SHA-1 Hash Generator — Free Online

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How to use SHA-1 Generator

Enter your text.
Read the 40-character SHA-1 hash.
Use it only for non-security purposes — legacy checksums, Git IDs, deduplication.
For anything security-related, switch to SHA-256 (integrity) or bcrypt (passwords).

What is SHA-1 Generator?

A SHA-1 generator produces the 160-bit (40-hex-character) SHA-1 hash of any input. Once ubiquitous, SHA-1 is now cryptographically broken — researchers demonstrated practical collision attacks (the 2017 "SHATTERED" result produced two different PDFs with the same SHA-1), so it must never be used for security: certificates, signatures, or anything an adversary could attack.

It survives for non-adversarial uses: legacy checksums, Git's internal object IDs (Git uses SHA-1 for addressing, not security — collisions there aren't a practical threat, and Git is transitioning anyway), and verifying files against old published SHA-1 values.

About the SHA-1 Generator

Enter text and get its SHA-1 hash instantly, computed in your browser.

Legitimate uses today: matching legacy checksums — some older software and downloads still publish SHA-1 values; computing yours to compare confirms an accidental-corruption-free transfer (fine, since accidental collisions are astronomically unlikely — only deliberate ones are feasible); Git-related work — understanding or matching commit/object hashes; data deduplication and caching where the input isn't attacker-controlled; and education — learning how hash functions work.

The hard line: for ANY security purpose — password storage (use bcrypt), file-integrity against tampering, digital signatures, certificates, HMAC keys — SHA-1 is unacceptable. Use SHA-256 for integrity and signatures, bcrypt/Argon2 for passwords, HMAC-SHA256 for authentication. If you're reaching for SHA-1 on anything an attacker might touch, that's the signal to switch. Our SHA-256, SHA-512 and HMAC generators cover the secure replacements.

Frequently Asked Questions

Not for security — it's cryptographically broken (practical collisions demonstrated in 2017). Safe only for non-adversarial uses: legacy checksums, Git object IDs, deduplication where no attacker controls the input.

Collisions are feasible — an attacker can craft two different inputs with the same SHA-1, defeating any use that assumes "same hash = same content" (signatures, tamper detection). Accidental collisions remain impossible; deliberate ones are the threat.

For content addressing, not security — collisions between innocent objects are astronomically unlikely, and Git added collision detection plus is transitioning to SHA-256. Its use assumes no adversary, which holds for normal repositories.

SHA-256 for integrity and signatures, bcrypt or Argon2 for passwords, HMAC-SHA256 for message authentication. SHA-1 has a secure successor for every one of its old security jobs.

To detect accidental corruption, yes — if that's the only checksum published. But a matching SHA-1 no longer proves the file wasn't deliberately swapped; prefer the SHA-256 value if the source offers one.