CryptoBox: RSA, DSA, and AES Encryption

Project Overview

CryptoBox is a Python-based cryptographic tool that implements three powerful encryption algorithms:

• RSA (Rivest–Shamir–Adleman): An asymmetric encryption algorithm that uses public and private keys.
• DSA (Digital Signature Algorithm): Used to create digital signatures for verifying the authenticity and integrity of messages.
• AES (Advanced Encryption Standard): A symmetric encryption algorithm for encrypting and decrypting data using a shared secret key.

This project allows users to encrypt and decrypt messages using RSA, DSA, and AES, as well as sign and verify messages using DSA.

Features

• RSA Encryption/Decryption: Securely encrypt and decrypt messages using public/private key pairs.
• DSA Signing/Verification: Create and verify digital signatures to ensure the authenticity and integrity of messages.
• AES Encryption/Decryption: Encrypt and decrypt data using a shared secret key.

Requirements

To use this tool, you need Python 3 and the pycryptodome library installed on your system. You can install it using the following command:

pip install pycryptodome

How to Use

Clone the Repository If you have not already, clone the repository using the following command:

git clone https://github.com/Dharan10/Cryptbox.git
cd CryptoBox

Run the Script

To start using CryptoBox, you can run the Python script (text_encrypter.py):

python3 text_encrypter.py

Enter Text for Encryption/Signing After running the script, it will prompt you to enter the text you want to encrypt or sign.

Enter a text to perform Encryption:

Once you enter the text, the tool will:

Encrypt the text using RSA (asymmetric encryption).
Encrypt the text using AES (symmetric encryption).
Sign the text using DSA (digital signature).
Verify the signature using DSA.

Example

Cryptographic Algorithms: RSA, DSA, and AES

1. RSA (Rivest–Shamir–Adleman)

RSA is an asymmetric encryption algorithm, meaning it uses a pair of keys:

• Public Key: For encryption.
• Private Key: For decryption.

How RSA Works:

1. A message is encrypted using the recipient's public key.
2. The recipient decrypts it using their private key.

Use Case:

• Secure data transmission, such as exchanging sensitive information between parties.

Example:

Encryption:

• Public key encrypts the message: Hello.
• Result: Ciphertext (garbled, secure form).

Decryption:

• Private key decrypts the ciphertext back to: Hello.

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2. DSA (Digital Signature Algorithm)

DSA is used for digital signatures to:

• Prove the authenticity of a message.
• Ensure the message has not been altered (integrity).

How DSA Works:

1. The sender generates a digital signature for the message using their private key.
2. The recipient verifies the signature using the sender’s public key.

Use Case:

• Signing documents, software distribution, or digital certificates.

Example:

Signing:

• Private key signs the message: Transaction Approved.
• Result: A unique signature attached to the message.

Verification:

• Public key verifies that the signature is valid and belongs to the sender.

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3. AES (Advanced Encryption Standard)

AES is a symmetric encryption algorithm, meaning it uses a single key for:

• Encryption: Convert plaintext to ciphertext.
• Decryption: Convert ciphertext back to plaintext.

How AES Works:

1. The same secret key encrypts and decrypts the message.
2. The key must be shared securely between the sender and receiver.

Use Case:

• Encrypting data at rest (stored data) or in transit (e.g., Wi-Fi security).

Example:

Encryption:

• Secret key encrypts: Confidential Info.
• Result: Ciphertext (unreadable form).

Decryption:

• Same secret key decrypts the ciphertext back to: Confidential Info.

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Comparison Table:

Feature	RSA	DSA	AES
Type	Asymmetric encryption	Digital signatures	Symmetric encryption
Keys	Public/Private	Private for signing, Public for verifying	Single key for encryption/decryption
Speed	Slower	Faster	Fastest
Use Case	Secure data transmission	Authenticity and Integrity	Data encryption

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Practical Example:

Let’s say Alice wants to send a secret message and verify her identity:

Encryption (RSA):

1. Alice uses Bob’s public key to encrypt: Meet me at 5 PM.
2. Bob decrypts it using his private key.

Digital Signature (DSA):

1. Alice signs the message with her private key.
2. Bob verifies Alice’s identity using her public key.

Encryption (AES):

1. Alice and Bob agree on a shared secret key.
2. Alice encrypts the message with the key.
3. Bob decrypts it using the same key.

This ensures confidentiality (AES), authentication (DSA), and secure communication (RSA).