fipsign-sdk 0.5.2

Post-quantum signing SDK for Python — ML-DSA-65 (NIST FIPS 204)

fipsign-sdk

Post-quantum signing SDK for Python.

Signs and verifies any payload using ML-DSA-65 (NIST FIPS 204) — the post-quantum digital signature standard resistant to Shor's algorithm. Standardized by NIST in August 2024.

Not just for auth. Sign users, orders, documents, devices, events — any entity that needs a tamper-proof, quantum-resistant signature.

---

Install

pip install fipsign-sdk

For async support (httpx-based):

pip install fipsign-sdk[async]

---

Quick start

1. Create a free account at app.fipsign.dev — enter your email, verify the OTP code sent to your inbox.

2. In the dashboard, create a project, then create an API key inside that project. Save the key — it will not be shown again.

3. Use the key in your app:

from fipsign import PQAuth

pq = PQAuth("pqa_your_api_key")

---

sign() — Sign anything

The only required argument is sub — any string identifying the entity you want to sign. All other keyword arguments are stored in the payload and returned on verify. Cost: 1 token.

# Sign a user session
result = pq.sign("user_123", email="[e-mail]", role="admin", expires_in_seconds=3600)
token   = result.token
meta    = result.meta
usage   = result.usage

# Sign an order
result = pq.sign("order_456", amount=299.99, currency="USD", expires_in_seconds=300)

# Sign a document
result = pq.sign("doc_789", hash="sha256:abc...", signed_by="alice")

# Sign a device
result = pq.sign("device_iot_001", firmware="2.1.4")

# Monitor quota and token source
print(f"{usage.freeRemaining} free tokens remaining this month")
print(f"{usage.packRemaining} pack tokens remaining")
print(f"{usage.totalRemaining} total remaining")
print(f"charged from: {meta.source}")  # "free" | "pack" | "free+pack"

sign() response shape

SignResult
  .token   PQToken
               .payload    str   # base64 encoded payload
               .signature  str   # ML-DSA-65 signature
               .algorithm  str   # "ML-DSA-65"
               .issuedAt   int   # Unix timestamp
  .meta    SignMeta
               .algorithm        str
               .standard         str   # "NIST FIPS 204"
               .quantumResistant bool
               .expiresIn        int   # seconds
               .issuedFor        str   # your developer account email
               .projectId        str
               .tokenCost        int   # always 1
               .source           str   # "free" | "pack" | "free+pack"
  .usage   SignUsage
               .freeRemaining  int
               .packRemaining  int
               .totalRemaining int
               .month          str   # e.g. "2026-05"

---

verify() — Verify a token

Never raises. Returns a VerifyResult with valid=False and an error message on any failure.

result = pq.verify(token)

if not result.valid:
    raise PermissionError(result.error)

print(result.payload["sub"])   # "user_123"
print(result.payload["exp"])   # expiry timestamp (Unix)
print(result.payload["iat"])   # issued at timestamp (Unix)
# All custom fields passed to sign() are in payload too

---

revoke() — Revoke a token

Immediately and permanently invalidates a token. Future verify() calls will reject it even if the signature is valid and it hasn't expired. Cost: 1 token.

pq.revoke(token, "user logged out")
pq.revoke(token, "order cancelled")
pq.revoke(token, "suspicious activity detected")

Revoking an already-revoked token returns success without consuming an extra token — the operation is idempotent.

Note: Calling revoke() on an already-expired token raises PQAuthError(code="API_ERROR", status=400).

---

Flask middleware

from flask import Flask, g
from fipsign import PQAuth, flask_middleware

app = Flask(__name__)
pq  = PQAuth("pqa_your_api_key")
auth = flask_middleware(pq)

@app.route("/login", methods=["POST"])
def login():
    import base64, json
    # authenticate user however you like, then:
    result  = pq.sign(user.id, email=user.email, role=user.role, expires_in_seconds=3600)
    encoded = base64.b64encode(json.dumps(result.token.__dict__).encode()).decode()
    return {"token": encoded}

@app.route("/logout", methods=["POST"])
def logout():
    import base64, json
    from flask import request
    header = request.headers.get("Authorization", "")
    if header.startswith("Bearer "):
        from fipsign.types import PQToken
        token = PQToken(**json.loads(base64.b64decode(header[7:]).decode()))
        pq.revoke(token, "user logged out")
    return {"success": True}

@app.route("/api/profile")
@auth
def profile():
    return {"user": g.fipsign_user}

---

FastAPI middleware

from fastapi import FastAPI, Depends
from fipsign import PQAuth, fastapi_middleware

app         = FastAPI()
pq          = PQAuth("pqa_your_api_key")
require_auth = fastapi_middleware(pq)

@app.get("/api/profile")
def profile(user=Depends(require_auth)):
    return {"sub": user["sub"], "role": user.get("role")}

---

Async client

from fipsign.async_client import AsyncPQAuth

async with AsyncPQAuth("pqa_your_api_key") as pq:
    result = await pq.sign("user_123", role="admin", expires_in_seconds=3600)
    v      = await pq.verify(result.token)
    print(v.valid, v.payload["sub"])

---

usage() — Token balance

Free tokens reset on the 1st of each month (UTC). Pack tokens never expire and accumulate across purchases. No token cost.

