Building a Hash Generator with Web Crypto API and a Pure-JS MD5 Fallback

This article provides an in-depth guide on building a real-time hash generator tool using JavaScript's Web Crypto API and implementing the MD5 algorithm from scratch. Here are the key takeaways:

Key Components

1. Web Crypto API:

   • Use crypto.subtle.digest() for SHA algorithms.
   • Implement MD5 yourself due to its legacy status.

2. Algorithm Implementation:

   • MD5: Written in 50 lines of TypeScript, no external dependencies needed.
   • SHA-1, SHA-256, SHA-384, SHA-512: Utilize crypto.subtle.digest() for performance and security.

Real-Time Functionality

• The tool updates the hash output live as you type or drop files.
• Algorithm switching triggers immediate re-computation with current input.

Input Handling

• Normalize all inputs to Uint8Array before hashing.
• Handle text changes efficiently using React state batching and async patterns.

Output Formatting

• Ensure consistent hex padding with .padStart(2, "0").
• Toggle between uppercase and lowercase output formats.

Server-Side Rendering (SSR) Considerations

• Use Next.js's `dynamic

Read the full article at DEV Community

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