Hash & encoding lab

When to hash, when to encode, when to do neither

Hash when you need integrity or commitment without disclosure: storing a check that a file was unchanged, or comparing a candidate against a known value without keeping the raw candidate. Hash is also the primitive behind password k-anonymity proofs where only a fragment of a hash leaves the device. It is not encryption: anyone with the candidate can confirm equality, and short or low-entropy inputs are trivially guessable by enumerating candidates.

Encode when a transport requires a character set, URLs permitting only ASCII, email carrying binary as printable text, or APIs accepting data inline. Base64 expands size by roughly a third; percent encoding expands only the characters that would break the container. Neither provides secrecy, only transport safety.

Neither primitive replaces encryption. If something must be private, encrypt it with a key whose compromise you can revoke; if you need a password hash for verification, use a password-oriented function like Argon2 or scrypt, not a plain fingerprint hash.

What the panel computes

For hashes, the panel exposes SHA-1, SHA-256, SHA-384 and SHA-512. SHA-1 is offered for interoperability with existing systems that still index SHA-1 digests, but for integrity of new data prefer SHA-256 or stronger. Missing from the list is MD5, which the Web Crypto API deliberately omits because its collision resistance is broken.

For encodings, the panel toggles between raw text, Base64 and URL percent encoding, matching what developers typically juggle when debugging API payloads or redirect parameters. Copy buttons preserve the exact output formatting you see, without stray newlines.

• Hash outputs are shown in lowercase hex; copy produces that hex verbatim.
• Base64 strict padding and URL-safe variants matter when pasting into header values, normalize according to the destination's spec.
• Percent encoding here follows encodeURIComponent semantics, which encodes all characters that are not safe in a query component.

A short practical guide

Debug identity issues by hashing a stable candidate locally and comparing against published digests. Transport a small binary by encoding it to Base64 for logging, then decoding on the other side before use. Keep the lab open as a scratch pad; its value is that it is offline, immediate and not shared with any service, so secrets that should not be pasted into a remote tool remain in your process while you transform them.