<p>The block output you're seeing from bfgminer ("0000000256d14795...") is the wrong thing to be hashing; it looks like it isn't swabbing the fields when it logs.  The first four bytes of a block are a little endian format version number, and I do not think block format version 33554432 will be released for some time.</p>

<p>Compare the example given on bitcoin.it (<a href="https://en.bitcoin.it/wiki/Block_hashing_algorithm" rel="nofollow">https://en.bitcoin.it/wiki/Block_hashing_algorithm</a>): the initial bytes are "01000000" (format version 1 as a little-endian uint32_t).</p>

CC BY-SA 3.0
2013-05-30T08:55:42.250Z
Thanks. Just for the record, the version field, prevhash, time, and difficulty fields require swabbing. The merkle root doesn't appear to need swabbing, and my error above is failing to hash the coinbase before calculating the root.
zeta
CC BY-SA 3.0
2013-05-29T11:55:04.183Z
2013-05-29T11:55:04.183Z
Andrea Shepard
<p>I need some help trying to verify that my implementation is correct or not. I'm trying to make a Stratum mining client. </p>

<p>All byte orders are as is directly received from the server, without endian swapping</p>

<p>Here's the data: </p>

<pre><code>{"result": [[["mining.notify", "108fa002000000001"], ["mining.set_difficulty", "108fa002000000002"]], "108fa00200000000", 4], "id": 1, "error": null}
{"params": ["1369818357 489", "56d14795eadabe52464b0c6410f8c1f70c0af2c5444379160000002400000000", "01000000010000000000000000000000000000000000000000000000000000000000000000ffffffff51039aa3030d00456c69676975730051a5c4f5fabe6d6d28db22e01b9dceb2e0dc8d7cc01bfc4dcdbce7f7a49c57020c827389efdcea970200000000000000002f7373302f00", "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", ["d8481cf9050990f425c82fd0f4b0d1dcd3166435cd56eb8f00c76244704812d8", "815bb21cfd4bf9d26b8b85937390bfb6c39f84a81f8580ba0028c935543cfeec", "1450b5fe41462f25ca2b8f1f8df1fc08732532ec5b72039f5ad1ad1bd0a3546c", "af94c2da313d385e2c0c8812c70f8e86809e90f95e79f25e6cdf6c98eac1232a", "53276d253bee618e675e32b0367e3a786e717bc7e766b165caa8d5de84ef1bf8", "b0e99cef9b6a55684b8a399a54842a5123163c2fe324a9c563f4d5314ff50684", "1b559b9b59306deb2d23716fecd213852efe519cbf297c9b10178be71c1013e9"], "00000002", "1a016164", "51a5c4f5", false], "id": null, "method": "mining.notify"}
{"params": ["redacted", "1369818357 489", "12000000", "51a5c4f5", "41f20233"], "id": 2, "method": "mining.submit"}
</code></pre>

<p>I've obtained this from running bfgminer and dumped the share logs and tcpdumped the connection to the pool. </p>

<p>bfgminer has logged the block header as (with padding):</p>

<pre><code>0000000256d14795eadabe52464b0c6410f8c1f70c0af2c5444379160000002400000000751b1aba
ddefb3e3e74c3ac8bbe49787a5ae21703b873e0958a9441a0871d2dc51a5c4f51a01616441f20233
00000080000000000000000000000000000000000000000000000000000000000000000000000000
0000000080020000
</code></pre>

<p>Hashing the data as it appears in the usual fashion, ie., sha256(sha256(data)), doesn't yield the hash that it says it obtained, which is <code>d8b5ed97e69707dc17cae1c23e672818a18b75fd362bb698fad4433b00000000</code>.</p>

<p>I thought I could calculate the merkle root by the usual fashion, with the nonces obtained from the above subscription and the submission message:</p>

<pre><code>&gt;&gt;&gt; coinbase = coinbase1 + extranonce1 + extranonce2 + coinbase2
&gt;&gt;&gt; coinbase_bin = binascii.unhexlify(coinbase)
&gt;&gt;&gt; root = coinbase_bin
&gt;&gt;&gt; for h in merkle_branch:
...   root = hashlib.sha256(hashlib.sha256(root + binascii.unhexlify(h)).digest()).digest()
&gt;&gt;&gt; binascii.hexlify(root)
'eed07afc76bc7b15dc5871581a2460c7473ed68573082a0e5864140db0d11803'
</code></pre>

<p>which is wrong too.</p>

<p>Can someone tell me what's going on here? What do I need to swap and what do I need to keep as-is? Or can someone give me a subscription message, a work notification, and a submission message, and show me how to perform all the validation steps?</p>

<hash><stratum>
Sample worked Stratum example
zeta
# Sample worked Stratum example

(Asked by: username_0 on 2013-05-29)

I need some help trying to verify that my implementation is correct or not. I'm trying to make a Stratum mining client.

