<p>You’re falling afoul of <a href="https://en.wikipedia.org/wiki/Endianness" rel="nofollow noreferrer">endianness</a>. To promote equality, Satoshi sought to use Big Endian representation for hashes in Bitcoin, which have the byte order the opposite of what you are producing.</p>

CC BY-SA 4.0
2021-08-02T14:19:30.370Z
Should we little endian the output hash?
Jaisal Francis
CC BY-SA 4.0
2021-08-02T09:13:58.303Z
2021-08-02T09:13:58.303Z
Claris
<p>Hi I tried hashing a already mined block with this block header 04E0FF37f09be87b288284c8e93a04fff7b4ac9b72178c2e6b4e0a00000000000000000035788eca05bccfaede03db9cb6276e9f7c125687b9321939755f03d73f15bd25C4F2EE60CE9813175230D962 <a href="https://blockchain.info/block-height/691000" rel="nofollow noreferrer">of this block</a> and I hashed it two times but the output zero are at end of the hash. b11f24d772b9fee7132b62e0bd17fefa76d29848e6930c000000000000000000</p>
<p>How does it work</p>

<bitcoin-core><blockchain><sha256>
Already mined block hash showing zeros at the end when I hash it in online sha256 two times
Jaisal Francis
# Already mined block hash showing zeros at the end when I hash it in online sha256 two times

(Asked by: username_0 on 2021-08-02)

Hi I tried hashing a already mined block with this block header 04E0FF37f09be87b288284c8e93a04fff7b4ac9b72178c2e6b4e0a00000000000000000035788eca05bccfaede03db9cb6276e9f7c125687b9321939755f03d73f15bd25C4F2EE60CE9813175230D962 [of this block](https://blockchain.info/block-height/691000) and I hashed it two times but the output zero are at end of the hash. b11f24d772b9fee7132b62e0bd17fefa76d29848e6930c000000000000000000

How does it work

**Tags:** bitcoin-core, blockchain, sha256


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## 1 answers

### Answer by username_1 on 2021-08-02. Score: 2 | Accepted answer

You’re falling afoul of [endianness](https://en.wikipedia.org/wiki/Endianness). To promote equality, Satoshi sought to use Big Endian representation for hashes in Bitcoin, which have the byte order the opposite of what you are producing.

> **Comments:**
> **username_0**: Should we little endian the output hash?  

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