SHA-1 Hash Generator

How to Use the SHA-1 Hash Generator

The SHA-1 Hash Generator produces a 160-bit (40-character hexadecimal) hash from text or file input. While SHA-1 has been deprecated for security-critical applications, it remains useful for checksums, Git commit hashes, and legacy system compatibility.

Deprecation Warning

SHA-1 is considered cryptographically broken since Google demonstrated a practical collision attack (SHAttered) in 2017. Major browsers and certificate authorities no longer accept SHA-1 for SSL/TLS certificates. For new projects, use SHA-256 or SHA-512 instead.

Text and File Hashing

Enter text or drag a file to generate its SHA-1 hash. The computation runs entirely in your browser using the Web Crypto API. Despite deprecation for security use, SHA-1 remains fast and widely supported.

Where SHA-1 Is Still Used

Git uses SHA-1 for commit identifiers. Many legacy systems and older APIs still require SHA-1 checksums. It is also used in some non-cryptographic deduplication and caching systems where collision resistance is not critical.

Frequently Asked Questions

Q: Why is SHA-1 deprecated?

A: In 2017, researchers from Google and CWI Amsterdam demonstrated a practical collision attack called SHAttered, proving that two different PDF files could produce the same SHA-1 hash. This makes SHA-1 unsuitable for digital signatures and certificates.

Q: Can I still use SHA-1 for checksums?

A: For non-security checksums like verifying file transfers where an attacker is not actively trying to create collisions, SHA-1 is still functional. However, SHA-256 is recommended as a better default choice.

Q: What is the length of a SHA-1 hash?

A: SHA-1 produces a 160-bit hash, displayed as a 40-character hexadecimal string.