Merge pull request #473 from arkin0x/patch-1

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@ -10,13 +10,15 @@ This NIP defines a way to generate and interpret Proof of Work for nostr notes.
`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. `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.
`002f...` is `0000 0000 0010 1111...` in binary, which has 10 leading zeroes. Do not forget to count leading zeroes for hex digits <= `7`.
Mining Mining
------ ------
To generate PoW for a `NIP-01` note, a `nonce` tag is used: To generate PoW for a `NIP-01` note, a `nonce` tag is used:
```json ```json
{"content": "It's just me mining my own business", "tags": [["nonce", "1", "20"]]} {"content": "It's just me mining my own business", "tags": [["nonce", "1", "21"]]}
``` ```
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. 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.
@ -36,7 +38,7 @@ Example mined note
[ [
"nonce", "nonce",
"776797", "776797",
"20" "21"
] ]
], ],
"content": "It's just me mining my own business", "content": "It's just me mining my own business",
@ -47,33 +49,61 @@ Example mined note
Validating Validating
---------- ----------
Here is some reference C code for calculating the difficulty (aka number of leading zero bits) in a nostr note id: Here is some reference C code for calculating the difficulty (aka number of leading zero bits) in a nostr event id:
```c ```c
int zero_bits(unsigned char b) #include <stdio.h>
{ #include <stdlib.h>
int n = 0; #include <string.h>
if (b == 0) int countLeadingZeroes(const char *hex) {
return 8; int count = 0;
while (b >>= 1) for (int i = 0; i < strlen(hex); i++) {
n++; int nibble = (int)strtol((char[]){hex[i], '\0'}, NULL, 16);
if (nibble == 0) {
count += 4;
} else {
count += __builtin_clz(nibble) - 28;
break;
}
}
return 7-n; return count;
} }
/* find the number of leading zero bits in a hash */ int main(int argc, char *argv[]) {
int count_leading_zero_bits(unsigned char *hash) if (argc != 2) {
{ fprintf(stderr, "Usage: %s <hex_string>\n", argv[0]);
int bits, total, i; return 1;
for (i = 0, total = 0; i < 32; i++) { }
bits = zero_bits(hash[i]);
total += bits; const char *hex_string = argv[1];
if (bits != 8) int result = countLeadingZeroes(hex_string);
break; printf("Leading zeroes in hex string %s: %d\n", hex_string, result);
}
return total; return 0;
}
```
Here is some JavaScript code for doing the same thing:
```javascript
// hex should be a hexadecimal string (with no 0x prefix)
function countLeadingZeroes(hex) {
let count = 0;
for (let i = 0; i < hex.length; i++) {
const nibble = parseInt(hex[i], 16);
if (nibble === 0) {
count += 4;
} else {
count += Math.clz32(nibble) - 28;
break;
}
}
return count;
} }
``` ```