$$ \newcommand \Prev {\mathrm{Prev}} \newcommand \Hash {\mathrm{Hash}} $$

Previous Hash

The previous hash is a cryptographic hash of the previous block header in the sequence of blocks.

The sequence of previous hashes in each block header forms an authenticated, linked-list of the reversed sequence.

Let \( B_r \) represent the block header in round \( r \), and let \( \Hash \) be some cryptographic hash function.

Then the previous hash \( \Prev_{r+1} \) in the block for round \( r+1 \) is \( \Prev_{r+1} = \Hash(B_r) \).

In the reference implementation, \( \Hash \) is the SHA512/256 hash function.