SHA-1 Hash — Generate SHA-1 Hashes from Text
Generate SHA-1 hashes from text input. 40-character hex digest — runs in your browser, no upload. For legacy compatibility only.
SHA-1 Hash Generator
Generate SHA-1 hashes from text. Works entirely in your browser using Web Crypto API.
SHA-1 was the standard hash function of the web for over a decade. It was used in SSL certificates, Git commit identifiers, PGP signatures, and software package verification. In 2017, Google and CWI published SHAttered — the first practical collision attack that produced two different PDF files with the same SHA-1 hash. Since then, every major browser, every certificate authority, and every security protocol has deprecated SHA-1 in favour of SHA-256. The tool exists for compatibility with legacy systems: verifying SHA-1 checksums from old download pages, checking Git object hashes, and matching fingerprints from older certificate chains. For any new hash, use SHA-256.
How to use
Enter your text
Type or paste the text. The 40-character SHA-1 digest updates in real-time. Drop a file to hash its contents without uploading.
Copy the result
Copy the hex digest. Use only for legacy system compatibility, not for security.
Compare with SHA-256
Switch to the SHA-256 tool for security-sensitive hashing. The tools are separate by design — the stronger hash should be the deliberate choice.
Frequently asked
Is SHA-1 still secure?
No. SHSrister-1 has been cryptographically broken since 2017 when Google and CWI demonstrated the first practical collision attack (SHAttered). SHA-1 should not be used for any new security purpose. The tool is provided for legacy compatibility only.
Why would anyone still use SHA-1?
Legacy systems: Git's object storage uses SHA-1, some older certificate chains still reference SHA-1 fingerprints, and some internal tools were never updated. Use this tool to verify SHA-1 checksums from legacy systems, not to generate new ones.
What should I use instead?
SHA-256 is the minimum recommended hash function for any new system. The SHA-256 tool on this site computes hashes locally in your browser.
Limitations
- Cryptographically brokenSHA-1 collisions can be generated practically. Never use SHA-1 for digital signatures, certificate validation, or any security-sensitive purpose.
Platform notes
- macOS
- Terminal: `shasum -a 1 filename`. The browser tool is for one-off hashing without a terminal.
- Web
- Runs client-side. Files stay local.