Unit-1 Foundations of Software Systems and Blockchain

 

Unit 1: Foundations of Software Systems and Blockchain

1. Layers of a Software System

Software systems are typically organized into layers to separate responsibilities, improve maintainability, and allow independent scaling. Common layers include:

  • Presentation Layer: Handles user interface (UI) and user interaction (e.g., web pages, mobile app screens).
  • Application/Business Logic Layer: Contains the core business rules and orchestrates data flow, processing user requests (the "brains" of the application).
  • Data Access Layer (DAL): Provides an interface for the application to interact with data storage, abstracting database complexities.
  • Data Layer: The actual persistent storage for data (e.g., databases, file systems).

This layered approach promotes modularity and makes systems easier to develop, test, and update.

2. Integrity

Integrity in software systems ensures that data is accurate, consistent, and trustworthy throughout its lifecycle, and that processes operate correctly without unauthorized alteration. It means data has not been tampered with or corrupted accidentally or maliciously. Key aspects include data integrity (accuracy of information) and system integrity (system operating as intended). Mechanisms like data validation, access controls, and cryptographic hashing help maintain integrity.

3. A Payment System

A payment system is a network of technologies, rules, and institutions that facilitates the transfer of money between parties for transactions. It involves several components: the Payer (initiator), Payee (recipient), a Payment Instrument (e.g., credit card), a Payment Gateway (authorizes transactions), Acquiring Bank (merchant's bank), Issuing Bank (customer's bank), and Payment Networks (e.g., Visa, Mastercard) that connect them for authorization and settlement. Its purpose is to enable secure and efficient financial exchanges.

4. Types of Software Architecture

Software architecture defines the fundamental structure of a software system. Key types include:

·         Monolithic Architecture: A single, tightly coupled unit for all functionalities. Simple for small apps but hard to scale.

·         Layered (N-Tier) Architecture: Components separated into logical layers (Presentation, Business, Data Access) for better organization and maintainability.

·         Microservices Architecture: Application broken into small, independent services communicating via APIs. Offers high scalability and resilience but adds complexity.

·         Client-Server Architecture: Clients request services from central servers. Centralized control but a single point of failure.

·         Peer-to-Peer (P2P) Architecture: All nodes act as both clients and servers, communicating directly without a central authority. Highly resilient but challenging for consistency and management.

·         Event-Driven Architecture: Components communicate by emitting and reacting to events, promoting loose coupling and scalability.

5. Purpose of the Blockchain

The core purpose of the Blockchain is to create a secure, transparent, and immutable distributed ledger for recording transactions or data. It eliminates the need for a central intermediary by building trust through cryptographic proof and decentralized consensus. This enables verifiable, tamper-resistant record-keeping, fostering a "trustless" environment where participants rely on the system's integrity rather than a single authority.

6. Peer-to-Peer (P2P) System

Definition:

A Peer-to-Peer (P2P) system is a decentralized network where all participants (nodes) are equally privileged, acting as both clients and servers. They communicate directly to share resources and services without a central server.

Architecture:

P2P architectures are decentralized. They can be Unstructured (random connections, easy to build but inefficient search) or Structured (nodes organized for efficient content lookup, more complex). Hybrid models combine central elements with P2P data transfer.

Link between P2P and Blockchain:

The P2P system is the foundational network for Blockchain. Blockchain uses a P2P network to enable decentralized communication, propagate transactions and blocks, and achieve consensus among nodes on the shared, distributed ledger. Without P2P, a blockchain would be a centralized database.

Integrity Threats in P2P Systems:

P2P systems face threats like Data Corruption/Tampering (malicious alteration of shared data), Sybil Attacks (single entity creating multiple fake identities), Free Riding (users consuming resources without contributing), Denial-of-Service (DoS) Attacks, and Eclipse Attacks (isolating a peer from the network). Cryptographic methods and consensus mechanisms help mitigate these, especially in blockchain.

7. Four Ways of Defining Blockchain

Blockchain can be defined as:

1.       A Distributed Ledger Technology (DLT): A decentralized, shared, and immutable database.

2.       A Chain of Cryptographically Linked Blocks: Sequential blocks of data linked by cryptographic hashes, forming an unalterable history.

