100% Client-Side

SHA-1 Hash Generator

Generate SHA-1 hashes — for legacy compatibility checks

Free Client-Side No Login No Storage
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SHA-256 Hash Generator Generate SHA-256 cryptographic hashes instantly — Hex or Base64 output SHA-512 Hash Generator Generate SHA-512 cryptographic hashes — stronger than SHA-256 MD5 Hash Generator Generate MD5 checksums — fast, widely supported, not for passwords

How to Use the SHA-1 Hash Generator

  1. Enter or paste text into the input field.
  2. Select Hex or Base64 output format.
  3. Click Generate Hash to compute the SHA-1 digest.

SHA-1 produces a 160-bit (20-byte) hash. Warning: SHA-1 is deprecated for security use due to known collision attacks. Use it only for legacy compatibility or checksums.

What is SHA-1 Hashing?

SHA-1 (Secure Hash Algorithm 1) is a 160-bit cryptographic hash function standardized by NIST in 1995. It generates a 40-character hexadecimal digest. While historically ubiquitous in SSL certificates and Git version control, SHA-1 is now deprecated for security purposes due to known collision vulnerabilities demonstrated by researchers in the SHAttered and Shambles attacks.

Common Uses

  • Validating legacy Git object identifiers (SHA-1 commit hashes)
  • Verifying checksums of older archival packages and legacy software
  • Educational study of cryptographic collision vulnerabilities and hash functions
  • Interoperating with legacy systems that mandate 160-bit digest verification

Frequently Asked Questions

Is SHA-1 safe for passwords or digital certificates?

No. NIST officially deprecated SHA-1 in 2011 and banned its use in digital signatures. Collisions can now be generated with modest cloud computing budgets. Modern systems should use SHA-256 or SHA-3.

Why does Git still use SHA-1?

Git historically used SHA-1 as a content-addressable identifier rather than a pure security barrier. Git has since introduced hardened SHA-1 and is transitioning to SHA-256 for modern repositories.

Can I use SHA-1 for non-security checksums?

Yes. If you only need to verify that a file was not corrupted by network transmission or disk decay (and malicious tampering is not a concern), SHA-1 remains an effective and fast checksum.

Notes from this implementation

Why this page still exists

SHA-1 is a 160-bit hash (40 hex characters). Practical collisions have been public since SHAttered in 2017. Git still addresses objects with SHA-1, and some old certificate chains and file manifests still print it. This page is for checking those legacy strings, not for choosing a hash on a new design.

Vector

hello
aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d

A collision means two different files can share one SHA-1. It does not mean you can invert a digest back to the original text. For a download check against a vendor who only publishes SHA-1, prefer to find a SHA-256 alongside it. If the vendor publishes only SHA-1, treat a match as “not randomly corrupted,” not as “authentic.”

The MD5 password note on the blog applies here too: a fast hash with no salt is not a password store. SHA-1 is faster to attack than SHA-256 and already has chosen-prefix collisions.