Network Security Secure hashing algorithm or SHA algorithm and it’s various versions network secure.

Network Security Secure hashing algorithm or SHA algorithm and it’s various versions network secure.

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Here’s a complete guide to the Secure Hashing Algorithm (SHA), including its versions, uses in network security, and importance in cryptography — especially relevant for GATE CSE, Cybersecurity, Networking, and Computer Science Engineering students.

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What is SHA (Secure Hashing Algorithm)?

SHA is a family of cryptographic hash functions designed to ensure data integrity by generating a fixed-size hash (or digest) from input data (message).

Hash Function: Takes an input (of any size) → produces a fixed-length hash value.

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Why is SHA Important in Network Security?

• Data Integrity: Ensures that the data was not tampered with.
• Password Storage: Stores passwords as hash values.
• Digital Signatures: Used in SSL/TLS, HTTPS.
• Blockchain & Cryptography: SHA-256 powers Bitcoin mining.

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SHA Versions Overview

Version	Output Size	Year Introduced	Status	Use Cases
SHA-0	160 bits	1993	Obsolete	Weak security
SHA-1	160 bits	1995	Broken/Retired	Was widely used (SSL, Git, etc.)
SHA-2	224/256/384/512 bits	2001	Secure	Widely used in modern cryptography
SHA-3	224/256/384/512 bits	2025	Secure	Backup standard (based on Keccak)

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SHA-1 (Insecure) – Avoid using!

• Used in SSL certificates, Git, older systems.
• Broken by collision attacks (Google’s SHAttered attack).
• Deprecated by most browsers & organizations.

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SHA-2 Family (Secure, Recommended)

Includes:

• SHA-224
• SHA-256 (most popular)
• SHA-384
• SHA-512

SHA-256:

• Most widely used
• Fixed 256-bit output
• Secure and collision-resistant

Used in:

• HTTPS
• Bitcoin and blockchain
• JWT (JSON Web Tokens)
• Software verification

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SHA-3 (New Standard)

• Based on Keccak algorithm (not Merkle–Damgård like SHA-1/2)
• More resistant to length-extension attacks
• Useful for post-quantum cryptography and IoT devices

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How Hashing Works (Simple Illustration)

Input Message → SHA Algorithm → Unique Hash Code

Example:
Input: "hello"
SHA-256 Output:  
2cf24dba5fb0a... (64 hex characters = 256 bits)

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Properties of a Good Hash Function

1. Deterministic – Same input → same output
2. Fast – Efficient to compute
3. Irreversible – Can’t reverse to get input
4. Collision-resistant – No two inputs → same hash
5. Avalanche effect – Tiny change → big hash change

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Summary Table

Feature	SHA-1	SHA-2 (256/512)	SHA-3
Output Length	160 bits	256–512 bits	256–512 bits
Security	Weak (Broken)	Strong	Strong (Keccak)
Collision Resistance	Low	High	Very High
Applications	Legacy Systems	Modern Crypto	Advanced/Research

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SHA in Exams & Interviews

GATE, UGC NET, and ISRO exams often ask:

• Hash output lengths
• Which version is secure/insecure
• Hash function properties
• Usage in SSL, Blockchain, etc.

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Want More?

I can provide:

• SHA algorithm source code (Python/C++)
• Comparison chart (PDF)
• Practice MCQs (GATE-style)
• Real-world use case analysis (blockchain, auth)

Would you like a diagram, code example, or quiz based on SHA?

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