Subresource Integrity Hash Generator

Hash explicit UTF-8 text with SHA-256, SHA-384, or SHA-512 and emit Base64 Subresource Integrity metadata.

Description

Subresource Integrity metadata combines a hash algorithm with a Base64 digest of resource bytes.

Subresource Integrity metadata combines a hash algorithm with a Base64 digest of resource bytes. Matching depends on exact bytes, including newlines and encoding.^{[1, 2]}

Hash explicit UTF-8 text with SHA-256, SHA-384, or SHA-512 and emit Base64 Subresource Integrity metadata.

When to use Subresource Integrity Hash Generator

Use this tool to hash explicit UTF-8 text with SHA-256, SHA-384, or SHA-512 and emit Base64 Subresource Integrity metadata.

Choose the URL, decoded source text, header value or explicit byte list requested by this tool. Paste the complete relevant input and follow its parsing and encoding conventions.

How to use Subresource Integrity Hash Generator and understand its results

Choose the URL, decoded source text, header value or explicit byte list requested by this tool. Paste the complete relevant input and follow its parsing and encoding conventions.
Enter text, algorithm using the field table and calculation rules, then run the tool.
Read integrity. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
text	Resource content interpreted as UTF-8 text.	string; maximum length: 1000000	Required
algorithm	SRI hash algorithm.	string; one of "sha256", "sha384", "sha512"	Required

Paste the complete resource text and choose sha256, sha384 or sha512. The tool encodes the text as UTF-8, hashes it and emits one integrity token. Whitespace and line endings are not normalized.

integrity=algorithm+'-'+Base64(SHA(UTF8(text)))

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
integrity	Algorithm and Base64 digest.	string; maximum length: 1000000

json

{
  "input": {
    "text": "abc",
    "algorithm": "sha256"
  },
  "output": {
    "integrity": "sha256-ungWv48Bz+pBQUDeXa4iI7ADYaOWF3qctBD/YfIAFa0="
  }
}

Limitations and assumptions

The tool hashes text rather than an arbitrary binary file and does not fetch a resource. It does not verify an existing digest, browser CORS conditions or the safety of the resource's behavior.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Integrity Attribute Parser: Split integrity metadata into supported SHA algorithm tokens, digest text, and options, reporting unsupported or malformed tokens separately. For a complementary task, use ModulepreloadDetector: Extract modulepreload link hints from HTML source without fetching, validating browser support, or resolving their hrefs.

Further background: Subresource Integrity.

References

Subresource Integrity Hash Generator — tool.io
Subresource Integrity — W3C

Similar or alternative tools

Integrity Attribute Parser
Split integrity metadata into supported SHA algorithm tokens, digest text, and options, reporting unsupported or malformed tokens separately.
ModulepreloadDetector
Extract modulepreload link hints from HTML source without fetching, validating browser support, or resolving their hrefs.