SHA-1 Hash Generator
SHA-1 hash of any text as a 40-character hex digest, for matching legacy checksums and old APIs. Hashed locally with Web Crypto. Not for new signatures.
Input
Output
What Is SHA-1 Hashing?
SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function that produces a 160-bit (20-byte) hash value, rendered as a 40-character hexadecimal string. It was designed by the NSA and published by NIST in 1995 as part of the Secure Hash Standard.
While SHA-1 has been deprecated for most security applications due to demonstrated collision attacks, it is still used in legacy systems and for non-security-critical purposes like version control (Git). The algorithm is defined in RFC 3174. This tool computes the SHA-1 hash of your entire input text using the Web Crypto API.
How to Use This Tool
Enter Your Text
Enter the text you want a SHA-1 digest for in the left editor. Sample fills in a test string, and Upload reads the contents of a text file instead.
View the SHA-1 Hash
The SHA-1 hash of your input appears in the right panel and is recalculated with every keystroke.
Copy or Download
The 40-character hex digest can go straight to the clipboard with Copy, or into a text file with Download.
Hash Examples
Here is an example of SHA-1 hashing:
Input Text
SHA-1 Hash Output
Frequently Asked Questions
Is SHA-1 still secure?
No. In 2017, researchers demonstrated the first practical SHA-1 collision in the SHAttered attack. SHA-1 should not be used for digital signatures or certificates. Use SHA-256 or SHA-512 for security-critical applications.
Why was SHA-1 deprecated?
SHA-1 was deprecated because collision attacks became feasible. Google and CWI Amsterdam demonstrated a real-world collision, detailed in this Google Security blog post. Major browsers and certificate authorities have since stopped trusting SHA-1 certificates.
Does the text I hash get uploaded?
No. All hashing is performed locally in your browser using the Web Crypto API. No data ever leaves your machine.
Does Git still use SHA-1?
Yes. Git historically uses SHA-1 for commit and object hashing. However, Git is transitioning to SHA-256 for improved security. The collision resistance is less critical for Git because an attacker would also need write access to the repository.
Related Tools
References: FIPS 180-4 Secure Hash Standard and MDN SubtleCrypto.digest().