PBKDF2 derive

POST /api/pbkdf2-derive2 quota units per call · cache hits free

Stretch a password into a fixed-length key with PBKDF2-HMAC-SHA-256/384/512. Configurable iteration count and output length. Returns the derived key in hex / base64 / base64url.

Stretches a password into a cryptographic key with PBKDF2 — the key-derivation function specified by RFC 8018 §5.2. Internally iterates HMAC-SHAxxx so an attacker has to spend the same effort per guess as your legitimate verifier. Inputs: - `password`: the secret being stretched (UTF-8 by default; hex/base64 if `passwordFormat` is set). - `salt`: per-user random salt (UTF-8/hex/base64). - `iterations`: how many HMAC rounds (OWASP 2023: ≥600_000 for SHA-256, ≥210_000 for SHA-512). - `hash`: underlying hash (SHA-256/384/512). - `bitsLength`: derived-key length in bits (1–4096). - `outputFormat`: hex / base64 / base64url. Pairs naturally with `aes-gcm-encrypt` — use the derived key as the AES key.

Inputs

Name	Type	Default	Description
password*	string	—	Password to stretch.
salt*	string	—	Per-user salt (≥16 bytes recommended).
iterations	number (1000…10000000)	600000	PBKDF2 iteration count. Higher = slower brute-force.
hash	enum (SHA-256 \| SHA-384 \| SHA-512)	"SHA-256"	Underlying HMAC hash.
bitsLength	number (8…4096)	256	Derived-key length in bits.
passwordFormat	enum (text \| hex \| base64)	"text"	Input encoding of `password`.
saltFormat	enum (text \| hex \| base64)	"text"	Input encoding of `salt`.
outputFormat	enum (hex \| base64 \| base64url)	"hex"	Output encoding of the derived key.

Response

Modes: json. Cache: not cacheable.

Every response carries x-cache (HIT / MISS / BYPASS), x-cache-signature (stable across identical inputs), and the rate-limit headers listed below.

Quota & limits

Cost per call	2 units against the 10,000-unit monthly quota. Cache hits are free — only cache misses decrement.
Burst limit	200 requests per rolling minute, shared across all tools.
Max request size	`64 KiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`16 KiB`
Timeout	30s wall clock.
Rate-limit headers	`X-RateLimit-Limit`, `X-RateLimit-Remaining`, `X-RateLimit-Burst-Limit` on every response; `X-Quota-Warning` once 80% of the monthly quota is spent; `Retry-After` on 429s.

Errors

Errors are JSON with an error string; schema failures add a details object (Zod's flattened field errors).

Status	When	Body
400	Input fails the tool's schema (wrong type, missing required field, malformed base64) or the file bytes can't be parsed as the expected format.	{ "error": "invalid inputs", "details": { "fieldErrors": { … } } }
401	Missing or invalid X-Api-Key / X-Account-Id headers (or no session when called from the browser).	{ "error": "unauthorized" }
404	Unknown tool id, or calling /api/* on the website hostname instead of api.xtract.bot.	{ "error": "not found" }
413	Request body over the tool's max request size, or an image header declaring more megapixels than the tool's pixel budget.	{ "error": "…exceeds maxRequestBytes…" }
415	Content-Type isn't application/json on the json-body transport.	{ "error": "unsupported content-type; expected application/json" }
429	Monthly quota or the 200/min burst limit exhausted. Check Retry-After and the X-RateLimit-* headers.	{ "error": "monthly quota exceeded", "monthRemaining": 0, … }
5xx	Conversion engine failure. Safe to retry; if it persists, the input is hitting a bug — please report it.	{ "error": "…" }

Code samples

Built from the default example.


curl -X POST https://api.xtract.bot/api/pbkdf2-derive \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -H "X-Account-Id: $XTRACT_ACCOUNT_ID" \
  -H "X-Api-Key: $XTRACT_API_KEY" \
  -d '{
  "password": "correct horse battery staple",
  "salt": "xtract.bot-demo-salt",
  "iterations": 600000,
  "hash": "SHA-256",
  "bitsLength": 256,
  "outputFormat": "hex"
}'