Derive keys with PBKDF2
Password-Based Key Derivation Function 2 — configurable iterations and hash. The OWASP-recommended baseline when Argon2 is unavailable. Runs entirely in your browser.
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How PBKDF2 works
PBKDF2 stretches a password through many HMAC iterations of the chosen hash function, producing a key of the requested length.
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Enter password & salt
The salt must be unique per user. 16 random bytes is a reasonable minimum.
Bytes flow through
TextEncoder/TextDecoderfor predictable UTF-8 semantics — emoji, surrogate pairs, and combining marks all encode losslessly.inputUTF-8TextEncoderlosslessliveinput · raw bytespw+salt · UTF-8p / salt
loaded · UTF-8MIME · ready - 02
Pick iterations
OWASP 2024 recommends 600,000+ for SHA-256. Higher is slower for both you and the attacker.
Hash and signature operations call
crypto.subtlefrom the Web Crypto API, so output matches OpenSSL / Node bit-for-bit.costWeb Cryptosubtledeterministicliveiter · options100000 · livetuned
options applied · livelive - 03
Pick output length
32 bytes is typical (matches AES-256 keys).
Options re-run instantly through
useEffect+useMemo— switching URL-safe mode or padding doesn’t re-encode from scratch.lenmemoisedoptionsinstantreactivelen · encoded32 · ready256-bit out
encoded · livelossless - 04
Copy or download
One click to clipboard. Download as .txt.
Copy uses the Async Clipboard API; downloads ship via
Blobwith the appropriate MIME (text/plain,image/png, …) so external tools recognise them.exportclipboardblobMIME-correctclient-sideok · copiedready · doneCopied
shipped · ready to shipsuccess
Encoding without surprises
Always UTF-8 first
Use TextEncoder / TextDecoder for bytes ↔ string conversion. btoa alone breaks on non-ASCII.
URL-safe vs standard Base64
Standard uses +, /, =; URL-safe swaps to -, _, no padding. Don’t mix them.
Hashes aren’t passwords
SHA-256 is fast; that’s good for fingerprints, bad for passwords. Use bcrypt / argon2 for credentials.
Watch padding rules
Some decoders are strict about = padding, others auto-pad. If round-trips fail at exactly 1 or 2 bytes, check padding.
Use Web Crypto for keys
Generate cryptographic keys via crypto.subtle, never Math.random. The latter is predictable.
JWT decode ≠ verify
Decoding a JWT just splits and base64-decodes. Verification needs the issuer’s public key / shared secret.
When to use PBKDF2
When you need a standardised, FIPS-friendly KDF.
Password storage
Stretch + salt + hash before persisting. Output round-trips losslessly with the matching decoder — both run client-side, so end-to-end testing happens in a single tab. Encoding flows through TextEncoder for predictable UTF-8 semantics.
RFC-compliantEncryption keys
Derive AES keys from user passphrases. Web Crypto's subtle.digest produces output that matches OpenSSL, GPG, and Node's crypto module byte-for-byte. That makes the result trustworthy as a content fingerprint, ETag, or integrity check.
OpenSSL-matchedWPA2 PSK
Wi-Fi pre-shared keys use PBKDF2-SHA1. Pairs cleanly with HMAC, JWT, and signed-URL workflows where bit-level correctness matters. The browser's crypto stack is FIPS 140-validated in Chrome and Firefox, so it's production-grade.
lossless1Password / Bitwarden
Vault keys are derived with PBKDF2. Output uses canonical RFC 4648 / 7515 alphabets so curl, openssl, and any standards-compliant decoder accept it as input. URL-safe variants drop padding for tokens that travel in query strings.
byte-identicalFIPS compliance
PBKDF2 is approved in NIST SP 800-132. Heavy hashing runs through useMemo so large inputs don't block typing. PBKDF2, bcrypt, and Argon2 expose configurable cost factors — tune for your threat model, not the default.
spec-gradeTest fixtures
Match RFC 6070 test vectors exactly. Same input plus same options always yields identical bytes. That's the foundation for content-addressed storage (IPFS, Git, S3 ETags) and means the output is safe to commit to fixtures.
production-readyFrequently asked questions
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