SHA1 Hash Generator

Generating a SHA1 hash

This tool computes the SHA1 hash of whatever you type or paste. A hash is a fixed-length string (40 characters) derived from the content, and it changes completely if the input changes even by one character.

SHA1 is no longer recommended for new security work, since practical attacks producing identical values are known. It is still widely used for simple comparisons.

How to use it

Paste your text into the input field. The SHA1 value is computed and can then be copied.

Watch out for stray spaces or a trailing newline: they count as part of the input and will produce a different value.

What hashes are used for

For checking whether two files or texts match without comparing them in full.

In older systems and version control, SHA1 is entrenched as an identifier for content.

What hashes do not do

For signatures and integrity guarantees, use SHA256 or a newer algorithm instead.

SHA1 is also unsuitable as a password algorithm because it computes very quickly.

Frequently asked questions

Can the original text be recovered from a SHA1 value?

No. Hashing is one-way: it derives a value from the input, not the other way round. Short or very common inputs can still be guessed by trial and error, however.

Why does the same input always give the same value?

That is intentional. Identical input always yields an identical hash, and that property is exactly what makes hashes useful for comparing two pieces of content.

Does my input leave the device?

Processing runs in the browser. Even so, avoid pasting confidential material if you would rather it were not processed at all.