FAQ
General Questions
How does ATL differ from a Blockchain?
ATL is an append-only log with cryptographic proofs, not a full blockchain. It sacrifices decentralized consensus at the ingestion level for extreme performance (millions of TPS) and privacy, while maintaining immutability through periodic anchoring in existing blockchains like Bitcoin.
Why use TSA (RFC 3161) AND Bitcoin?
They solve different problems:
- TSA provides legally recognized proof of time from a centralized authority.
- Bitcoin provides mathematically guaranteed proof of existence from a decentralized network. Using both ensures that your proof remains valid even if a TSA service goes down or a blockchain changes.
Privacy & Security
Does the Log Operator see my private data?
Only if you explicitly choose to provide it.
By default, the ATL Protocol only requires a cryptographic hash to guarantee integrity. If you provide only the hash, the Log Operator never sees your original data.
However, some Log Operators may offer optional data custody services. In this case, you may choose to send the original data (payload) to the operator for long-term storage and easier proof generation. This is always an opt-in feature and is not required for the protocol to function.
Is ATL compliant with GDPR?
Yes. Since ATL only stores hashes in the immutable log, you can comply with the “Right to Erasure” by deleting the original data (payload) from your storage. The hash in the log remains as a mathematical constant but no longer links to any personal information.
Technical Details
Why use JCS (RFC 8785)?
Traditional JSON is not deterministic (keys can be in any order, whitespace varies). JCS ensures that the same JSON object always produces the same hash, regardless of the library or language used to generate it.
What happens if the Log Operator disappears?
Because ATL receipts are self-contained, they can be verified offline. As long as you have the receipt, the original data, and the Log Operator’s public key, you can prove your fact’s integrity forever, even without the operator’s infrastructure.
How do I know the Log Operator hasn’t deleted or changed old entries?
ATL uses Consistency Proofs (RFC 9162) to mathematically guarantee that the log is append-only. When you verify a receipt, you can request a consistency proof that demonstrates the current tree is a strict extension of the previous tree you trusted. If the operator tried to delete or modify any entry, the consistency proof would fail — proving fraud without downloading the entire log.
Combined with external anchoring (RFC 3161 timestamps, Bitcoin), this makes history rewriting detectable and provable.