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A browser-based sri hash generator tool. No data sent to server.

📘 How to Use

  1. Upload your script/stylesheet file or paste its content.
  2. Select a hash algorithm (SHA-256, SHA-384, or SHA-512).

SRI Hash Generator

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Subresource Integrity (SRI) Hash Generator｜Secure Your Web Assets

This online tool generates Subresource Integrity (SRI) hashes for your JavaScript and CSS files, helping you prevent malicious file modifications on your website. Simply upload a file or paste its content to create the necessary integrity attribute for your script and link tags. It's an essential utility for developers looking to enhance their site's security and implement a robust Content Security Policy (CSP).

💡 Tool Overview

  • Multiple Hash Algorithms: Supports SHA-256, SHA-384 (recommended default), and SHA-512 to match your security requirements.
  • Flexible Input Methods: Generate a hash by uploading a file, using drag-and-drop, or pasting raw code directly into the text area.
  • Automatic Tag Generation: If you provide the resource URL, the tool automatically generates the complete <script> or <link> tag with the integrity and crossorigin attributes.
  • Client-Side Security: All hashing is performed directly in your browser using the Web Cryptography API. Your files and code are never uploaded or sent to a server.

🧐 Frequently Asked Questions

Q. What is Subresource Integrity (SRI)?

A. SRI is a security feature that enables browsers to verify that resources they fetch (like from a CDN) are delivered without unexpected manipulation. It works by comparing a cryptographic hash of the received file with a hash you provide in the integrity attribute. If the hashes don't match, the browser will refuse to execute the resource, mitigating attacks like compromised CDN files.

Q. Which hash algorithm should I use?

A. The W3C currently recommends using SHA-384 as a minimum. While SHA-256 is still considered secure for this purpose, SHA-384 provides a stronger defense against future computational attacks. SHA-512 offers even greater security but may be overkill for most applications. This tool defaults to SHA-384, striking a good balance between security and performance.

Q. Why is crossorigin="anonymous" required?

A. For the browser to check a resource from a different origin (e.g., a CDN) using SRI, the resource must be served with Cross-Origin Resource Sharing (CORS) headers. The crossorigin="anonymous" attribute tells the browser to make a CORS request without sending user credentials (like cookies). This is a mandatory requirement for SRI to function on third-party assets.

📚 Fun Facts about SRI

Subresource Integrity was standardized to address a significant risk associated with the growing popularity of Content Delivery Networks (CDNs). While CDNs drastically improve performance, they also create a single point of failure; if a CDN is compromised, malicious code could be injected into scripts served to countless websites. SRI provides a decentralized trust mechanism, allowing website owners to ensure the integrity of the assets they load, regardless of the security state of the third-party host.

This tool utilizes the crypto.subtle interface from the Web Cryptography API, a powerful browser feature for performing cryptographic operations. This allows for secure, client-side hash generation without exposing your resource's content to a server, ensuring both privacy and security throughout the process.