CleanorTools
SHA-1

SHA-1 Hash Generator

Details

How to use SHA-1 Hash Generator

What the tool does, how to run it, and what to expect from the result.

How to generate a SHA-1 hash of text

SHA-1 produces a 160-bit digest, written as 40 hex characters. It remains widespread in legacy systems, in Git object identifiers, and in older API signing schemes, which is why you still need to compute one from time to time even though it should not be chosen for anything new.

The digest is produced by your browser's built-in Web Crypto implementation, running locally. Before you use the output for anything, be clear about whether an attacker could benefit from finding a second input with the same hash, because SHA-1 no longer stops them.

  • Paste the text you want to hash into the input box.
  • Read the 40-character hex digest from the output panel.
  • Use it to compare against a legacy checksum or an existing stored value.
  • Do not use it for a signature, a certificate, or any check an adversary might want to defeat, because SHA-1 collisions have been practical since 2017.
  • If you are choosing a hash for a new system, switch to SHA-256 instead.
Tips

Getting a better result out of SHA-1 Hash Generator

Specific settings and thresholds, not general advice.

  • SHA-1 has been collision-broken since February 2017, when the SHAttered attack produced two different PDFs with the same SHA-1 digest at a cost of about 2 to the power of 63 operations. In 2020 the SHAmbles attack made a chosen-prefix collision practical for roughly 45,000 dollars of rented compute. Do not use SHA-1 for signatures, certificates, or anything where an adversary can influence the input.
  • NIST disallowed SHA-1 for digital signatures back in 2011 and has set out to retire it entirely by the end of 2030. Browsers stopped trusting SHA-1 TLS certificates in 2017. If a system still requires SHA-1, it is a legacy compatibility problem, not a design choice.
  • SHA-1 is still perfectly reasonable for non-adversarial checksums: detecting accidental corruption, generating cache keys, or matching an ETag. Git still identifies objects by SHA-1 (with an added collision-detection step) for exactly that reason. The distinction is whether someone benefits from forging a match.
  • The digest is 160 bits, printed as 40 hex characters. That is 24 characters shorter than SHA-256, which is the fastest way to tell at a glance which algorithm produced a hash you found in a config file.
  • Never use SHA-1 to hash passwords. It is fast, unsalted here, and broken, which is three separate disqualifications. A leaked SHA-1 password table is cracked essentially instantly with an off-the-shelf GPU rig.
Limits

What SHA-1 Hash Generator does not do

The honest boundary, so you do not lose time finding it yourself.

  • It hashes text only. There is no file input, so it cannot check a downloaded archive.
  • It offers no salting and no iteration count, so it is not usable for password storage.
  • It cannot detect a colliding input. A matching SHA-1 digest no longer proves two files are identical, and this tool has no equivalent of Git's collision-detection hardening.
  • It outputs hex only, with no base64 or Base32 form.
Reference

Terms used on this page

Short, plain-language definitions for the formats and settings above.

Privacy & securityHashingHashing turns any input into a fixed-length string of characters using a one-way function — you cannot reverse a hash back into the original data. It is used to store passwords safely, verify files have not changed, and detect duplicates.General
At a glance

Who SHA-1 Hash Generator is for

A quick way to understand who this helps, what it solves, and where it connects next.

Best fit

Developers, security engineers, and anyone verifying data integrity.

Ideal for

Quickly hashing text with SHA-1 without a backend, install, or sign-up.

FAQ

Common questions

Short answers for the questions people usually have before trying a utility like this.

Is the SHA-1 generator free?

Yes. It is completely free to use, with no signup, no account, and no paywall.

Do I need to install anything?

No. It runs in any modern browser on desktop or mobile, with nothing to download and nothing to configure.

Does it stay local?

Yes. Hashing runs entirely in your browser, so the text you hash never leaves your device.

Is SHA-1 broken, and does that matter for what I am doing?

It is broken for collision resistance, which means an attacker can construct two different inputs that hash to the same value. The SHAttered attack demonstrated this with two PDFs in 2017, and chosen-prefix collisions became affordable in 2020. Whether it matters depends entirely on your threat model. If an adversary can supply or influence the content being hashed, and a collision would let them substitute one document for another, SHA-1 is unusable. If you are only detecting accidental corruption in data nobody is attacking, it still works fine.

Why does Git still use SHA-1 if it is broken?

Because Git's use is mostly about identifying content rather than resisting a forger, and because migrating a hash function across every repository in the world is a decade-long project. Git has also hardened itself: since 2017 it ships with collision detection that recognises the SHAttered attack pattern and refuses the object. Work on a SHA-256 object format is underway. It is a good illustration that broken does not mean instantly exploitable everywhere, but it also is not a reason to choose SHA-1 for something new.

What should I use instead of SHA-1?

SHA-256 for general-purpose hashing, which is what almost everything has standardised on. SHA-384 or SHA-512 if you want a larger margin or are on 64-bit hardware where they can be faster. SHA-3 or BLAKE3 if you specifically want a different construction. For passwords, none of these on their own: use Argon2id, scrypt, bcrypt, or PBKDF2 with a salt. For message authentication, HMAC with SHA-256.

How long is a SHA-1 digest and how do I recognise one?

SHA-1 produces 160 bits, shown here as 40 hexadecimal characters. That length is the giveaway: 32 characters is MD5, 40 is SHA-1, 64 is SHA-256, and 128 is SHA-512. If you find a 40-character hex string in a legacy database or a config file, it is almost certainly a SHA-1 digest.

Is the hashing done on a server?

No. It uses your browser's native Web Crypto implementation, so the text is hashed on your machine and nothing is transmitted or stored. Note that browsers only expose crypto.subtle in a secure context, which is why the tool needs the page to be served over HTTPS.

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