3.       A Trustless Consensus Mechanism: A system allowing disparate parties to agree on a shared ledger state without a central authority.

4.       A Public, Immutable Record-Keeping System: A transparent and unchangeable system for verifiable data recording.

8. The Purpose of the Blockchain (Re-emphasized)

The central purpose of the Blockchain is to establish a decentralized, trustless, and highly secure system for maintaining an immutable and transparent ledger of transactions or data. It solves the problem of needing an intermediary to verify trust, allowing participants to directly agree on the state of shared information.

9. Blockchain Properties

Key properties that define blockchain technology:

·         Decentralization: No central control; network distributed across multiple nodes.

·         Immutability: Once recorded, data cannot be altered or deleted.

·         Transparency: All transactions are publicly visible (though often pseudonymous).

·         Security: Achieved through strong cryptography and consensus mechanisms.

·         Distributed Ledger: Every node holds a copy of the entire ledger.

·         Consensus: All participants agree on transaction validity and block order.

·         Programmability (Smart Contracts): Ability to execute self-enforcing code on the blockchain.

 

Comments

Post a Comment

Popular posts from this blog

digital marketing ppt-u1

 ppt unit 1-1   download unit 1-2 download unit 2-1 download unit 2-2 download Migrating from Traditional Channels to Digital Channels Migrating from traditional to digital channels can be a significant undertaking for businesses, but it can also lead to significant benefits, such as increased reach, improved customer engagement, and better data-driven decision-making. Here's a breakdown of the process: 1. Define Your Goals and Objectives: What are you hoping to achieve with your digital presence? What specific metrics will you use to measure success? Who is your target audience, and what are their digital habits? 2. Assess Your Current Situation: What are your strengths and weaknesses in terms of digital marketing? What resources do you have available (budget, personnel, technology)? What are the potential risks and challenges of migrating to digital? 3. Choose the Right Digital Channels: Social Media: Which platforms are your target audience most active on? S...
Read more

SOFTWARE

Image
 01 Winrar -64-bit version-623 Download link click- 02 chrome setup Download link click- 03 Turbo-c Download link click-  Dev  C , C ++ 04 typing master 11 Download link click- 05 java software 64-bit version-8 Download link click-               64-bit                                        32-bit        06 Adobe-version-10 Download link click- 07 sublime text -64-version-4 Download link click- 08 python -64-bit-version-3.8.6 -32-bit-version-3.8.10 Download link click- 64-bit                                                  32-bit     09 MS-office 2007 Download link click-    Download link click-wps-office-2020    10 xampp ...
Read more

cn lab

Image
download   01 programs import java.net. * ; import java.io.*; class Ports { public static void main (String [] args) throws Exception { InetAddress h = InetAddress.getLocalHost(); String host =h. getHostName(); String haddr = h. getHostAddress();  System.out.println("\nHost Name: :"+ host);  System.out.println("In Host Address:: "+haddr); for (int i=0; i < 1024; i++) { Socket s=null; try  { s = new Socket ((host), i); System.out.println(" port "+ i + "Active"); } catch (SocketException se) { } catch(Exception e) { System.out.println(" Error...."); } } } } Output:- 02 -program 2 a) import java.io.*; import java.net. *; import java.lang. * ; class chats extends Thread { public static void main (String args []) { try { ServerSocket ss = new ServerSocket (111);  System.out.println ("server ready ");  Socket s = ss.accept (...
Read more

Computer Operations and Performing - D L Unit-1-1

Image
unit-1-1 download   unit-1-2 download   unit-1-3 download  unit-1-1 download  DIGITAL LITERACY syllabus :    Computer      A computer is a programmable electronic device that processes data to perform various tasks. It can store, retrieve, and process information and it is capable of executing a wide range of operations based on instructions provided to it. Computers come in various forms, including personal computers, laptops, servers, and embedded systems. 1.       Central Processing Unit (CPU): Often referred to as the brain of the computer, the CPU performs calculations and executes instructions.   2.       Memory (RAM): Random Access Memory is used to temporarily store data that the CPU needs to access quickly. It is volatile memory, meaning it loses its contents when the power is turned off.   3.       Storage: This includes devices l...
Read more

