Talk:Merkle tree

message: Hi! I am thinking of merging the Tiger-Tree Hash article into a subsection of Hash tree. Please respond here if you have any comments.
--David Göthberg 02:03, 26 August 2005 (UTC)
replies: text: Sounds appropriate because a Tiger-Tree hash is just a hash tree hash with fixed choices for the block size and hash function (if I understand correctly?). — Matt Crypto 01:04, 28 August 2005 (UTC)
replies: text: Yes, you understand correctly. A Tiger tree hash is just a hash tree with fixed choices for the block size (1024 bytes), hash function (Tiger) and type of tree (binary). He, I just realised I should perhaps mention in the article that a hash tree can be of other types then binary. Each node can have much more child nodes then two. (Although binary is the most popular since at least in theory it is the most flexible.) For instance in my own system I am thinking of using lots of children for each node in such a way that the tree only has two levels. Like this: Data blocks, first level hashes, second level hashes, top hash. Sort of just a hash list with an extra level, easier to implement but still means you can download a "branch" at a time. (That is, download the first level hashes, check the integrity of them, then download a chunk of second level hashes that fits under one single hash in the first level and check the integrity. Then start downloading blocks that corresponds to that chunk of second level hashes.) --David Göthberg 11:45, 29 August 2005 (UTC)

text: I think a merge would be ok, as TTH is rather short and is the only notable implentation of a hash I know. Just be careful to maintain a boundary between concept and implementation and this should be no problem. --R.Koot 19:46, 28 August 2005 (UTC)
replies: text: Yep, done so.  --David Göthberg 11:45, 29 August 2005 (UTC)
thread_title:  Merge of Tiger-Tree Hash into Hash tree 

message: Several things seem to have confused editors and some readers. Since I don't know how to make them more clear in the article without making the text to heavy I will explain them here so future editors at least have access to the info.
* Hash trees doesn't have to be binary. That is, they can have more than two child nodes/leaves under each node. But binary hash trees seems to be the most used nowadays. One can just as well for instance have a tree with 100 child nodes/leaves under each node. Then if you use 100 bytes per hashed data block and have a file of say 1 million bytes that means two levels of hashes below the top hash. Like this: Top hash < 100 hashes < 100*100 hashes < 100*100 hashes * 100 bytes per block = 1 million bytes.
* The sentences about Lamport signatures and quantum computers seem to have caused a lot of confusion and edits. I have kept them short in the article since that is currently not an important issue and should probably instead be explained more in detail in the Lamport signature article. Lamport signatures are in them self already secure against quantum computers since they do not use the kind of maths that other public-key systems use, instead they only use hashes. Good strong hashes are believed to not be affected by quantum computers. You just need to use slightly bigger hashes than we use today. The bad part is that a Lamport signature can only be used once. So your published "public-key" can only be used one time. So if you want to sign many messages you would have to publish a long list of one time public Lamport keys. That would be awkward. But if you hash all those Lamport public keys with a hash tree you can then instead publish just the top hash! And when signing a message all you have to store in the message is the signature and the hash tree "branch" of hash nodes that makes it possible to verify the hashes up to the top hash. So hash trees doesn't make Lamport signatures more secure or change them, hash trees "just" makes it possible to easily handle MANY Lamport signatures.
* Some editors have added "citation needed" tags on the page or asked about the source of some of the statements. Well, all the sources needed are already right there in the external links section. Those links go to good sources that explains pretty much all the details about hash trees and the RSA labs article also explain why Lamport signatures are secure against quantum computers. (The article is written and published by RSA labs, it is not a Wikipedia article.) And I think RSA labs is one of the more trusted sources we have when it comes to crypto stuff. Many other sources I have seen also claims that quantum computers do not seriously affect hashes and stream/block ciphers. Just that public-key systems like RSA, DH, ECC etc are affected.
* Note that this article doesn't tell the full story about hash trees. There are many more things one need to understand to implement and use hash trees in a cryptographically secure way. But that would make this article huge. Currently the article is just an introduction to hash trees. Again the external links section points to documents telling most of the details and that is why I put a sentence in the text that mentions that: "There are several additional tricks, benefits and details regarding hash trees. See the external links below for more in-depth information."
* Tiger tree hashes are just a specific kind of hash tree. And currently the most used ones. There is nothing special about them using Tiger hashes. Tiger is just another hash function and Tiger in itself has nothing special to do with hash trees. It just so happens that when hash trees started to be used in p2p networks the p2p programmers did choose Tiger as the hash. They could just as well have chosen any other cryptographically secure hash.
--David Göthberg 06:23, 18 October 2006 (UTC)
thread_title:  Some clarifications 

message: I am proposing a merge of Hash tree (persistent data structure) into Merkle tree. 
* Merge - They're referring to the same thing, a trie where elements are stored by hashcode.  --Padenton (talk) 22:48, 10 March 2015 (UTC)
thread_title:  Merger Proposal [[Hash tree (persistent data structure)]] 

message: Yo there!
I am half-oatmeal brained right now from other things, but that's only making things normal :8). Reading through a couple of screens multiple times produced not a clue about hash trees yet - and I need something concise. This article seems to totally fail ... in other words I feel it would be a complete waste of time to pursue it any further - and that I need to find a better teacher. 
The subject complexity is not a problem for me, generally. And, even if it means creating a long story -- it should be engaging with bite-sized bits to digest.
Xgenei (talk) 02:12, 23 September 2015 (UTC)
thread_title:  Failure to Explain 

message: Hello fellow Wikipedians,
I have just modified one external link on Merkle tree. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive https://web.archive.org/web/20070317045032/http://www.codeproject.com/cs/algorithms/thexcs.asp to http://www.codeproject.com/cs/algorithms/thexcs.asp
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
Cheers.—InternetArchiveBot (Report bug) 06:30, 26 January 2018 (UTC)
thread_title:  External links modified (January 2018) 

message: UC Berkeley. Nicholas Spooner nick.spooner@berkeley.edu. UC Berkeley. October 25https://eprint.iacr.org/2019/1076.pdf  — Preceding unsigned comment added by Waterwizardm (talk • contribs) 08:31, 9 July 2020 (UTC)
thread_title:  Related sources (zkSnark)