MD5, SHA-1/256/512 from text or files. Stays in your browser.
SHA-1/256/512 use the browser's native SubtleCrypto API. MD5 is computed with a self-contained implementation (SubtleCrypto doesn't support MD5 - by design; it's cryptographically broken). Nothing is uploaded; all hashing happens locally.
A cryptographic hash function takes input of any size and produces a fixed-length output (the "digest") in a deterministic, one-way process. The same input always produces the same hash. A different input - even a one-character difference - produces a completely different hash. You can't reverse the hash to recover the original input.
SHA-256 and SHA-512 are current standard - used in TLS certificates, code signing, and blockchain systems. SHA-1 has known collision vulnerabilities and should not be used for security purposes, but it's still common as a non-security checksum (Git commit IDs, for instance).
MD5 is cryptographically broken - collisions are feasible and have been demonstrated in practice. Don't use it for passwords, certificates, or anything security-critical. It survives because it's fast, short, and ubiquitous as a non-cryptographic checksum: verifying file integrity over a trusted channel, legacy database fingerprinting, that sort of thing.
This tool computes all four simultaneously so you can provide whatever format a downstream system expects. File hashing is particularly useful for verifying that a download wasn't corrupted or tampered with - compare the hash against the one published by the software author.
Privacy: files are read via the FileReader API, processed in memory in your browser, and immediately discarded. They are not uploaded to any server. bitmods sees nothing.