Keccak-256 Hash Generator Technical Specification

1. Executive Summary

A high-performance, single-file browser utility designed for Ethereum developers. This tool provides a clean, distraction-free environment to convert text strings into Keccak-256 hexadecimal hashes. The application must function entirely client-side, ensuring maximum security and privacy.

2. Technical Architecture

• Single-File Requirement: All HTML, CSS, and JavaScript must reside in a single file (index.html).
• Dependencies: Use CDN links for the js-sha3 library (for Keccak-256 processing) and Tailwind CSS (for styling).
• Sandboxing: Do not utilize localStorage, sessionStorage, or any persistent storage. The app state must reside solely in memory.
• Performance: Use oninput event listeners to trigger live-hashing, providing real-time feedback as the user types.

3. User Interface (UI) Design

• Aesthetic: Clean, "SaaS" aesthetic using a light-mode color palette (#f8fafc background, #1e293b text). Use soft shadows (shadow-md) on cards.
• Layout Components:
  • Header: Simple title and a brief descriptive sub-headline.
  • Main Input: A large, multi-line <textarea> with a focus state border change (color: blue-500) and clear placeholder text.
  • Output Section: A read-only, selectable text block with a code-font appearance. Include an absolute-positioned "Copy" icon button that triggers a "Copied!" toast notification.
  • Options Bar: A horizontal group of utility buttons (e.g., "Clear", "Copy", "Toggle Encoding" if applicable).

4. Key Functional Features

• Live-Hash Mode: The hash generates instantly upon keystroke, preventing the need for an explicit "Submit" button.
• Copy-to-Clipboard: A reliable clipboard utility function that provides visual feedback upon successful copy (transitioning from an icon to a checkmark).
• Responsive Handling: The layout must stack vertically on mobile (full width) and allow for a balanced, centered layout on desktop (max-width: 600px).
• Zero-Latency Design: Minimize DOM re-renders by updating only the output text content element.

5. Development Constraints

• No External Communication: The app must not make fetch or XMLHttpRequest calls (except for initial asset loading).
• Accessibility: Use proper ARIA labels for all buttons and text inputs to ensure the tool is accessible to screen readers.
• Modals: Use a hidden <div> with fixed positioning to act as a custom modal for "About" or "Usage Instructions" to avoid using alert().
• Transitions: Use transition-all duration-200 ease-in-out for all interactive elements to provide a high-end feel.