Skip to content
Utiloom

SRI Generator & Verifier

Generate standards-aware SHA-256, SHA-384, and SHA-512 Subresource Integrity metadata from exact local bytes, then verify multi-token policies and export evidence.

LocalNo asset retention

Reviewed July 13, 2026

Guide, examples, and validation Show

About this tool

Create deployment-ready integrity attributes for public scripts and stylesheets while keeping byte scope and runtime checks explicit.

  • Hashes the exact selected bytes with Web Crypto SHA-256, SHA-384, SHA-512, or all three under a 100 MB file limit.
  • Parses bounded multi-token metadata and applies the W3C strongest-supported-algorithm set rule rather than comparing the entire string literally.
  • Creates escaped script or stylesheet markup and versioned JSON evidence while separating local byte verification from deployment, CORS, HTTPS, and browser-load checks.

How to use SRI Generator

Load a local public asset, choose SHA-384 or another supported digest, generate the integrity value, and compare it exactly with the deployed asset bytes.

When this tool is useful

  • Creating an integrity attribute for a versioned public asset.
  • Checking a downloaded asset against an expected SRI value.

Practical tips

  • Prefer immutable versioned asset URLs.
  • Regenerate SRI after every byte change.

Examples you can test

Load an example, compare the result with the expected output, then replace it with your own input.

Generate script integrity

Example input

vendor-4.2.0.min.js with SHA-384

Expected output

sha384-... integrity value and script snippet

SRI complements HTTPS and does not replace origin security.

Validation checklist

  • Hash the exact deployed bytes.
  • Confirm algorithm and Base64 value.
  • Test the final tag in the target page.

Frequently asked questions

How are multiple integrity tokens verified?

The tool evaluates the strongest supported algorithm present in the expected metadata. A match with any valid digest in that strongest algorithm set passes; weaker tokens do not override a stronger mismatch.

Are files uploaded?

No. Exact-byte hashing and verification run locally in this browser.

Does SRI replace HTTPS or prove the deployed response?

No. SRI complements HTTPS, and this tool does not fetch the URL, validate CORS, inspect content negotiation or compression, or perform a browser resource load.

Related tools

Keep the workflow moving

Continue with tools that handle a related input, output, or validation step.

Security

Hash Generator

Create modern text hashes locally.

Local
Security

X.509 Certificate Decoder

Review bounded X.509 fields and supplied chain links.

Local
Security

File Signature & MIME Inspector

Inspect file type consistency and exact byte evidence locally.

Local
Image

Batch Image Optimizer

Resize, convert, and verify multiple images at once.

Local