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Two Xdai -> Dai transactions not relayed

A customer brought to my attention these two transactions, only a couple of minutes apart for $100 and $650 that where successfully sent to the contract on Xdai and did not show up on Ethereum. It’s been about 5 days so I assume that moving these on will require some sort of manual intervention.

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Please read Important changes in a user interaction with the xDai bridge
from October 2nd 2020
TLDR;

A new bridge decentralization feature means withdrawals now require 2 steps. You must: 
- Initiate the bridge transaction on xDai
- Claim your Dai on Ethereum. 

Here is a quick instruction on how to claim Dai tokens on the Ethereum side:
https://www.xdaichain.com/for-users/converting-xdai-via-bridge/troubleshooting#i-used-the-xdai-bridge-ui

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Few more notes.

  • there are ~80 unclaimed transactions https://bridge-monitoring.poa.net/xdai can you estimate how many of them can be from your users?
  • there is a way of whitelisting of senders from xDai to Dai to simplify integration. In this scenario, a subsidy mode is enabled. If you would like to discuss it please DM me here or on Discord.

probably 20-40. My last commit / testing on our bridge integration was October 7th ironically. I will note that 6 days is very short for a breaking API change. Although obviously subsidizing gas prices on withdraws could not last forever.

New users may generate new keys and initiate a withdraw at any time. This would have to be more integrated with our software. Is there any documentation on the call flow to collect and submit signatures? So far everything I see is focused on the web ui?

Perhaps it would be easier to grab and operate your existing relayer code and simply pop in my own whitelist?

Correct, you can take a look either on the relayer code or get the idea how the relayer does its job from this section of the documentation.

We needed to address this quickly since we found some person who attempted to dry out the xDai bridge oracles’ balances by making dozens of withdrawals with very small value.

ouch. I did notice a withdraw minimum when I was testing on the 7th. Obviously it’s not viable as a general solution but a high enough withdraw minimum would probably allow very large transfers to be treated as ‘vip’.

Very nice this is exactly what I was looking for thank you.