挖矿：headerHash如何计算

kingccc · September 16, 2019, 7:14am

矿池给矿工下发任务有个headerHash，不知道如何计算

quake · September 17, 2019, 8:02am

你说的是 pow_hash 吧？
pow_hash 是通过 Block header 上的 calc_pow_hash 这个方法计算出来的：

nervosnetwork/ckb/blob/bcca3552fd20b1d6088a46b6b6cb558cdb844e80/miner/src/miner.rs#L76


    }
}


// remove `allow` tag when https://github.com/crossbeam-rs/crossbeam/issues/404 is solved
#[allow(clippy::zero_ptr, clippy::drop_copy)]
pub fn run(&mut self) {
    loop {
        select! {
            recv(self.work_rx) -> msg => match msg {
                Ok(work) => {
                    let pow_hash= work.block.header().calc_pow_hash();
                    let target = difficulty_to_target(&work.block.header().raw().difficulty().unpack());
                    self.works.insert(pow_hash.clone(), work);
                    self.notify_workers(WorkerMessage::NewWork{pow_hash, target});
                },
                _ => {
                    error!("work_rx closed");
                    break;
                },
            },
            recv(self.nonce_rx) -> msg => match msg {

这个方法实现就是把 header 序列化后的 bytes 做一次 blake2b：

github.com

nervosnetwork/ckb/blob/81af818d07fed12b4208008abe6907bfa59ecf9e/util/types/src/extension/calc_hash.rs#L20


// Please call the methods which specify the hash content.
pub(crate) trait CalcHash {
    fn calc_hash(&self) -> packed::Byte32;
}


impl<'r, R> CalcHash for R
where
    R: Reader<'r>,
{
    fn calc_hash(&self) -> packed::Byte32 {
        blake2b_256(self.as_slice()).pack()
    }
}


/*
 * Calculate special hash for packed bytes wrappers.
 */


macro_rules! impl_calc_special_hash_for_entity {
    ($entity:ident, $func_name:ident) => {
        impl packed::$entity {

因为序列化的方案最近才最终确定，这部分的相关文档正在陆续补上。

kingccc · September 17, 2019, 8:42am

矿池下发任务给矿工有个参数header_hash, 这个是序列号之后调用blake2b算法得到一个32字节的hash, 如何进行序列化，
例如：调用get_block_template获取挖矿任务有以下字段需要序列号：

“version”: “0”,
“difficulty”: “0x35a9ae20a27f”,
“parent_hash”: “0x42ec33072ad79065ccf587fa24e2825e93f8688a27862c0bf029b2dac9491956”,
“timestamp”: “1568087566567”,
“number”: “33849”,
“epoch”: “22”,
“dao”: “0x01000000000000000af1677430652600768065bdfc3b440000ff61346d330100”,

序列化操作是否如下？下面哪些字段长度是固定？如果是固定的固定的长度是多少，是否需要补0
version: 占一个字节？, 序列后16进制表示为：0x00
difficulty: 序列后16进制表示为：0x35a9ae20a27f
parent_hash: 序列后16进制表示为：0x42ec33072ad79065ccf587fa24e2825e93f8688a27862c0bf029b2dac9491956
timestamp: 序列后16进制表示为：0x01 6d 19 4d 68 e7
number：序列后16进制表示为：0x84 39
epoch: 序列后16进制表示为：0x16
dao: 序列后16进制表示为：0x01000000000000000af1677430652600768065bdfc3b440000ff61346d330100

序列化的结果：把上面所有的字段依次保存到uint8_t buf[] 中
调用blake2b算法生成header_hash:
而blake2b算法有几个可以设置的参数：personal, salt, key，这几个需要设置多少，或者默认值0就行？
是否可以这样调用：key="", keylen=0
int blake2b( void *out, size_t outlen, const void *in, size_t inlen, const void *key, size_t keylen );

watson · September 17, 2019, 9:58am

github.com

nervosnetwork/ckb-sdk-java/blob/develop/core/src/main/java/org/nervos/ckb/utils/Serializer.java

package org.nervos.ckb.utils;

import static org.nervos.ckb.methods.type.cell.CellDep.CODE;

import java.util.ArrayList;
import java.util.List;
import org.nervos.ckb.methods.type.OutPoint;
import org.nervos.ckb.methods.type.Script;
import org.nervos.ckb.methods.type.cell.CellDep;
import org.nervos.ckb.methods.type.cell.CellInput;
import org.nervos.ckb.methods.type.cell.CellOutput;
import org.nervos.ckb.methods.type.transaction.Transaction;
import org.nervos.ckb.type.dynamic.Bytes;
import org.nervos.ckb.type.dynamic.Dynamic;
import org.nervos.ckb.type.dynamic.Table;
import org.nervos.ckb.type.fixed.*;

