Hash Generator (MD5, SHA-256)
Drag & drop a file here, or click to upload
Usage Guide
Hash Generator computes cryptographic hash digests for text strings and files entirely within your browser — no data is ever uploaded. A hash function takes an arbitrary input and produces a fixed-length fingerprint: even a single character change in the input produces a completely different hash. This property makes hashes indispensable for verifying data integrity, checking whether a file has been tampered with, storing passwords securely, and generating unique identifiers. This tool supports the most widely used hash algorithms: MD5 (128-bit, legacy use), SHA-1 (160-bit, legacy), SHA-256 (256-bit, current standard), and SHA-512 (512-bit, maximum strength). MD5 and SHA-1 are computed via the spark-md5 library and a pure-JS implementation respectively, while SHA-256 and SHA-512 use the browser's built-in Web Crypto API (SubtleCrypto.digest) for maximum performance. Text inputs produce hash results immediately as you type, while large files are processed in a background Web Worker so the UI remains responsive. The tool also supports HMAC variants for generating keyed message authentication codes — useful when verifying webhook payloads or API request signatures. All computation is local: you can safely hash confidential documents, passwords, or proprietary file contents without any risk of exposure.
- Choose the hash algorithm — Select MD5, SHA-1, SHA-256, or SHA-512 from the algorithm dropdown. Use SHA-256 or SHA-512 for security-sensitive applications; MD5 and SHA-1 are provided for compatibility with legacy systems that still use them.
- Enter text to hash — Type or paste any text into the input panel. The hash digest appears instantly in the output panel and updates in real time as you modify the input. Even changing a single character produces a completely different hash.
- Hash a file — Drag and drop any file — a document, image, binary, or archive — onto the file-drop zone, or click the upload button to select a file. The file is read locally in the browser; for large files, processing happens in a background Web Worker to keep the interface smooth.
- Compare with a known hash — Paste a known hash value into the "Compare" field below the output. A green checkmark confirms the hashes match (the file or text is authentic); a red cross indicates a mismatch (the data may have been altered).
- Choose output format — Toggle between hexadecimal (lowercase hex, the most common format) and Base64 (useful for HMAC values in HTTP headers and JWT signatures).
- Copy the hash — Click "Copy" to copy the computed hash to your clipboard. Paste it into a security audit report, a comparison field, a Makefile, or an API integration that expects a specific hash format.
Frequently Asked Questions
What is a hash and what is it used for?
A cryptographic hash function takes any input (text or file) and produces a fixed-length fingerprint. Even a single character change produces a completely different hash. Hashes are used to verify file integrity, store passwords securely, and detect data tampering.
Are my files uploaded to a server for hashing?
No. File hashing runs entirely in your browser using the FileReader API (for chunked reading) and a Web Worker (to avoid blocking the UI). Your files never leave your device.
What is the difference between MD5 and SHA-256?
MD5 produces a 128-bit (32 hex character) hash and is fast, but is no longer considered cryptographically secure for security-sensitive uses. SHA-256 produces a 256-bit (64 hex character) hash and is part of the SHA-2 family, which remains secure for integrity verification. For password hashing, use a dedicated KDF like bcrypt or Argon2.
Can I hash large files without the page freezing?
Yes. For large files the tool automatically offloads processing to a Web Worker background thread, so the browser UI remains fully responsive during hashing.
Can I use this tool offline?
2Kit is a Progressive Web App (PWA). After your first visit it is cached and works completely offline.
Technical Implementation
All processing runs entirely in your browser — no data is ever sent to any server. This tool works fully offline as a Progressive Web App (PWA): after the first visit, all pages and assets are cached by a Service Worker and remain available without an internet connection. Your input data never leaves your device, making it safe for sensitive content including API keys, passwords, private configuration, and confidential documents.