Solidity Calculator Smart Contract

A simple calculator implementation in Solidity that performs basic arithmetic operations on the blockchain.

Features

• Addition
• Subtraction
• Multiplication
• Division
• Remainder
• Exponentiation

Usage

The contract can be deployed using Remix IDE (https://remix.ethereum.org/)

License

GPL-3.0

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Custom Hashing and Salting Algorithm

Custom password hashing and salting concepts using JavaScript.

Features

• User registration (Sign Up)
• User authentication (Login)
• Password hashing with salt
• In-memory user storage
• Simple command-line interface

Running the Application

1. Open your web browser
2. Open the browser's developer tools (Usually F12 or right-click -> Inspect)
3. Go to the Console tab
4. Copy and paste the entire code into the console
5. Press Enter to run

Usage

Main Menu Options:

• Enter 1 for Sign Up
• Enter 2 for Login
• Enter 3 to Exit

Sign Up Process:

1. Select option 1
2. Enter desired username
3. Enter password
4. System will confirm successful registration

Login Process:

1. Select option 2
2. Enter username
3. Enter password
4. System will verify credentials and provide feedback

Security Features

1. Password Hashing:

   • Converts passwords into hash values
   • Original passwords are never stored

2. Salt Generation:

   • Unique random salt for each user
   • Prevents rainbow table attacks
   • Makes identical passwords have different hashes

3. Credential Storage:

   • Stores only hashed passwords with salt
   • Username uniqueness enforcement

Code Structure

• generateSalt(): Creates random salt string
• generateHash(): Produces hash from password and salt
• signUp(): Handles user registration
• login(): Manages authentication
• main(): Controls program flow