/** Copyright © 2019 Nervos Foundation. All rights reserved. */
public class Serializer {

This file has been truncated. show original

这里是 Java SDK 实现 Transaction 结构序列化的代码，希望可以供你参考

kingccc · September 18, 2019, 9:28am

“version”: “0”,
“difficulty”: “0x35a9ae20a27f”,
“parent_hash”: “0x42ec33072ad79065ccf587fa24e2825e93f8688a27862c0bf029b2dac9491956”,
“timestamp”: “1568087566567”,
“number”: “33849”,
“epoch”: “22”,
“dao”: “0x01000000000000000af1677430652600768065bdfc3b440000ff61346d330100”,

上面是get_block_template获取的一部分字段数据，用于计算head_hash，上面的数据序列化之后，我得到：0x0000000035a9ae20a27f42ec33072ad79065ccf587fa24e2825e93f8688a27862c0bf029b2dac94919560000016d194d7aad0000000000008439000000000000001601000000000000000af1677430652600768065bdfc3b440000ff61346d330100, 不知道是否正确？

watson · September 19, 2019, 1:10am

由于 SDK 中目前只对 Transaction 和 Script 结构进行了序列化操作，Header 暂时没有处理（考虑到 SDK 一侧暂时不需要对 Header 进行序列化），不过你可以将通过 SDK 提供的模板得到序列化结果与 CKB 链上做交叉验证，如果 CKB 能反序列化成功，或者其他方式验证通过，那就说明序列化结果是对的。

kingccc · September 19, 2019, 1:50am

get_block_template 获取任务如下，使用C语言，如何计算head_hash？

{
“jsonrpc”: “2.0”,
“result”: {
“bytes_limit”: “1024”,
“cellbase”: {
“cycles”: null,
“data”: {
“cell_deps”: [],
“header_deps”: [],
“inputs”: [{
“previous_output”: {
“index”: “4294967295”,
“tx_hash”: “0x0000000000000000000000000000000000000000000000000000000000000000”
},
“since”: “33849”
}],
“outputs”: [{
“capacity”: “86517358461”,
“lock”: {
“args”: [“0xddc1ddf9c135061b7635ca51e735fc2b03cee339”],
“code_hash”: “0x1892ea40d82b53c678ff88312450bbb17e164d7a3e0a90941aa58839f56f8df2”,
“hash_type”: “type”
},
“type”: null
}],
“outputs_data”: [“0x”],
“version”: “0”,
“witnesses”: [{
“data”: [“0x54811ce986d5c3e57eaafab22cdd080e32209e39590e204a99b32935f835a13c01”, “0xc61a169ab30e7de7ceff6c3a75733d99fe742a8c”]
}]
},
“hash”: “0xaa7f936c172f5fe7e2ae30c726ba44d8ac0a22dd77f43a2a1b3534648f0c17b6”
},
“current_time”: “1568087571117”,
“cycles_limit”: “51673900000”,
“dao”: “0x01000000000000000af1677430652600768065bdfc3b440000ff61346d330100”,
“difficulty”: “0x35a9ae20a27f”,
“epoch”: “22”,
“number”: “33849”,
“parent_hash”: “0x42ec33072ad79065ccf587fa24e2825e93f8688a27862c0bf029b2dac9491956”,
“proposals”: [],
“transactions”: [],
“uncles”: [],
“uncles_count_limit”: “2”,
“version”: “0”,
“work_id”: “0”
},
“id”: 2
}

watson · September 19, 2019, 2:12am

header_hash = blake2b(serialize(header))

你需要先对 header 结构体本身做序列化，然后对序列化的结果进行 blake2b 计算。可以参考 SDK 中 transaction_hash 的计算过程。

github.com

nervosnetwork/ckb-sdk-java/blob/develop/core/src/main/java/org/nervos/ckb/methods/type/transaction/Transaction.java#L80-L84


public String computeHash() {
  Blake2b blake2b = new Blake2b();
  blake2b.update(Encoder.encode(Serializer.serializeTransaction(this)));
  return blake2b.doFinalString();
}

kingccc · September 19, 2019, 2:46am

get_block_template 没有header结构体

kingccc · September 19, 2019, 2:49am

header对应get_block_template的哪些字段，字段长度多少

watson · September 19, 2019, 5:34am

get_block_template 是 CKB 内部的接口，而非 RPC，可能得需要看 CKB 源码，或者请 @quake 帮忙解答一下

fire5678 · September 23, 2019, 2:43pm

同问，我们也是卡在 header_hash不知道如何从get block template信息中得到
blake2b调用已经搞定

doitian · November 16, 2019, 9:46pm

https://gist.github.com/moofone/67f2b2fc2dcf0c5596d0f55d8ee7d950 这个有个案例，希望有所帮助