-
Notifications
You must be signed in to change notification settings - Fork 565
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Thanks-to: Cameri and scsibug for the initial idea of using the id for PoW Thanks-to: David A. Harding for the difficulty commitment idea Signed-off-by: William Casarin <[email protected]>
- Loading branch information
Showing
2 changed files
with
94 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,93 @@ | ||
NIP-13 | ||
====== | ||
|
||
Proof of Work | ||
------------- | ||
|
||
`draft` `optional` `author:jb55` `author:cameri` | ||
|
||
This NIP defines a way to generate and interpret Proof of Work for nostr notes. Proof of Work (PoW) is a way to add a proof of computational work to a note. This is a bearer proof which all relays and clients can universally validate with a small amount of code. This proof can be used as a means of spam deterrence. | ||
|
||
`difficulty` is defined to be the number of leading zero bits in the `NIP-01` id. For example, an id of `000000000e9d97a1ab09fc381030b346cdd7a142ad57e6df0b46dc9bef6c7e2d` has a difficulty of `36` with `36` leading 0 bits. | ||
|
||
Mining | ||
------ | ||
|
||
To generate PoW for a `NIP-01` note, a `nonce` tag is used: | ||
|
||
```json | ||
{"content": "It's just me mining my own business", "tags": [["nonce", "1", "20"]]} | ||
``` | ||
|
||
When mining, the second entry to the nonce tag is updated, and then the id is recalculated (see [NIP-01](./01.md)). If the id has the desired number of leading zero bits, the note has been mined. It is recommended to update the `created_at` as well during this process. | ||
|
||
The third entry to the nonce tag `SHOULD` contain the target difficulty. This allows clients to protect against situations where bulk spammers targeting a lower difficulty get lucky and match a higher difficulty. For example, if you require 40 bits to reply to your thread and see a committed target of 30, you can safely reject it even if the note has 40 bits difficulty. Without a committed target difficulty you could not reject it. Committing to a target difficulty is something all honest miners should be ok with, and clients `MAY` reject a note matching a target difficulty if it is missing a difficulty commitment. | ||
|
||
Example mined note | ||
------------------ | ||
|
||
```json | ||
{ | ||
"id": "000006d8c378af1779d2feebc7603a125d99eca0ccf1085959b307f64e5dd358", | ||
"pubkey": "a48380f4cfcc1ad5378294fcac36439770f9c878dd880ffa94bb74ea54a6f243", | ||
"created_at": 1651794653, | ||
"kind": 1, | ||
"tags": [ | ||
[ | ||
"nonce", | ||
"776797", | ||
"20" | ||
] | ||
], | ||
"content": "It's just me mining my own business", | ||
"sig": "284622fc0a3f4f1303455d5175f7ba962a3300d136085b9566801bc2e0699de0c7e31e44c81fb40ad9049173742e904713c3594a1da0fc5d2382a25c11aba977" | ||
} | ||
``` | ||
|
||
Validating | ||
---------- | ||
|
||
Here is some reference C code for calculating the difficulty (aka number of leading zero bits) in a nostr note id: | ||
|
||
```c | ||
int zero_bits(unsigned char b) | ||
{ | ||
int n = 0; | ||
|
||
if (b == 0) | ||
return 8; | ||
|
||
while (b >>= 1) | ||
n++; | ||
|
||
return 7-n; | ||
} | ||
|
||
/* find the number of leading zero bits in a hash */ | ||
int count_leading_zero_bits(unsigned char *hash) | ||
{ | ||
int bits, total, i; | ||
for (i = 0, total = 0; i < 32; i++) { | ||
bits = zero_bits(hash[i]); | ||
total += bits; | ||
if (bits != 8) | ||
break; | ||
} | ||
return total; | ||
} | ||
``` | ||
Querying relays for PoW notes | ||
----------------------------- | ||
Since relays allow searching on prefixes, you can use this as a way to filter notes of a certain difficulty: | ||
``` | ||
$ echo '["REQ", "subid", {"ids": ["000000000"]}]' | websocat wss://some-relay.com | jq -c '.[2]' | ||
{"id":"000000000121637feeb68a06c8fa7abd25774bdedfa9b6ef648386fb3b70c387", ...} | ||
``` | ||
Delegated Proof of Work | ||
----------------------- | ||
Since the `NIP-01` note id does not commit to any signature, PoW can be outsourced to PoW providers, perhaps for a fee. This provides a way for clients to get their messages out to PoW restricted relays without having to do any work themselves, which is useful for energy constrained devices like on mobile |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters