SHA-1 generator

Be the first to rate this tool

Processed instantly and never stored — we keep no copy of your input.

SHA-1 in Depth

SHA-1 (1995) produces a 160-bit digest and powered the early secure web: TLS certificates, Git object IDs, and software signatures all relied on it. For a decade it was simply "the hash."

The SHAttered Moment

In 2017, Google's SHAttered project produced two different PDFs with the same SHA-1 hash after ~110 GPU-years of computation — expensive, but practical for well-funded attackers. Browsers had already begun distrusting SHA-1 certificates; afterward, everyone did.

What Remains

Git still uses SHA-1 for addressing (with collision-detection mitigations), and legacy systems verify old signatures with it. Generate SHA-1 here for compatibility — but sign nothing new with it, and migrate anything important to SHA-256.

How to Use the SHA-1 Hash Generator

SHA-1 produces a 160-bit digest that was once the internet standard — it is now considered broken for security, but this tool is useful for verifying legacy checksums and old Git object IDs.

Paste the string to hash — SHA-1 is broken for security but still appears in legacy Git-style identifiers.
Click the hash button to compute the 160-bit SHA-1 digest.
Copy the 40-character hexadecimal result to compare against legacy checksums or historical records.

Example

Hashing the word hello with SHA-1 always produces aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d — exactly 40 hexadecimal characters, the same on every run.

Frequently Asked Questions

Is SHA-1 still safe to use?
No — not for security. The 2017 SHAttered attack demonstrated practical collisions, and attacks have only improved since. Use it only for compatibility with legacy data, never for signatures or integrity you rely on.

Why do I still see SHA-1 everywhere?
Git uses SHA-1 object IDs, and countless old downloads, ISOs and archives publish SHA-1 checksums. Those are compatibility uses — new systems should migrate to SHA-256.

What replaced SHA-1?
SHA-256 is the standard replacement for general hashing, with SHA-3-256 as the modern alternative built on a completely different design.