Pow check of events incoming

[arkanoider]

Hi @grunch ,

mostrod now checks the POW of incoming events.
Settings file now in [mostro] section has also pow value ( 0 means no pow ).

Added also pow requested by mostro in info event.

[grunch]

I tested it with pow = 1, then I publish a new order with mostro-cli last commit and mostrod publish the order

If I try to cancel the event now I get INFO mostrod::app: Not POW verified event! and it doens't cancel, that is ok

[arkanoider]

I tested it with pow = 1, then I publish a new order with mostro-cli last commit and mostrod publish the order

If I try to cancel the event now I get INFO mostrod::app: Not POW verified event! and it doens't cancel, that is ok

I noticed this too...for example i tried with pow=10 on mostrod and pow=8 on cli and it can pass because could happen that you create an event on cli with id like:

0x001efrys....

0 - 4 bits to 0 so 4
0 - 4 bits to 0 so 4 other 0... 8 totally...
1 - in binary is 0010 so you have 10 zero leading bits and it passes...

I think that we need to think to pow as some robust one like 30 so cannot have a random lucky shot...if you put pow=1 on mostrod it's not so incredible that an event can be generated with the first digit that is zero.

This is my opinion, I can ask confirmation to @yukibtc in case or just look at the code.

[grunch]

I tested it with pow = 1, then I publish a new order with mostro-cli last commit and mostrod publish the order
If I try to cancel the event now I get INFO mostrod::app: Not POW verified event! and it doens't cancel, that is ok

I noticed this too...for example i tried with pow=10 on mostrod and pow=8 on cli and it can pass because could happen that you create an event on cli with id like:

0x001efrys....

0 - 4 bits to 0 so 4 0 - 4 bits to 0 so 4 other 0... 8 totally... 1 - in binary is 0010 so you have 10 zero leading bits and it passes...

I think that we need to think to pow as some robust one like 30 so cannot have a random lucky shot...if you put pow=1 on mostrod it's not so incredible that an event can be generated with the first digit that is zero.

This is my opinion, I can ask confirmation to @yukibtc in case or just look at the code.

I see, great job, let's merge this 👶🏽

[grunch]

🐤

[yukibtc]

I tested it with pow = 1, then I publish a new order with mostro-cli last commit and mostrod publish the order
If I try to cancel the event now I get INFO mostrod::app: Not POW verified event! and it doens't cancel, that is ok

I noticed this too...for example i tried with pow=10 on mostrod and pow=8 on cli and it can pass because could happen that you create an event on cli with id like:

0x001efrys....

0 - 4 bits to 0 so 4 0 - 4 bits to 0 so 4 other 0... 8 totally... 1 - in binary is 0010 so you have 10 zero leading bits and it passes...

I think that we need to think to pow as some robust one like 30 so cannot have a random lucky shot...if you put pow=1 on mostrod it's not so incredible that an event can be generated with the first digit that is zero.

This is my opinion, I can ask confirmation to @yukibtc in case or just look at the code.

Correct. A POW of 24-32 could be good.

---

Exists an option in the Client to set a min POW. Could be more efficient to use that instead of Event::check_pow, so the event will be almost immediately discarded instead of being fully parsed, verified and so on. The SDK execute these steps when receive a new relay message:

• Parse raw relay message
• Check message/event limits
• Partially parse event (only ID and pubkey)
• Check blacklist (in-memory)
• Check POW <-- HERE
• Parse missing event fields and compose full event
• Check if it's expired
• Check if it's valid
• Check if exists in db or if was already seen
• Send notification to channels

You can set POW in Client with:

let client = Client::default();
client.update_min_pow_difficulty(28);

// OR

let opts = Options::default().min_pow(28);
let client = Client::with_opts(signer, opts);

Will be logged an error message when receive an event with low difficulty.