If I look at a block


I can see the value of the merkel root: 9fe31d0d9d06d9da341a3ee757c57bb29af522796d5d9efa5efded8cda1684a4

Which is supposedly the hash of the hash of all transactions.

Is this value randomly? Could it be manipulated, through people spoofing transactions, or is it cryptographically improbable to know in advance?

I know that the block isn't cryptographically secure for the reason mentioned below, but I was wondering if the merkle tree itself was, thanks!

1 Answer 1


000000000000000004f0cc322f551e39676f781186441614da3281bbc7d373e0 is not the merkle root, it's the block hash. It seems that's what you are asking about, so I'll answer that.

It's not random, nor cryptographically secure random.

Not random: As you can see, it begins with many zeroes, which a random hash is VERY unlikely to have. The right-most bits are random for the most part, but the value as a whole is not random because of the requirement that the block hash begin with so many zeroes to be a valid block.

Not cryptographically secure: A miner could, although it would be expensive for them to do so, mine many blocks and only submit ones that end in 'FF' for example. So, miners have the option to publish or not publish any blocks they solve. As such, since miners are producing these blocks, it is not cryptographically secure random.

  • Whoops, sorry I actually did mean the merkle root but I copied the wrong thing! I've edited my answer above, thanks! @StephenM347
    – Anthony
    Apr 16, 2016 at 16:42

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