SHA-1 Hash Generator: Compute and Verify Checksums

To generate a SHA-1 hash, paste text or drop a file into a SHA-1 generator and read the 40-character hexadecimal digest. The ByteTools SHA-1 Hash Generator uses your browser's native Web Crypto API, so it is fast and standards-correct even for large files, and nothing is ever uploaded.

SHA-1 occupies an interesting middle ground: it is cryptographically broken for collisions, yet it is baked into so much infrastructure — Git most famously — that developers still need to compute and match SHA-1 values regularly.

Why SHA-1 still matters despite being broken

SHA-1 produces a 160-bit fingerprint, written as 40 hex characters. Its collision resistance fell in 2017 with the SHAttered attack, which is why TLS certificates and digital signatures moved to SHA-256. But collision attacks require an adversary deliberately crafting two colliding inputs — they do not affect honest integrity checks. That is why Git still identifies every commit, tree and blob by a SHA-1, and why many package archives publish SHA-1 checksums.

This tool is for developers reproducing Git object IDs, verifying downloads against a published SHA-1, and matching legacy database values that were computed years ago.

How to generate a SHA-1 hash in your browser

1. Select Text or File mode with the tabs.
2. Enter your text or drop a file into the upload area.
3. Read the SHA-1 hash as it appears instantly in the result box.
4. Toggle Uppercase if needed, then click Copy.

How SHA-1 compares to MD5 and SHA-256

Choosing a hash function is mostly about matching the algorithm to the job. This table puts the three most common ones side by side.

Algorithm	Digest length	Security status	Typical use
MD5	128-bit (32 hex)	Broken	Dedup, cache keys
SHA-1	160-bit (40 hex)	Broken for collisions	Git, legacy checksums
SHA-256	256-bit (64 hex)	Secure	Signatures, tamper-proofing

For anything new and security-sensitive, reach for SHA-256. Use SHA-1 only when a system specifically requires it.

Key features and benefits

• Native Web Crypto — fast and standards-correct hashing.
• Text and files — any input type is supported.
• 40-character digest in lowercase or uppercase.
• One-click copy of the result.
• 100% client-side — files never leave your device, even offline.
• Live hashing as you type.

Try the SHA-1 Hash Generator now — it's free and runs entirely in your browser.

Frequently asked questions

Is SHA-1 still secure?

Not for cryptographic purposes. The practical SHAttered collision attack of 2017 means attackers can craft two different files with the same SHA-1, so certificates and signatures moved to SHA-256. It remains fine for non-adversarial integrity checks and legacy compatibility.

Why does Git use SHA-1?

Git uses SHA-1 as a content address to identify commits, trees and blobs — a 2005 design decision. Because collisions are now feasible, Git added a hardened variant that detects known attack patterns and is transitioning toward SHA-256 repositories.

How long is a SHA-1 hash?

Always 160 bits, written as 40 hexadecimal characters. The length never changes with input size — a single word and a 10 GB file both yield 40 hex characters.

What is the difference between SHA-1 and MD5?

Both are legacy hashes, but SHA-1 outputs 160 bits versus MD5's 128 and is somewhat harder to attack. Both are broken for security use; for new systems choose SHA-256 or SHA-512.

Can I verify a file's SHA-1 checksum here?

Yes. Drop the downloaded file in, then compare the resulting 40-character digest with the checksum the publisher lists. If even one character differs, the file was corrupted or altered in transit.

Related free tools

• MD5 Hash Generator — 32-character MD5 digests.
• SHA-256 Hash Generator — secure modern checksums.
• SHA-512 Hash Generator — the strongest SHA-2 digest.
• UUID Generator — generate unique identifiers.

Built by ByteVancer

ByteTools is a free product of ByteVancer, a software and web development studio that builds web apps, SaaS platforms and custom software for businesses. If you have a project in mind, explore ByteVancer's services and hire the team.