2026-10-22 · 7 min read
- hash
- checksum
- tooling
The hash page encodes the box as UTF-8 and prints lowercase hex for SHA-256 or SHA-512. It does not trim, it does not add a newline, and it does not print base64. Copy stays disabled while the digest is empty.
An empty box takes a shorter path. The digest is cleared and the empty string is not hashed. Every other value, including a space or the digit 0, is hashed in full.
Do not substitute the empty-string digest
The SHA-256 of zero bytes is e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855. This page leaves the panel blank instead of showing that line. A single space is 36a9e7f1c95b82ffb99743e0c5c4ce95d83c9a430aac59f84ef3cbfab6145068. The digit 0 is 5feceb66ffc86f38d952786c6d696c79c2dbc239dd4e91b46729d73a27fb57e9.
flashman in SHA-256 is 9c35b425f251667dba79f189e990538644b9132e6da3d003979391e3c0f64c7e. The same letters in SHA-512 are d1557ffb04b50111bcd8b524911097ba9c088c624f931f972e3e8a1061dfc49ad94d75526cd3ea52d0d1aee0d684f4821a634fffafa74d0ceb6dfa18cf29cd4f. That is 128 hex characters. The SHA-256 button does not display a prefix of it.
- Leave the box empty when you want no digest.
- Hash a space only when the space is data.
- Match the button to the algorithm in the ticket.
- Compare all 64 or all 128 hex characters.
Include the newline that rode along in the paste
flashman and a line feed is 0fb270e290b457dfe7a7df2a65c073ccf848d44a6a0bc2abb896b99048493848. flashman and CRLF is 05fc1b0a4ef6f462b099c5d21242ed9a0194da3510650842903f1899eee9d9f4. A leading space on flashman is 0d1455aa8c0bc8f69354cc652307d35c2aa0bac90e895c2b7fdb7a3a3c974ead. None of these match the eight-letter digest.
é is UTF-8 C3 A9 and hashes to 4a99557e4033c3539de2eb65472017cad5f9557f7a0625a09f1c3f6e2ba69c4c. 🙂 is F0 9F 99 82 and hashes to d06f1525f791397809f9bc98682b5c13318eca4c3123433467fd4dffda44fd14. Hashing the HTML entity of either character is a hash of different bytes. The Markdown editor is a place those characters can gain a newline or a br in HTML without changing the source you meant to hash.
Keep hex distinct from Base64 and from a file hash
The page never prints a Subresource Integrity token, a colon-separated fingerprint, or uppercase hex. A Base64 string of the same text hashes to something else, because the characters of the encoding are the input. Decode first if the ticket names the original text, then hash.
A file hash from a shell includes whatever newline the file has. Paste the file bytes, or delete the extra newline, before you call the two digests a mismatch. Diff shows the newline. The hash page shows only the hex.
Write the algorithm next to the hex
Copy the digest after the box matches the compared value, including the last newline. Record SHA-256 or SHA-512 in the same note. Switching the button replaces the hex. It does not convert the previous one.
Use the hash tool for the hex, diff to see a hidden newline or space, the Base64 tool to undo an encoding before hashing, and the Markdown editor when the text is prose that may have gained a break. The blank panel means the box was empty. It does not mean the empty-string digest.