[p4bl0]

Indeed, GNU Taler doesn't use a blockchain, as a blockchain cannot actually implement digital cash. In a blockchain, transactions are necessarily centralized — on a distributed ledger maintained using a peer-to-peer protocol, but the transactions themselves are still account-based —, so they are effectively equivalent to wire transfers, i.e., just accounting entries: they cannot take place between two offline parties like you can do with actual cash. Also, blockchain-based digital "money" (quotes because there is no such thing, "cryptocurrencies" are purely speculative securities and that's it) need to be at the same time the currency, the long-term storage, and the transaction system.

On the contrary, GNU Taler is only a transaction system as you said, and uses advanced cryptography (double blind signatures) and infrastructure that allow it to be bearer-based, i.e., actually decentralized transactions between two offline parties can take place. Taler can actually do digital cash, with buyers privacy, and auditability and taxability of sellers.

[jgilias]

I’m confused. Why do they say in their FAQ that peer-to-peer payments only appear as such, and actually need to go through a payment provider?

https://taler.net/en/faq.html

[t_mann]

My understanding is that a Taler is a "use-once" note - you create it from a payment provider balance, then you can transfer it to someone else, but then that person then has to redeem the coupon, they can't transfer it again (at least not using the cryptographically secure protocol - they could give someone else the private key, but clearly that wouldn't be safe). So transactions in Taler look something like this: 1 convert payment provider balance to Taler note 2 send Taler note to someone else 3 recipient converts receipt back to payment provider balance 4 create a new Taler note (go to 1). The anonymity should derive from the fact that the receipt note can't be traced back to the original spendable note, and the time delay between the creation of the spendable note and the redemption of the receipt note (so arguably the system requires some level of minimum activity to achieve a practical privacy guarantee).

So in that sense it is quite different from the account or UTXO logic that most cryptocurrencies use, where balances can be transferred between accounts indefinitely. I think it's interesting to think about what problems it solves - it semi-solves anonymity in a way that might be acceptable for lawmakers and that doesn't require a backdoor (the more typical approach for 'compliant privacy'). The question is whether that is enough utility gain for regular users to justify the overhead - it seems like a simple transaction requires quite a lot of steps, key management is a non-trivial burden (for users who might not even be used to password managers eg),...

[pyrale]

> actually decentralized transactions between two offline parties can take place.

The schema they use to explain the system's mechanisms clearly shows an exchange that needs to be audited:

> Payments are made after exchanging existing money into electronic money with the help of an Exchange service, that is, a payment service provider for Taler.

That is, the transaction can be offline, but it eventually needs to pass through a central point to be effective.

[littlestymaar]

> In a blockchain, transactions are necessarily centralized — on a distributed ledger

This.