1 year ago
This is an sentiment editorial by Shinobi, a self-taught pedagogue successful the Bitcoin abstraction and tech-oriented Bitcoin podcast host.
Channel jamming is 1 of the astir threatening outstanding problems with the Lightning Network. It presents an unfastened mechanics to denial-of-service onslaught nodes connected the web to forestall them from routing, losing them wealth portion their liquidity is locked up and incapable to guardant payments that volition gain them fees. An attacker tin way a outgo done different nodes from themselves to themselves, and garbage to finalize the payment. This makes that liquidity useless for forwarding different payments until the hashed timelock declaration (HTLC) timelock expires and the outgo refunds.
Last month, Lightning developer Antoine Riard projected a ceremonial specification for a solution to this problem. In August, Riard and Gleb Naumenko published research looking astatine the wide occupation itself, arsenic good arsenic a fig of antithetic solutions that could beryllium utilized to mitigate oregon lick it. One of those projected solutions was a signifier of anonymized credentials that nodes could usage to physique a benignant of estimation scoring strategy for users routing payments done them without having to dox oregon subordinate that estimation with a static identifier that would negatively interaction peoples' privacy. This solution has present go the formal protocol proposal made by Riard past month.
Inside The Channel Jamming Mitigation Proposal
The halfway of the thought is simply a Chaumian ecash token. These are centralized tokens issued by a mint authorization successful a mode that prevents the issuance of a token from being correlated to the redemption of a token later. This is done by signing a token successful a blinded way, allowing the receiver of the token to unblind it without invalidating the signature. The issuer tin past verify it is simply a morganatic token without being capable to link that token to erstwhile it was issued.
The connection suggests utilizing these Chaumian tokens, issued by each routing node connected the network, arsenic a signifier of reputational proof. When routing a payment, a Chaumian ecash token issued by each node successful the outgo hop would beryllium wrapped up successful the bulb bundle for that node on the payment. Token units would correspond some the worth of the HTLC allowed arsenic good arsenic the refund timelock period. Before forwarding the HTLC, each node would verify that the token included successful their bulb blob is valid and has ne'er been redeemed before, lone forwarding the HTLC if some of those conditions are true.
If the HTLC settles successfully with the preimage being revealed, past each node on the outgo way signs and includes a newly-issued Chaumian token to beryllium returned backmost to the sender, on with the HTLC preimage. If the HTLC does not successfully settle, past the routing nodes "burn" the token by including it successful their spent token array and bash not contented a caller token. This forces the sender to person to get caller tokens from those nodes successful bid to way payments done them again. The full conception is that jamming attacks ever neglect to settle, truthful successful this scheme, these tokens issued by each node that you way done are burned if you execute a jamming onslaught and make the outgo of acquiring much to bash it again. Right now, jamming attacks outgo thing but time, truthful this would adhd an economical outgo to them.
So, it’s clip to sermon the elephant successful the room: however bash you bootstrap the issuance and circulation of these tokens crossed the network? Each node that you privation to way done would necessitate a token issued by them. The solution: wage for them. Another projected solution to the transmission jamming contented is up-front fees, i.e., charging a interest to adjacent effort to way a outgo careless of whether oregon not it adjacent succeeds. So, adjacent failed payments would incur a interest for the sender.
Riard’s connection is to acquisition these tokens straight from each node arsenic one-off purchases. From that constituent forward, alternatively of paying upfront fees for each payment, arsenic agelong arsenic the anterior outgo successfully settled, you would beryllium reissued "routing tokens" that would alteration your adjacent projected outgo to beryllium routed without a fee. This way, palmy payments lone wage the existent routing fee, and failed payments lone wage the up-front fee, preventing a benignant of "double fee" for palmy payments. At slightest economically, deliberation of it arsenic a benignant of middleground compromise betwixt the existent authorities of affairs where failed payments outgo thing and lone palmy payments wage a fee, and a afloat up-front interest exemplary wherever each payments wage an up-front interest and palmy ones wage a routing interest arsenic well.
Takeaways From The Proposal
Personally, I deliberation this benignant of nonstop outgo for tokens up of clip could present a ample grade of UX friction into the process of utilizing the Lightning Network. However, I deliberation determination is simply a beauteous elemental solution for that friction by tweaking the connection a bit.
Instead of having to specifically wage each node straight for Chaumian tokens up of time, the connection could beryllium hybridized much straight with the up-front interest proposal. If you person tokens for a node, past see those successful the bulb blob, if not simply wage an up-front interest straight wrong the HTLC connection and if the outgo settles successfully, you volition beryllium issued Chaumian tokens backmost successful proportionality to what your up-front interest was. This way, alternatively of having to cod tokens from galore antithetic nodes up of time, you simply get them implicit the people of making archetypal payments until you person a bully postulation from the antithetic nodes that you usage often and precise seldom person to incur the outgo of up-front fees to attain them.
Another imaginable root of friction is for node operators, and comes down to cardinal issues of Chaumian ecash itself. In bid to guarantee that a token is lone spent once, the issuer needs to support a database of each the tokens that person been spent. This grows forever, making lookups to cheque token validity much and much costly and clip consuming the bigger that database grows. Because of this, Riard proposes having these Chaumian tokens expire periodically, astatine a artifact tallness advertised successful the gossip protocol per node. This means that senders request to periodically repurchase these tokens, oregon if the implementation were to enactment it, redeem them for caller tokens signed by the caller signing cardinal aft the anterior 1 expires.
This would either spot a regular economical outgo connected the senders of payments, oregon necessitate them to periodically cheque successful to guarantee reissuance erstwhile aged tokens expire. In practice, this tin beryllium automated for radical moving their ain Lightning nodes, and for immoderate wallets built astir an Lightning work supplier (LSP) model, the LSP itself could really grip the acquisition and attraction of tokens connected behalf of its users, handling the token provisioning for its users' payments. On the fringes, however, without a afloat Lightning node oregon LSP, this could go a spot of an annoyance for airy wallet users.
I deliberation this connection could really spell a agelong mode to mitigating transmission jamming arsenic an onslaught vector, particularly if hybridized a small much tightly with the basal up-front interest scheme, and astir of the UX frictions tin beryllium handled precise easy for LSP users and radical who run their ain Lightning nodes. And adjacent if the up beforehand fees bash contiguous a precocious grade of friction, it's imaginable that simply proving power of a Bitcoin UTXO could beryllium utilized successful spot of really paying fees to get tokens.
This is simply a impermanent station by Shinobi. Opinions expressed are wholly their ain and bash not needfully bespeak those of BTC Inc oregon Bitcoin Magazine.
English (US) 