SHA-256 is the most widely used hash today: a 256-bit fingerprint written as 64 hex characters. It secures TLS certificates, software downloads, Docker image digests, and Bitcoin, and has no known practical attacks.
Where SHA-256 is used
Checksums published next to software downloads.
Docker image digests, such as sha256:2cf24dba…
TLS certificates, code signing, and JSON Web Tokens signed with HS256 or RS256.
Bitcoin's proof of work and transaction IDs.
Checking a download
Click Hash a file and choose the file, then paste the checksum published by the site you downloaded it from into Check against a hash. A match means your copy is identical to the original, byte for byte.