DBMS Degree Lab Records

Image
  PRACTICAL-I ER-DIAGRAM FOR TRAIN SERVICES  DRAW   ER-DIAGRAM FOR TRAIN SERVICES IN A RAILWAY STATION                              An Entity can be any object, place, person or class. Entity is represented using rectangles. An “ Entity–Relationship Model’’ ( ER- model ) modelling was developed for database design by “ Peter Chen ” and published in a “1976”. An ER- model describes about the inter-related things of interest in a specific domain of knowledge. An ER model is composed of entity types and specifies relationships that can exist between instances of those entity types. RAILWAY MANAGEMENT SYSTEM :-     ·         Railway management System is the computerized system of reserving the seats of train seats in advanced . ·      On-line reservation has made t...
Read more

DS-Record-mca-04) write a program for evaluating a given postfix expression using stack.

Image
    Program:-04   AIM:- write a program for evaluating a given postfix expression using stack. #include<stdio.h> #include<conio.h> int stack[20]; int top = -1; void push(int x) { stack[++top] = x; } int pop() { return stack[top--]; } void main() { char exp[20]; char *e; int n1,n2,n3,num; clrscr(); printf("\nEnter the expression :: "); scanf("%s",exp); e = exp; while(*e != '\0') { if(isdigit(*e)) { num = *e - 48; push(num); } else { n1 = pop(); n2 = pop(); switch(*e) { case '+': { n3 = n1 + n2; break; } case '-': { n3 = n2 - n1; break; } case '*': { ...
Read more

Unit 2: Foundations of Ownership, Security Related Concepts in Blockchain

  Unit 2: Foundations of Ownership, Security Related Concepts in Blockchain Foundations of Ownership In traditional systems, ownership is often documented and verified by centralized authorities (e.g., land registries, banks). In blockchain, ownership is established and proven through cryptographic methods, primarily using public-key cryptography . Public and Private Keys: Each user on a blockchain network has a unique pair of cryptographic keys: a public key and a private key. The public key acts as an address, similar to an account number, visible to everyone. It's used to receive assets or data. The private key is a secret code that grants control over the assets associated with the public key. Only the person possessing the private key can authorize transactions from that address. Digital Signatures: To prove ownership or authorize a transaction, a user digitally "signs" a message or transa...
Read more

Access the Internet to Browse Infromation & E-Mail Operation- D L Unit-2-1

    1. what is internet and what are the applications        The internet is a global network of interconnected computers and other electronic devices that communicate with each other using standardized protocols. It allows users to access and share information, resources, and services across vast distances. The internet facilitates various activities such as communication, research, entertainment, commerce, and much more. Key components of the internet include: 1. **Network Infrastructure** :       This comprises physical and virtual components, including cables, routers, switches, servers, and data centers, that enable the transmission of data across the network. 2. **Protocols** :       Protocols are rules and standards that govern how data is transmitted, routed, and received across the internet. Examples include TCP/IP (Transmission Control Protocol/Internet Protocol), HTTP (Hypertext Transfer Protoc...
Read more

6)what are the various service of internet and protocols ICT-unit-1

Image
The Internet offers a wide range of services that cater to communication, information sharing, entertainment, and business operations. Below are some of the key services provided by the Internet: 1. World Wide Web (WWW) The World Wide Web is a vast collection of interlinked documents, websites, and multimedia content accessible through web browsers like Chrome, Firefox, and Safari. Uses: Accessing websites, reading articles, watching videos, conducting research, and browsing online content. Protocols: Primarily uses HTTP (Hypertext Transfer Protocol) and HTTPS (for secure communication). 2. Email (Electronic Mail) Email allows users to send and receive messages electronically over the Internet. Uses: Communication between individuals or organizations, file sharing, and business correspondence. Protocols: SMTP (Simple Mail Transfer Protocol), IMAP (Internet Message Access Protocol), and POP3 (Post Office Protocol). 3. File Transfer (FTP) The File Transfer Protocol (FTP) allows users to ...
Read more