u = pq.usage()

# Current balance
print(f"Month: {u.current.month}")
print(f"Free:  {u.current.freeRemaining} / {u.current.freeLimit}")
print(f"Used:  {u.current.freeUsed} this month")
print(f"Pack:  {u.current.packRemaining}")
print(f"Total: {u.current.totalRemaining}")
print(f"Account: {u.developer['email']}")

# 6-month history (always 6 entries, months with no activity show 0)
for entry in u.monthlyHistory:
    print(f"{entry.month}: {entry.tokensUsed} used ({entry.fromFree} free + {entry.fromPack} pack)")

# Purchased packs
from datetime import datetime
for pack in u.packs:
    date = datetime.fromtimestamp(pack.purchasedAt).strftime("%Y-%m-%d")
    print(f"{pack.packType}: {pack.tokensPurchased} tokens — {date}")

---

webhooks — Real-time notifications

Events: token.signed · token.rejected · token.revoked · limit.warning · limit.reached

# Register
result = pq.webhooks.register(
    url="https://yourapp.com/webhooks/fipsign",
    events=["limit.warning", "limit.reached", "token.revoked"],
)
print(result.webhook.secret)  # store this — shown only once

# Send a test event
pq.webhooks.test()

# Get current config (secret is never returned after registration)
config = pq.webhooks.get()
if config.webhook is None:
    print("No webhook configured")

# Delete
pq.webhooks.delete()

Verifying incoming webhook requests

from fipsign.middleware import verify_webhook_signature

# Flask
@app.route("/webhooks/fipsign", methods=["POST"])
def webhook():
    from flask import request
    sig = request.headers.get("X-PQAuth-Signature", "")
    if not verify_webhook_signature(request.data, sig, WEBHOOK_SECRET):
        return {"error": "Invalid signature"}, 401
    event = request.json
    if event["event"] == "limit.warning":
        print(f"Warning — {event['data']['freeRemaining']} tokens left")
    return "ok", 200

# FastAPI
from fastapi import Request, HTTPException

@app.post("/webhooks/fipsign")
async def webhook(request: Request):
    body = await request.body()
    sig  = request.headers.get("X-PQAuth-Signature", "")
    if not verify_webhook_signature(body, sig, WEBHOOK_SECRET):
        raise HTTPException(401, detail="Invalid signature")
    event = await request.json()
    return "ok"

---

Error handling

verify() never raises — it returns VerifyResult(valid=False, error="...") on any failure. All other methods raise PQAuthError on failure.

from fipsign import PQAuth, PQAuthError

try:
    result = pq.sign("user_123")
except PQAuthError as err:
    match err.code:
        case "INVALID_API_KEY":    # key missing or doesn't start with pqa_
            ...
        case "API_ERROR":          # server returned an error (check err.status)
            ...
        case "TIMEOUT":            # request exceeded timeout
            ...
        case "NETWORK_ERROR":      # connection failed
            ...
        case "MISSING_SUB":        # sign() called without sub
            ...
    print(err.code, err.message, err.status)

---

Token quota

Every account gets 10,000 free tokens per month, reset on the 1st (UTC). Unused free tokens do not carry over. Additional tokens are available as non-expiring packs, purchased from the dashboard.

Each of these operations costs 1 token: signing, verification, and revocation. Checking usage and fetching the public key are free.

---

Rate limits

300 requests per minute per API key on /sign, /verify, and /revoke. On excess the API returns HTTP 429.

Token quota and rate limits are separate controls:

• "Rate limit exceeded" → back off and retry with exponential backoff
• "Token limit reached" → purchase a pack from the dashboard, retrying won't help

---

Constructor options

pq = PQAuth(
    api_key="pqa_...",                    # required — must start with pqa_
    base_url="https://api.fipsign.dev",   # optional, override for self-hosting
    timeout=10,                            # optional, seconds (default: 10)
)

Option	Type	Default	Description
api_key	str	—	Required. From the dashboard. Raises INVALID_API_KEY immediately if not prefixed with pqa_.
base_url	str	https://api.fipsign.dev	Override for local dev or self-hosted instances.
timeout	float	10	Request timeout in seconds. Raises TIMEOUT on exceeded.
session	requests.Session	—	Custom session (e.g. for proxies or custom TLS).

---

Why ML-DSA-65?

JWT with RS256/ES256 and standard OAuth tokens use ECDSA or RSA — both vulnerable to Shor's algorithm running on a sufficiently powerful quantum computer. ML-DSA-65 is based on the hardness of lattice problems (Module-LWE / Module-SIS), which have no known quantum speedup. It was standardized by NIST in August 2024 as FIPS 204.

---

Integration tests

FIPSIGN_API_KEY=pqa_your_key \
WEBHOOK_URL=https://webhook.site/your-uuid \
WEBHOOK_SITE_TOKEN=your-uuid \
python tests/test_sdk.py

---

Links

• Dashboard: app.fipsign.dev
• Developer guide: fipsign.dev/guide
• API status: api.fipsign.dev/health
• JS SDK: npmjs.com/package/fipsign-sdk
• NIST FIPS 204: csrc.nist.gov/pubs/fips/204/final