৫০তম BCS — ইন্টারনেট ও ওয়েব (HTTPS)

এই পরীক্ষায় এই টপিক থেকে ১টি প্রশ্ন।

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প্রশ্ন ১৮৯: HTTPS কোন বৈশিষ্ট্য HTTP-এর সাথে যোগ করে?

Options: (ক) Security ✓ • (খ) Standardization • (গ) Software • (ঘ) Sense

এক লাইনে

HTTPS = HTTP + Secure (SSL/TLS) — data-in-transit encryption।

HTTP vs HTTPS — পার্থক্য

বৈশিষ্ট্য	HTTP	HTTPS
Full form	HyperText Transfer Protocol	HTTP Secure
Port	80	443
Encryption	নেই (plaintext)	আছে (SSL/TLS)
Speed	তুলনামূলক দ্রুত	কিছুটা ধীর (encryption overhead)
SEO	কম গুরুত্ব	Google ranks higher
Browser indication	http:// (insecure warning)	https:// 🔒 padlock

SSL/TLS — Encryption-এর মস্তিষ্ক

• SSL = Secure Sockets Layer (deprecated since 2015)
• TLS = Transport Layer Security (current standard)
• TLS versions: 1.0 (deprecated), 1.1 (deprecated), 1.2 (widely used), 1.3 (latest)

Working Principle:

1. Browser connects to server
2. Server presents SSL certificate (public key)
3. Browser verifies certificate via CA (Certificate Authority)
4. Symmetric session key exchanged via asymmetric encryption
5. সব subsequent communication encrypted

Common Internet Protocols

Protocol	Full Form	Purpose	Port
HTTP	HyperText Transfer Protocol	Web	80
HTTPS	HTTP Secure	Secure web	443
FTP	File Transfer Protocol	File transfer	21
SFTP	Secure FTP	Secure file transfer	22
SMTP	Simple Mail Transfer Protocol	Sending email	25, 587
POP3	Post Office Protocol v3	Receiving email	110
IMAP	Internet Message Access Protocol	Email (server-stored)	143
DNS	Domain Name System	Name → IP	53
DHCP	Dynamic Host Configuration	Auto IP assign	67, 68
SSH	Secure Shell	Remote login	22
Telnet	Telnet	Remote login (insecure)	23
SNMP	Simple Network Mgmt Protocol	Network management	161
NTP	Network Time Protocol	Time sync	123

URL Anatomy — Web Address

https://www.example.com:443/path/to/page?query=value#fragment
│       │                  │  │           │            │
│       │                  │  │           │            └─ Fragment
│       │                  │  │           └─ Query string
│       │                  │  └─ Path
│       │                  └─ Port (default 443)
│       └─ Domain name
└─ Protocol/Scheme

Domain Name System (DNS)

• Function: domain name (e.g., google.com) → IP address (e.g., 142.250.190.46)
• TLD (Top-Level Domain): .com, .org, .net, .gov, .edu, .bd, .uk
• Country TLD: .bd (Bangladesh), .in (India), .us (USA)
• gTLD: Generic — .com, .org
• DNS Hierarchy: Root → TLD → Authoritative

Web Browser ও Web Server

	Web Browser	Web Server
Role	Client (request)	Server (respond)
Examples	Chrome, Firefox, Safari, Edge	Apache, Nginx, IIS
Renders	HTML, CSS, JavaScript	Stores & serves files

WWW History

Event	Year
ARPANET (Internet predecessor)	1969
Email invented (Ray Tomlinson)	1971
TCP/IP standardized	1983
World Wide Web (Tim Berners-Lee, CERN)	1989
First website	1991
Google search engine	1998
Facebook	2004
YouTube	2005
Twitter	2006
iPhone (mobile web era)	2007

Web 1.0 / 2.0 / 3.0

Web	বৈশিষ্ট্য	যুগ
Web 1.0	Read-only, static pages	1991–2004
Web 2.0	Read-write, user-generated content, social media	2004–present
Web 3.0	Decentralized, blockchain, AI, semantic web	emerging

Common Web Technologies

Tech	Purpose
HTML	structure of web pages
CSS	styling, layout
JavaScript	interactivity, dynamic behavior
AJAX	async data fetch
JSON / XML	data formats
REST API	web service architecture
GraphQL	flexible API query
WebSocket	real-time bidirectional communication

পরীক্ষার শর্টকাট

• HTTPS = HTTP + Secure (SSL/TLS) — পোর্ট 443
• HTTP = 80, HTTPS = 443, FTP = 21, SMTP = 25
• WWW আবিষ্কারক = Tim Berners-Lee (1989, CERN)
• DNS = domain → IP
• URL structure: scheme://domain:port/path?query#fragment

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টপিকটি গভীরে শিখুন

ইন্টারনেট ও ওয়েব — মূল লেকচার শিট — Internet vs WWW পার্থক্য, সব ১৫+ গুরুত্বপূর্ণ Internet protocols (HTTP/HTTPS/FTP/SMTP/POP3/IMAP/SSH/DNS/DHCP), URL anatomy, DNS hierarchy, Web browsers ও Web servers, HTML/CSS/JS basics, Web 1.0/2.0/3.0 evolution, এবং বাংলাদেশের internet ইতিহাস।