I've been spending much time in the company of <insert_your_favoured_search_engine> and can only find highly theoretical, often mathematical answers to the question.
The problem I've got is I can't wrap my head around how Merkle Trees work in a practical sense.
The advertised beauty of Merkle Trees is that you can verify the integrity of a branch without the entire tree.
Ok, fine, I get it but how does that work in practice ?
Let's take the well known example of AWS Glacier. I give Amazon a calculated merkle tree root and the BLOB.
So far so good, but what I dont' get is how does that help Amazon verify the integrity of a portion ("branch" in Merkle-speak) of a file ?
I know that the tree root I calculated is the concatenation of various parts ? And given the tree is a concatenation of cryptographic hashes, you can't exactly extract the branches from the root hash ?
Does it work by virtue of brute-force (i.e. when you first send them the file, Amzazon calculates the branches at the point-of-receipt and then stores the hashes of those branches ad-infinitum ?) Or is it more clever than that ?
That's my point. I get the supposed benefits. I understand how you calculate the root. But I just can't fathom how you magically derive the branches from the root without going through the steps of calculating the branches first ?
I hope this is not the wrong place to ask this sort of question !
The problem I've got is I can't wrap my head around how Merkle Trees work in a practical sense.
The advertised beauty of Merkle Trees is that you can verify the integrity of a branch without the entire tree.
Ok, fine, I get it but how does that work in practice ?
Let's take the well known example of AWS Glacier. I give Amazon a calculated merkle tree root and the BLOB.
So far so good, but what I dont' get is how does that help Amazon verify the integrity of a portion ("branch" in Merkle-speak) of a file ?
I know that the tree root I calculated is the concatenation of various parts ? And given the tree is a concatenation of cryptographic hashes, you can't exactly extract the branches from the root hash ?
Does it work by virtue of brute-force (i.e. when you first send them the file, Amzazon calculates the branches at the point-of-receipt and then stores the hashes of those branches ad-infinitum ?) Or is it more clever than that ?
That's my point. I get the supposed benefits. I understand how you calculate the root. But I just can't fathom how you magically derive the branches from the root without going through the steps of calculating the branches first ?
I hope this is not the wrong place to ask this sort of question !