SHA-1 Hash Generator

How to generate a SHA-1 hash

1. Stay on the Text tab and type or paste content — the SHA-1 updates live.
2. Or switch to File and drop in a file to hash its exact bytes.
3. Toggle Uppercase output if you need capitals, then copy the digest.

SHA-1: still common, but broken for security

SHA-1 produces a 160-bit, 40-character hexadecimal digest and remains widely embedded in existing systems: Git uses it to identify commits and objects, many older software packages publish SHA-1 checksums, and plenty of internal tooling still fingerprints files with it. For those non-adversarial jobs — confirming a download is intact, comparing versions, indexing content — SHA-1 works fine. For security, however, it is broken. In 2017 researchers demonstrated a practical collision (the SHAttered attack), producing two different files with the same SHA-1 hash, and the cost of such attacks has only fallen since. That means SHA-1 must not be used for TLS certificates, digital signatures, or any check meant to resist a deliberate attacker; browsers and certificate authorities have already retired it for those purposes. This tool uses the browser's native, audited Web Crypto API to compute SHA-1 locally, so your text and files never leave your device, with no upload, watermark, or signup.

Choosing the right algorithm

When integrity has to hold up against an attacker, move to SHA-256 or SHA-512, which are the current standards. MD5 is faster but even weaker than SHA-1 and only suited to basic checksums. To compare all four algorithms at once, use the full hash generator.

FAQ

Is SHA-1 secure?

No. A practical collision attack against SHA-1 has existed since 2017, so it is broken for security. It is still fine for non-adversarial checksums and for legacy systems like Git that rely on it for identification rather than protection.

Why does Git still use SHA-1?

Git uses SHA-1 to name and address objects, not to defend against attackers, and it has added collision-detection safeguards. For content addressing where no malicious party is crafting inputs, SHA-1 remains practical.

Should I switch from SHA-1 to SHA-256?

For anything security-related, yes. SHA-256 has no known practical collision attacks and is the modern default for signatures, certificates, and download verification.

Is my text or file uploaded?

No. All hashing happens locally in your browser using the Web Crypto API. Nothing is sent to any server.