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About

SHA-256 Hash Generator

Type or paste text and its SHA-256 hash appears as 64 hex characters, or drop a file of any size and it is hashed in your browser without being uploaded. Paste a checksum from a download page, a Docker digest or a line of sha256sum, and the tool says whether it matches.

What it does

  • Text is hashed as its UTF-8 bytes, exactly as typed: a space or line break at the end changes the whole hash.
  • Hex or Base64 can be read as bytes instead of text, for a value that was binary to begin with.
  • The hash in lower-case hex, upper-case hex or Base64, which is 44 characters for SHA-256.
  • A checksum is read with whatever came with it: sha256: or sha256= before it, a file name after it.
  • A row copied from PowerShell’s Get-FileHash works too, its capitals included.
  • HMAC-SHA256 with a secret key, the signature GitHub, Stripe and Slack put on their webhooks.

How to use it

  1. Type the text whose hash you need, or drop the file.
  2. Copy the SHA-256 line, in hex or Base64 as needed.
  3. Paste a checksum you were given to compare it with yours.
  4. For a webhook or an API signature, tick HMAC and enter the secret.

What it does not do

  • Turning a hash back into its text: SHA-256 is one-way, and the only way back is guessing inputs, which is what cracking tools do.
  • Storing passwords as plain SHA-256: it is fast to compute, so guessing is fast too, and passwords want an algorithm made slow on purpose.
  • A folder at once: a folder is not one run of bytes, so hash each file, or a zip of them.

Questions

Why is my hash different from the one sha256sum gives?

Usually a line break. echo adds one at the end, so echo hello | sha256sum hashes hello and a newline. Use echo -n, or press Enter after the text in the box, and the two agree. A space or a capital letter changes the hash just as much.

How long is a SHA-256 hash?

256 bits, which is 32 bytes: 64 characters in hex or 44 in Base64. Every input, one letter or a whole disk image, gives a hash of exactly that length.

Is SHA3-256 the same as SHA-256?

No. SHA3-256 comes from the newer SHA-3 family, built another way, and gives a different hash of the same length; so does SHA-512/256. Paste a checksum of text and every algorithm is tried, and a match outside your list is named.

How do I check a GitHub webhook signature?

Paste the raw request body as text, tick HMAC and enter the webhook’s secret. Then paste the whole X-Hub-Signature-256 header, sha256= and all, where checksums go: the verdict says whether it matches.

Everything here runs in your browser. Nothing you type, paste or open is uploaded, and there is no account and no queue. How that works.

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