ELI5: MimbleWimble

What is MimbleWimble and what are its benefits? Explained like you’re five.

James Webber
Nov 11, 2018 · 5 min read

MimbleWimble is a very complex protocol that greatly affects the scalability and privacy of a cryptocurrency. By saying it greatly affects, it means it definitely brings tremendous improvements to a cryptocurrency, particularly to Bitcoin.

Bitcoin has a lot of problems. It is not surprising since Bitcoin is considered a prototype of what a perfect currency functions like. Yes, it possesses privacy safeguards; but some problems are currently overlooked and might bring unsolvable issues to the network and to its users. Some people provide bright solutions, one of it is MimbleWimble — a solution (or rather a revolutionary feature) to Bitcoin’s growing privacy and scalability issue.

Explain like I’m five: MimbleWimble

I’ll introduce to you a bright and large group of friends (let’s inconveniently call them d’hodlers) and their smart friend librarian named Noddy (nodes). This group of friends prioritizes privacy — they don’t want others to know what they are doing and what they are into.

D’hodlers has this very very secret book which can only be borrowed in a particular library. To make things worse, it is only one in the library. They need to devise a way to secure the book only to themselves. They need to confer with Noddy that all the borrowers of the book are indeed part of the D’hodlers and only the intended borrower within the group as well.

Instead of writing the borrowed time and date on the slip found in the book, they have written a special code at the upper part (header) of the slip. Using the code, the person needs to write their entry with time and date (value), their name (from), and the next intended borrower (to). Added security is each entry affects the next entry (invalid previous entry results in an invalid next entry!) Each entry is validated by Noddy, and each new entry is written at the next line of the previous entry (this is the blockchain).

Each borrower can choose a member of the group to be the next borrower. He can assure it by creating another code (called Blinding Factor) that the original borrower (from) and the next borrower (to) only know. The next borrower will apply the Blinding Factor to the entry he will write thus 1. retains the integrity of the chain of entries and codes, and 2. proving the he is legitimate next borrower.

Since each entry takes a space, each borrower needs to write the entries from beginning down to their own entry in a new paper slip (the old paper slip is always discarded per use). This was not an issue in the beginning but the code goes longer and longer and nobody wants to borrow the book anymore!

Tom Elvis Jedusor (a genius member of D’hodlers) saw this issue of this lines of entry getting bigger and bigger. He also thought that by running down the series of entries, anyone can be exposed by verifying the sender and receiver though the series of entries — even by outsiders (via Pedersen Commitment scheme)! He thought of the risks and found a way to get rid of these: he thus called this MimbleWimble.

Instead of writing all individual entries, he will just need to write a one big entry (called CoinJoin or one multisignature) on the slip by combining the code, all entries into one. In this way, he lets himself, the last borrower, and all of the future borrowers to be concealed. He also cut the time one must consume to write and borrow the book. Even Noddy doesn’t need to know who are and what time the book has been turned in (but since the integrity of the blockchain is intact, he can confidently assumes that all transactions are remain valid).

For the legitimate next borrower, the receiver (to) generates the Blinding Factor instead. The receiver also produces random numbers (Dummy Output) alongside the Blinding Factor, which is communicated to and written also by the original borrower (from) on the slip. This is to ensure the next borrower is the person who generated the blinding factor, and can stay in the line of entries as validated by Noddy (when the next borrower is ready to lend it to the next borrower).

The slip is now bounded by the number of borrowers, not by the number of times the book is borrowed.

That’s it. Tom reduces the time it takes to write and keep a code, heightens the privacy of the borrowers, and strengthens the integrity of the line of entries, which is the blockchain.

The explanation written here is overly simplified. If you want read more about MimbleWimble, there are lots of articles found on the net or you can read the whitepaper here.

Why is it not implemented in Bitcoin?

However, its compatibility with Bitcoin protocol (note: not with all cryptocurrency) is a bit problematic. For MimbleWimble to work, the whole script must be purged from all transactions. That’s why MimbleWimble with its current form is fit for privacy-focused sidechain.

MoneroV, a coin made for privacy and scalability

MoneroV has seen the problems will arise in Monero in the long run — a high transaction costs and big blockchain size that users will ultimately suffer. MoneroV has solved this by hardforking from Monero and implementing one of the innovative features: MimbleWimble protocol.

As mentioned, MoneroV blockchain will be bound to the number of users, not the number of transaction size made in the network.

This is a huge leap for cyptocurrencies. The first in the run is Grin Coin (Running in Rust) which also aims to be scalable, has no addresses, no amounts, and less storage than its counterparts.

With the power of original Monero blockchain and MimbleWimble, MoneroV certainly and covers the problems before these arise, proving MoneroV as one of the coins that will last in the long run. For starters, visit MoneroV website here or read the MoneroV whitepaper here.

Questions and Suggestions?

Leave your comments below!


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