From Lightning Network documentation:

Used in several of the BOLT documents to denote the genesis hash of a target blockchain. This allows nodes to create and reference channels on several blockchains. Nodes are to ignore any messages that reference a chain_hash that are unknown to them. Unlike bitcoin-cli, the hash is not reversed but is used directly.

For the main chain Bitcoin blockchain, the chain_hash value MUST be (encoded in hex): 6fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d6190000000000.

However this wiki entry about Bitcoin's genesis block has

GetHash() = 0x000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f

Indeed, inputting the latter value into blockchain.info yields Block 0, while the former value cannot be found on blockchain.info.

Why does the value 6fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d6190000000000 appear in Lightning Network as "Bitcoin's genesis hash"?

2 Answers 2


They're exactly the same number; one is written in little endian notation and the other is big endian. Notice that the bytes (two-hex-digit pairs) are exactly reversed from one to the other.

Block explorers like blockchain.info usually expect big-endian for block hashes. The proof-of-work requirement means that the most significant bits have to be zero, so big endian makes it easier to see this.


It is the same hash but reversed since bitcoin transmits data using little endian format (most significant byte last)

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