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SHA-1 Hash Generator - Generate SHA-1 Hashes Online

SHA-1 Hash
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All Hash Algorithms

About the SHA-1 Hash Generator

SHA-1 is one of the most historically important hash functions in computing. Published by NIST in 1995, it produces a 160-bit digest (40 hex characters) and became the backbone of SSL/TLS certificates, Git version control, and countless integrity-verification systems for over two decades.

This tool computes SHA-1 hashes using the Web Crypto API built into your browser. All processing happens locally, and no data leaves your machine.

How to Use the SHA-1 Generator

Paste or type your text into the input field. The SHA-1 hash appears instantly below. Click the copy button to grab the 40-character hex digest for use in scripts, configuration files, or comparison checks.

SHA-1 in Practice

Git identifies every object (commit, tree, blob, tag) by its SHA-1 hash. When you run git log --oneline, the short strings you see are abbreviated SHA-1 digests. While Git is gradually adding SHA-256 support, SHA-1 remains the default object format.

SHA-1 is also used in HMAC-SHA1 for OAuth 1.0 signatures and in some legacy TOTP (time-based one-time password) implementations. While newer systems prefer SHA-256, many existing integrations still require SHA-1 compatibility.

Security Status

SHA-1 was proven vulnerable to collision attacks in the 2017 SHAttered research by Google and CWI Amsterdam. All major browsers and certificate authorities stopped trusting SHA-1 signatures that year. For any new security-sensitive application, use SHA-256 or SHA-512 instead. SHA-1 remains acceptable for non-security identifiers like Git object hashes and content-addressable storage keys.

Frequently Asked Questions

What is SHA-1?
SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function that produces a 160-bit (20-byte) hash value, typically rendered as a 40-character hexadecimal string. It was designed by the NSA and published by NIST in 1995.
Is SHA-1 still secure?
SHA-1 is no longer considered collision-resistant. Google and CWI Amsterdam demonstrated a practical collision (SHAttered) in 2017. Major browsers and certificate authorities stopped accepting SHA-1 certificates in 2017. For new projects, SHA-256 is the recommended minimum.
Why does Git use SHA-1?
Git uses SHA-1 to identify commits, trees, blobs, and tags. When Git was designed in 2005, SHA-1 was still considered secure. Git is gradually migrating to SHA-256 (available as an experimental option since Git 2.29), but SHA-1 remains the default for backward compatibility.
How long is a SHA-1 hash?
A SHA-1 hash is always 160 bits (20 bytes) long, displayed as a 40-character hexadecimal string. This is longer than MD5 (128 bits / 32 characters) but shorter than SHA-256 (256 bits / 64 characters).