All byte orders are as is directly received from the server, without endian swapping

Here's the data:

```
{"result": [[["mining.notify", "108fa002000000001"], ["mining.set_difficulty", "108fa002000000002"]], "108fa00200000000", 4], "id": 1, "error": null}
{"params": ["1369818357 489", "56d14795eadabe52464b0c6410f8c1f70c0af2c5444379160000002400000000", "01000000010000000000000000000000000000000000000000000000000000000000000000ffffffff51039aa3030d00456c69676975730051a5c4f5fabe6d6d28db22e01b9dceb2e0dc8d7cc01bfc4dcdbce7f7a49c57020c827389efdcea970200000000000000002f7373302f00", "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", ["d8481cf9050990f425c82fd0f4b0d1dcd3166435cd56eb8f00c76244704812d8", "815bb21cfd4bf9d26b8b85937390bfb6c39f84a81f8580ba0028c935543cfeec", "1450b5fe41462f25ca2b8f1f8df1fc08732532ec5b72039f5ad1ad1bd0a3546c", "af94c2da313d385e2c0c8812c70f8e86809e90f95e79f25e6cdf6c98eac1232a", "53276d253bee618e675e32b0367e3a786e717bc7e766b165caa8d5de84ef1bf8", "b0e99cef9b6a55684b8a399a54842a5123163c2fe324a9c563f4d5314ff50684", "1b559b9b59306deb2d23716fecd213852efe519cbf297c9b10178be71c1013e9"], "00000002", "1a016164", "51a5c4f5", false], "id": null, "method": "mining.notify"}
{"params": ["redacted", "1369818357 489", "12000000", "51a5c4f5", "41f20233"], "id": 2, "method": "mining.submit"}

```

I've obtained this from running bfgminer and dumped the share logs and tcpdumped the connection to the pool.

bfgminer has logged the block header as (with padding):

```
0000000256d14795eadabe52464b0c6410f8c1f70c0af2c5444379160000002400000000751b1aba
ddefb3e3e74c3ac8bbe49787a5ae21703b873e0958a9441a0871d2dc51a5c4f51a01616441f20233
00000080000000000000000000000000000000000000000000000000000000000000000000000000
0000000080020000

```

Hashing the data as it appears in the usual fashion, ie., sha256(sha256(data)), doesn't yield the hash that it says it obtained, which is `d8b5ed97e69707dc17cae1c23e672818a18b75fd362bb698fad4433b00000000`.

I thought I could calculate the merkle root by the usual fashion, with the nonces obtained from the above subscription and the submission message:

```
>>> coinbase = coinbase1 + extranonce1 + extranonce2 + coinbase2
>>> coinbase_bin = binascii.unhexlify(coinbase)
>>> root = coinbase_bin
>>> for h in merkle_branch:
...   root = hashlib.sha256(hashlib.sha256(root + binascii.unhexlify(h)).digest()).digest()
>>> binascii.hexlify(root)
'eed07afc76bc7b15dc5871581a2460c7473ed68573082a0e5864140db0d11803'

```

which is wrong too.

Can someone tell me what's going on here? What do I need to swap and what do I need to keep as-is? Or can someone give me a subscription message, a work notification, and a submission message, and show me how to perform all the validation steps?

**Tags:** hash, stratum


---

## 1 answers

### Answer by username_1 on 2013-05-29. Score: 1 | Accepted answer

The block output you're seeing from bfgminer ("0000000256d14795...") is the wrong thing to be hashing; it looks like it isn't swabbing the fields when it logs. The first four bytes of a block are a little endian format version number, and I do not think block format version 33554432 will be released for some time.

Compare the example given on bitcoin.it (<https://en.bitcoin.it/wiki/Block_hashing_algorithm>): the initial bytes are "01000000" (format version 1 as a little-endian uint32\_t).

> **Comments:**
> **username_0**: Thanks. Just for the record, the version field, prevhash, time, and difficulty fields require swabbing. The merkle root doesn't appear to need swabbing, and my error above is failing to hash the coinbase before calculating the root.  

---

