So.
I've said I would have added PayPal USD (PYUSD) token support for purchasing applications on the Ur uncensorable Life and DogeOS user repository and application store in the context of the "seamless transactions, infinite possibilities hackaton."
Still Google RPC supports only Ethereum mainnet and Holesky, and doing stuff on there is stupidly expensive, so if I simply deployed an Ethereum Ur instance still probably nobody would ever use it to like buy $1 applications, which actually it seems to be the biggest revenue pool for those, and only if you sell millions.
So more or less an Ethereum Ur would be a fun trick but it would be completely unusable in practice.
Now I can still add support for PYUSD on Gnosis, still I wouldn't be using the Google RPC at all.
Also probably PayPal wouldn't like much a project which roughly exposes its token's customers to a stable-coin baked network from a competitor.
Not that I care much frankly, as what the Ur is supposed to do is to make people able to buy uncensorable applications whichever way, so I will probably do it just the same.
Anyway, I was wondering if for the hackaton the right compromise might actually be to set up a one-way cross-chain bridge with a permissionless router, which actually on Gnosis wouldn't be one-way as there is the official centralized one available I could use to move the money back.
So I've never written a bridge nor I've ever read the code for one, still from what I've come to understand none of the existing works with a permissionless router, or at least they all depend on usually a single actor keeping a server up.
Since it's happening nowadays that I'm writing a lot of stuff which is making lots of centralized services virtually useless without getting a dime nor any kind of recognizement from this activity, I've thought "why not doing the same also for network bridges? in the end its not like anybody will ever thank, provide for or support me whatever I can do, so why not proving once again humanity the best thing it could happen to earth is for it to disappear?".
Premise I have not thought in the slightest about the caveats of the following scheme, that I keep forgetting how a 4-way handshake works and that I have a terrible headache right now, I was imagining something like the following.
If anybody sees any conceptual or practical issue with it, if you tell me I could probably think you're not like unworthy of the oxygen you're breathing.
Feel free to replace XDAI with the symbol for the
centralized bridged version of PYUSD.
Balance:
user A:
+10 PYUSD
+10 XDAI
user B:
+10 PYUSD
0 GPYUSD
0 XDAI
vault E:
0 PYUSD
vault G:
0 XDAI
0 GPYUSD
- User A deposits 10 XDAI on Gnosis vault and 10 PYUSD on Ethereum vault.
Transaction E1:
user A => vault E
-10PYUSD +10 PYUSD
Transaction G1:
user A => vault G
-10 XDAI +10 XDAI
+10 GPYUSD
Balance:
user A:
0 PYUSD
0 XDAI
user B:
+10 PYUSD
0 GPYUSD
0 XDAI
vault E:
+10 PYUSD
vault G:
+10 XDAI
+10 GPYUSD
- User B requests to bridge 10 PYUSD to Ethereum vault from user A with timeout
tand locks user A funds on Gnosis vault by presenting the signature of the request.
Transaction E2:
user B => vault E
-10 PYUSD (A, t) +10 PYUSD
Transaction G2:
user B => vault G
sig(E2)
Balance:
user A:
0 PYUSD
0 XDAI
user B:
0 PYUSD
0 GPYUSD
0 XDAI
vault E:
+20 PYUSD
vault G:
+10 XDAI
+10 GPYUSD
- User A presents valid signature to Gnosis vault of user B request to bridge 10 PYUSD on Ethereum vault, so user B is allowed to receive 8 GPYUSD from Gnosis vault before timeout is reached.
Transaction G3:
user A => vault G
sig(E2)
- User B sends request to receive 8 GPYUSD from Gnosis vault and user A receives 1 XDAI.
Transaction G4:
user B => vault G
+8 GPYUSD -8 GPYUSD
vault G => user A
-1 XDAI +1 XDAI
Balance:
user A:
0 PYUSD
+1 XDAI
user B:
0 PYUSD
+8 GPYUSD
0 XDAI
vault E:
+20 PYUSD
vault G:
+9 XDAI
+2 GPYUSD
- Before timeout
tis reached user A presents valid signature to Ethereum vault of user B receiving the 8 GPYUSD so he is allowed to take user B 10 PYUSD and his own PYUSD.
Transaction E3:
user A => vault E
sig(G4)
vault E => user A
-20 PYUSD +20PYUSD
Balance:
user A:
+20 PYUSD
+1 XDAI
user B:
0 PYUSD
+8 GPYUSD
0 XDAI
vault E:
0 PYUSD
vault G:
+9 XDAI
+1 GPYUSD
- At a later time user B or somebody else returns the GPYUSD to the vault G and redeems the XDAI.
Transaction G5:
user B => vault G
-8 GPYUSD +8 GPYUSD
vault G => user B
-7 XDAI +7 XDAI
vault G => null address
-7 GPYUSD => +7 GPYUSD
Balance:
user A:
+20 PYUSD
+1 XDAI
user B:
0 PYUSD
0 GPYUSD
+7 XDAI
vault E:
0 PYUSD
vault G:
+2 XDAI
+1 GPYUSD
- The bridge author takes some money to further think about some other way to make the world a better place.
Transaction G6:
bridge author => vault G
dinner
vault G => bridge author
-1 XDAI +1 XDAI
vault G => null address
-1 GPYUSD => +1 GPYUSD
Balance:
bridge author:
+1 XDAI
vault E:
0 PYUSD
vault G:
+1 XDAI
+1 GPYUSD
- User A can be anybody, so user B and user A can be the same person.
- The bridge retains a share of the funds.
- In case user A and user B are the same person and the Ethereum transactions are never actually transmitted to the network, the GPYUSD token retains its value.
- In case user A and bridge author are the same person, the bridge share must be large enough to cover the expenses for network fees on Ethereum and Gnosis network.
- Why I've never heard about cross-chain clocks?
I've linked this document to the Stack Exchange question I've asked while writing it.
The question has been deleted on the ground 'the link could disappear', so I'm uploading a version of this document to the EVMFS so the censors on there won't complain.
The content in this page, as the rest of this repository is released under the terms of the GNU Affero General Public License version 3.
If you're wondering why I do release prose with a code license, the answer may be I am a computer.