# CooL by Northwind Cipher

> CooL is the black box for AI: a developer SDK, CLI and offline verifier that capture every change to an AI system (prompts, models, policies, tool grants), seal each one as a post-quantum signed, tamper-evident receipt in an append-only transparency log, and let anyone verify it offline, with no account and no trust in the vendor. Hardware attestation runs on Intel TDX through Phala dstack.

Northwind Cipher Pvt. Ltd. (also written NorthWind Cipher; Coimbatore, India; https://northwindcipher.com) builds CooL. Northwind Cipher is a member of the NVIDIA Inception Program.

## Key facts

- Install: `npm i -g cool-nwc` (Node.js 20+). Source: https://github.com/Northwind-Cipher/cool-sdk (BUSL-1.1; cool-nwc 3.0.0 and earlier Apache-2.0).
- Signatures: hybrid ML-DSA-65 (FIPS 204) + Ed25519 over canonical CBOR; SHA-256 commitments; sensitive values are salted hashes, never plaintext.
- Log: RFC 6962 Merkle transparency log with signed tree heads, inclusion and consistency proofs.
- Seven verification domains, reported separately: binding, signature, inclusion, consistency, witness, attestation, enclave.
- All seven verified on real Intel TDX hardware on Phala Cloud: raw TDX quotes verified by Phala's attestation service and a local dcap-qvl check, MRTD/RTMR0-3 pinned, report_data bound to the signing key, an 11-row tamper matrix, and a workload-change test. Evidence: https://github.com/Northwind-Cipher/cool-sdk/blob/main/artifacts/closure-verification-matrix.md
- Stated limits: CPU Intel TDX only (no GPU attestation claimed); the witness ran in a separate CVM under the same account (independent operation not claimed); no SOC 2, ISO 27001 or HIPAA certification is held.
- CooL does not host or run models. It is provider-neutral and records what changed.
- Ecosystem: NVIDIA Inception (member); Phala provides the confidential-compute infrastructure CooL runs on; working towards a collaboration with Edgeless Systems (WirtschaftsWoche Best of Technology 2026, makers of Contrast).

## Pages

- [Home](https://northwindcipher.com/): product overview, ecosystem (NVIDIA Inception, Phala, Edgeless Systems), verification domains, founders, FAQ
- [Pricing](https://northwindcipher.com/pricing): free developer tier, plans, usage pricing; verifying is always free
- [Studio](https://northwindcipher.com/studio): live in-browser change record you can seal, verify and tamper with
- [Security model](https://northwindcipher.com/security): threat model, trust boundaries, what is and is not proven
- [Readiness](https://northwindcipher.com/security/readiness): the public gate ladder
- [How CooL works](https://northwindcipher.com/technology)
- [Architecture](https://northwindcipher.com/architecture)
- [Verify a record](https://northwindcipher.com/verify)
- [Demo](https://northwindcipher.com/demo)
- [Docs](https://northwindcipher.com/docs): [Quickstart](https://northwindcipher.com/docs/quickstart), [Verify it yourself](https://northwindcipher.com/docs/verify-it-yourself), [Receipt format](https://northwindcipher.com/docs/receipt-format), [Threat model](https://northwindcipher.com/docs/threat-model)

## Founders

- Pranauv Shrinaath S, Founder & CEO (post-quantum cryptography): pranauvshrinaath@northwindcipher.com, https://github.com/KenidoesCode
- Kailosh Kalimuthu, Co-Founder & CTO (trusted execution environments, AI inference): kailoshkalimuthu@northwindcipher.com, https://github.com/Sk1zmo

## Contact

- Book a call: https://cal.com/coolnwc
- Package: https://www.npmjs.com/package/cool-nwc