Cryptography: Public and Private Key Cryptography

DegreeNotes

What is Cryptography? Explain Public and Private Key Cryptography in Detail

Government College Ludhiana East • E-Commerce — BBA Semester II Prepared by: Jeevansh Manocha

Introduction

In modern E-Commerce systems, businesses exchange highly sensitive information such as passwords, banking details, customer records, and financial transactions through digital networks. Without proper security systems, this information may be stolen, modified, or misused by unauthorized users.

To protect electronic information and ensure secure communication, organizations use cryptography. Cryptography converts readable information into coded form so that only authorized users can access and understand it. It plays an important role in securing online transactions, digital communication, and E-Commerce systems.

Meaning of Cryptography

Cryptography refers to the process of converting readable information into coded or encrypted form to protect it from unauthorized access.

Definition: Cryptography is the science of securing information by converting data into coded form so that only authorized users can access and understand it.

The original readable information is called Plain Text, while the coded information is called Cipher Text.

Objectives of Cryptography

Protect confidentiality of information.
Prevent unauthorized access to data.
Ensure data integrity during transmission.
Provide authentication of users.
Secure online business transactions.

Basic Process of Cryptography

Plain Text

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Encryption Process

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Cipher Text

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Decryption Process

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Original Information

Private Key Cryptography

Private Key Cryptography is also known as Symmetric Key Cryptography. In this method, a single secret key is used for both encryption and decryption of information.

Definition: Private Key Cryptography is a security method in which the same secret key is used for converting plain text into cipher text and converting cipher text back into readable form.

Working of Private Key Cryptography

Plain Text

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Encryption Using Secret Key

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Cipher Text

↓

Decryption Using Same Secret Key

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Readable Information

Advantages of Private Key Cryptography

Fast encryption and decryption process.
Efficient for large amounts of data.
Simple implementation process.

Limitations of Private Key Cryptography

Difficulty in securely sharing the secret key.
Risk of key theft by unauthorized users.
Less secure for large communication networks.

Public Key Cryptography

Public Key Cryptography is also known as Asymmetric Key Cryptography. In this method, two different keys are used — a public key and a private key.

Definition: Public Key Cryptography is a cryptographic system that uses two different keys, one for encryption and another for decryption of information.

Working of Public Key Cryptography

The sender encrypts the information using the receiver’s public key.
The encrypted message is transmitted electronically.
The receiver decrypts the message using a private key.
Only the authorized receiver can access the original information.

Plain Text

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Encryption Using Public Key

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Cipher Text

↓

Decryption Using Private Key

↓

Original Information

Advantages of Public Key Cryptography

Higher level of security.
No need to share private keys publicly.
Supports digital signatures and authentication.
Suitable for internet-based communication systems.

Limitations of Public Key Cryptography

Slower encryption and decryption process.
Complex implementation.
Requires high computational power.

Difference Between Public Key and Private Key Cryptography

Basis	Private Key Cryptography	Public Key Cryptography
Number of Keys	Uses one secret key	Uses two keys
Security Level	Lower security	Higher security
Speed	Faster process	Slower process
Key Sharing	Secret key must be shared	No need to share private key
Complexity	Simple system	Complex system
Main Use	Data encryption	Secure communication and authentication

Importance of Cryptography in E-Commerce

Protects online financial transactions.
Secures customer information.
Prevents cybercrime and hacking.
Supports secure communication systems.
Enhances trust in online business transactions.

Conclusion

Cryptography is an essential security system used in E-Commerce and digital communication to protect sensitive information from unauthorized access. It ensures confidentiality, integrity, authentication, and security in online transactions.

Private key cryptography uses a single secret key for encryption and decryption, while public key cryptography uses two separate keys for higher security. Both methods play an important role in securing electronic communication and maintaining trust in modern digital business systems.