CycleCore PQ — Python SDK

Post-quantum cryptography as a service. Dilithium3 signing, Kyber768 encryption, AES-256-GCM — one API call. NIST-standardized (FIPS 204, FIPS 203, FIPS 197).

Try it now — no signup, no install, no API key.

Install

pip install cyclecore-pq

Quick Start

from cyclecore_pq import CycleCoreClient

client = CycleCoreClient("pq_live_YOUR_KEY")

# Sign a message with Dilithium3 (FIPS 204)
result = client.sign(b"hello world")
print(f"Signature: {result.signature[:40]}...")
print(f"Latency: {result.latency_us:.1f} us")

# Verify
verified = client.verify(b"hello world", result.signature_bytes)
print(f"Valid: {verified.valid}")  # True

# Encrypt with Kyber768 + AES-256-GCM (FIPS 203/197)
encrypted = client.encrypt(b"sensitive data")
decrypted = client.decrypt(encrypted.ciphertext_bytes)
print(decrypted.plaintext_bytes)  # b"sensitive data"

Get a free API key (1,000 ops/day): Register

Zero-Exposure Signing (ZES)

Sign and verify without exposing plaintext to the API. Your data is hashed client-side with SHAKE-256 — the API only sees a 32-byte digest.

from cyclecore_pq import CycleCoreClient, zes_sign, zes_verify

client = CycleCoreClient("pq_live_YOUR_KEY")

# API never sees your original data — only a SHAKE-256 hash
result = zes_sign(client, b"sensitive medical record")
print(f"Signature: {result.signature[:40]}...")

# Verify (also uses ZES — hashes before checking)
verified = zes_verify(client, b"sensitive medical record", result.signature_bytes)
print(f"Valid: {verified.valid}")  # True

Batch signing — send 32 bytes per item instead of full payloads:

from cyclecore_pq import zes_sign_batch

records = [record.encode() for record in patient_records]
batch = zes_sign_batch(client, records)  # up to 1,000

When to use ZES:

• Regulated data (HIPAA, PCI, GDPR) — sign without sending PII to a third party
• Large documents — send 32 bytes instead of 10MB
• Zero-trust architectures — use CycleCore without trusting us with your content
• Blockchain/DeFi — sign transaction digests without exposing full tx data

ZES uses SHAKE-256 (recommended for Dilithium synergy). The double-hash chain (SHAKE-256 client, SHA-256 server, Dilithium3 sign) is cryptographically sound and does not weaken NIST security properties. See examples/zes_privacy_signing.py for full examples.

Note: ZES applies to signing and verification only. Encryption requires actual plaintext.

Async

from cyclecore_pq import AsyncCycleCoreClient

async with AsyncCycleCoreClient("pq_live_YOUR_KEY") as client:
    result = await client.sign(b"hello world")

Methods

Errors

from cyclecore_pq import AuthenticationError, RateLimitError, ValidationError

try:
    result = client.sign(b"hello")
except AuthenticationError:
    print("Invalid API key")
except RateLimitError:
    print("Rate limit exceeded")
except ValidationError:
    print("Bad request")

Links

• Live Demo — try PQ crypto in your browser
• API Docs — interactive Swagger UI
• Homepage