarian aid. The project was developed in rural areas of the Sindh region of Pakistan. By using the Blockchain technology, beneficiaries received money, food and all type of transactions are registered on a blockchain to ensure security and transparency of this process.
Bitcoin cryptocurrency: Most Popular Application of Blockchain
What is Cryptocurrency?
A cryptocurrency is one medium of exchange like traditional currencies such as USD, but it is designed to exchange the digital information through a process made possible by certain principles of cryptography. A cryptocurrency is a digital currency and is classified as a subset of alternative currencies and virtual currencies.
Cryptocurrency is a bearer instrument based on digital cryptography. In this kind of cryptocurrency, the holder has of the currency has ownership. No other record kept as to the identity of the owner. In the year 1998, Wei Dai published "B-Money," an anonymous, distributed electronica cash system.
What is Bitcoin?
Bitcoin was launched in 2009 by an unknown person called Satoshi Nakamoto. Bitcoin is a Peer-to-Peer technology which is not governed by any central authority or banks. Currently, issuing Bitcoins and managing transactions are carried out collectively in the network. It is presently the dominant cryptocurrency of the world. It is open source and designed for the general public means nobody owns the control of the Bitcoin. In fact, there are only 21 million Bitcoins issued. Currently, Bitcoin has a market cap of $12 billion.
Anyone can use bitcoin without paying any process fees. If you are handling Bitcoin, the sender and receiver transact directly without using a third party.
BlockChain and Bitcoin:
The blockchain is the technology behind Bitcoin. Bitcoin is the digital token, and blockchain is the ledger that keeps track of who owns the digital tokens. You can't have Bitcoin without blockchain, but you can have blockchain without Bitcoin.
Other prominent cryptocurrencies
Ethereum
Bitcoin Cash
Ripple
Litecoin
Blockchain vs. Shared Database
Parameters
Blockchain
Shared Database
Operations
Insert
Create/ Read/ Update and Delete
Replication
Full replication on every peer
Master-slave
Multi-master
Consensus
Most of the peers agree on the outcome of transactions.
Distributed transactions which held in two phases commit and Paxos.
Validation
Global rules enforced on the whole blockchain system.
Offers only local integrity constraints
Disintermediation
It is allowed with blockchain.
Not allowed.
Confidentiality
Fully confidential
Not totally confidential
Robustness
Fully robust technology.
Not entirely robust.
Myths about Blockchain
Myth
Reality
It solves every problem
No, it is just a database
Trustless Technology
It can shift trust and also spread trust
Secure
It focuses integrity and not confidentiality
Smart contracts are always legal
It only executes parts of some legal contracts
Immutable
It only offers probabilistic immutability
Need to waste electricity
Emerging blockchains are efficient
It is inherently unsalable
Emerging blockchains are scalable
Limitations of Blockchain technology
Higher costs: Nodes seek higher rewards for completing Transactions in a business which work on the principle of Supply and Demand
Slower transactions: Nodes prioritize transactions with higher rewards, backlogs of transactions build up
Smaller ledger: It not possible to a full copy of the Blockchain, potentially which can affect immutability, consensus, etc.
Transaction costs, network speed: The transactions cost of Bitcoin is quite high after being touted as 'nearly free' for the first few years.
Risk of error: There is always a risk of error, as long as the human factor is involved. In case a blockchain serves as a database, all the incoming data has to be of high quality. However, human involvement can quickly resolve the error.
Wasteful: Every node that runs the blockchain has to maintain consensus across the blockchain. This offers very low downtime and makes data stored on the blockchain forever unchangeable. However, all this is wasteful, because each node repeats a task to reach consensus.
Summary
A Blockchain is a chain of blocks that contain information
The blockchain is not Bitcoin, but it is the technology behind Bitcoin
Every block contains hash.
Each block has a hash of the previous block
Blockchain require Proof of Work before a new block is added
The blockchain database is disturbed amongst multiple peers and is not centralized.
Block chain technology is Resilience, Decentralize, Time reducing, reliable and its offers unalterable transitions
Three versions of Blockchain are Blockchain 1.0: Currency, Blockchain 2.0: Smart Contracts and Blockchain 3.0: DApps
The blockchain is Available in three different variants 1) Public 2) Private 3) Consortium
Higher cost, slower transactions, small ledger, the risk of error are some disadvantage of using this technology
Dubai- The Smart City, Incent Customer retention, and Blockchain for Humanitarian Aid are the real-life use cases of Blockchain
Bitcoin uses blockchain technology which is not governed by any central authority or banks
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