CHECKSUM

When you download an app, an ISO, or an installer, the source often publishes a hash (a long fingerprint) so you can confirm the file arrived exactly as intended and was not swapped or corrupted. CHECKSUM computes that fingerprint from your file, right in your browser, and checks it against the one you were given. The file never leaves your device. Computing a hash is free; checking it against an expected value and choosing other algorithms need a Sovereign pass.

CHECKSUM runs entirely in your browser using its built-in cryptography and never uploads your file. A matching hash means the file is byte-for-byte the one the source published; a mismatch means it was changed, corrupted, or you are comparing against the wrong value. A hash confirms integrity, not safety: it tells you the file is unchanged from the source, so only compare against a hash from a source you trust.