# BA | Stamp

> Legal-grade blockchain timestamps. Prove the existence and integrity of any document at a precise moment in time, with evidentiary value admissible across 30+ jurisdictions under eIDAS 2.0, Art. 2712 c.c. (Italy), FRE 901(b)(9) (US), and equivalent frameworks worldwide.

BA | Stamp is a Software-as-a-Service product operated by Aletheia Tech Ltd (UK). Documents are SHA-256 hashed client-side (the file never leaves the user's browser); hashes are aggregated into a Merkle tree and anchored on the Polygon blockchain (primary) and Bitcoin via OpenTimestamps (secondary). Each stamped document gets a self-verifying PDF certificate with the full verification procedure, Merkle inclusion proof, and jurisdiction-specific legal framing.

BA | Stamp issues **non-qualified electronic timestamps under eIDAS Art. 41** — admissible as electronic evidence but not equivalent to a qualified timestamp under Art. 42 (which requires issuance by an accredited QTSP).

## Key concepts

- **Client-side hashing** — the original document is never uploaded; only its 64-character SHA-256 fingerprint reaches the server.
- **Dual-chain anchoring** — Polygon for cost and finality (~$0.002/tx), Bitcoin via OpenTimestamps for long-term gravitas.
- **Open-source verifier** — [stamp-verify](https://github.com/stamp-verify/stamp-verify) is a public MIT-licensed CLI and GUI that any third party can use to re-verify a certificate without contacting bastamp.com.
- **Bulk stamping** — up to 100 files in a single batch; one on-chain transaction, N independent certificates.
- **23 locales** — full UI and PDF certificate translations including Italian, German, French, Spanish, Arabic, Chinese, Japanese, Korean, Hebrew, Russian, and more.

## Primary pages

- [Landing / product overview](https://bastamp.com/) — what the product does, dual-chain architecture, pricing, legal framing.
- [Pricing](https://bastamp.com/#pricing) — credit packs starting at $2.99/stamp, no subscription. Enterprise tier available.
- [Legal basis](https://bastamp.com/#legal) — table of 30+ jurisdictions with specific statute references.
- [FAQ](https://bastamp.com/#faq) — court admissibility, chain of custody, expert reports, comparison with notarial timestamps.
- [Public verification](https://bastamp.com/verify) — paste a hash or upload a file to independently verify any stamp.

## Target audience

Legal professionals (lawyers, notaries, compliance officers), enterprises needing evidence of document integrity for contracts, NDAs, board minutes, intellectual property disclosures, M&A data rooms, and regulatory submissions.

## Smart contract (Polygon)

- Address: `0x50ddee9a1afbe1a14f1cf01b379535f897b3ca3d`
- Verified source: https://polygonscan.com/address/0x50ddee9a1afbe1a14f1cf01b379535f897b3ca3d#code

## Contact

- Operator: Aletheia Tech Ltd, London, UK
- General inquiries: contact@bastamp.com
- Source of the open-source verifier: https://github.com/stamp-verify/stamp-verify