MimbleWimble coins (BEAM, Grin) vs. PIRATE (ARRR)

A technical comparison between the long anticipated implementations of MimbleWimble called BEAM & Grin and the upcoming private cryptocurrency PIRATE.

Published in

Pirate Chain

6 min readJan 28, 2019

ATTENTION: Convert Pirate funds to Sapling before 10 February: https://dexstats.info/pirateswap.php

Welcome to the 5th installment of the “Pirate VS. series”. This is a special one as we host the TWO recent MimbleWimble implementations called BEAM and Grin.

A lot of anticipation has been going toward the release of MimbleWimble privacy coins and let’s see if they live up to the hype!

Pirate (ARRR) vs. MimbleWimble (BEAM, Grin)

Mimblewimble: Confidential transactions

MimbleWimble is a much anticipated protocol as it received quite some attention and hype around BEAM and Grin.

The protocol prevents the blockchain from expelling personal information like the addresses used and amounts sent, hence the name “MimbleWimble”.

MimbleWimble combines a modified version of Confidential Transactions originating from Shen Noeter to hide amounts and “one-way aggregate signatures” (OWAS) originating from Dr. Yuan Horas Mouton in order to combine transactions.

This cut-through feature, which merges transactions when an output is directly spent by the input of another, makes MimbleWimble implementations more scalable on-chain than Bitcoin. Only a small piece of data called a kernel (about 100 bytes) needs to stay around for each transaction and 3 kB per unspent output. This decreases blockchain storage needed.

There are 2 main properties of MimbleWimble that should make usage of MimbleWimble coins private:

There are no addresses visible on the blockchain.
There are no amounts visible on the blockchain.

Check out BEAM’s block explorer HERE as an example.

This feature is much like Pirate transactions where addresses are shielded and no amounts are visible on the blockchain as well.

Private by default

Furthermore, like with Pirate, transactions conducted by the MimbleWimble protocol are private by default which is vital for fungibility of the coins and anonymity of the users.

A big thumbs up for that!

BEAM or Grin?

BEAM and Grin are different in their tokenomics. BEAM aims to stimulate development through the implemention of a 20% block reward founders fee, while Grin is dependent on community efforts and the sale of merch for instance. The emission schedule of the coins differ between both projects as well:

BEAM

Decreasing block rewards:

100 BEAM in the first year, then 50 BEAM, 25 BEAM etc. per 4 years.

1 minute block time
20% founders fee
A capped supply at 262. 8 Million BEAM.
Consensus algo: Equihash PoW
Programmed in C++

Funny detail: BEAM’s are denominated in 100.000.000 Groth, named after Jens Groth, a renowned computer scientist, and cryptographer who laid some of the groundwork for zero-knowledge proofs the privacy technology used in PIRATE!

Grin

Constant block reward of 60 Grin.
1 minute block time
No founders fee.
No capped supply (!)
Consensus algo: Cuckoo Cycle PoW
Programmed in Rust

Is MimbleWimble all rainbows and sunshine?

Certainly not, a large disadvantage of MimbleWimble is that in order to finalize the transaction and thereby receive BEAM or Grin, both parties of the transaction need to show their IP-address and an open port when sending from wallet to wallet. This is quite inconvenient (you are not always online to receive a transaction) and leaves room for attack vectors.

Solutions to transact without being online at the same time:

There are alternative channels to transact offline with BEAM or Grin such as BEAM’s Secure Bulletin Board System (SBBS) which requires to share an encrypted message directed to the receiver containing their public key through a chosen channel, which then decrypts it using the known key from the channel.

Grin uses slates which is a method needing the exchange of a transaction file between sender and receiver requiring 3 operations and 2 message exchanges. With both you are sharing encrypted metadata and anonymity in Grin offline depends on the medium the transaction file is shared.

The MimbleWimble protocol itself is non-interactive as it doesn’t need other transactions as much as the original CoinJoin protocol for privacy, but the way transactions are finalized is very much interactive as nodes to to be online to receive transactions or have to perform actions online, not necessary both at the same time.

Now enough of the MimbleWimble magic, let’s go over to Pirate shall we, Arrr!

PIRATE

PIRATE (ARRR) is an assetchain (independent blockchain) out of the Komodo ecosystem which makes it based on Zcash tech, but with privacy by default which has been determined by the parameters set in the Komodo assetchain

Zcash uses specific zero-knowledge proofs called zk-SNARKs (zero-knowledge succinct non-interactive arguments of knowledge) which allows transaction data to be validated without revealing ANY information about the amounts and the parties involved when transacting between shielded addresses. Furthermore, the transacting parties do not need to be online to receive and confirm the transaction. The technology relies on a “Trusted setup”, however with the coming of the “Sapling” upgrade and with that the “Powers of Tau”, the probability of collusion virtually impossible. See “Powers of Tau Ceremony”.

Riccardo “fluffypony” Spagni, one of Monero’s core team members even openly stated zk-SNARKS provide stronger untraceability characteristic than Monero (Confidential Transactions).

PIRATE: The first Sapling only blockchain

What makes PIRATE unique is that it’s a forced shielded-transactions only blockchain utilizing zk-SNARKS technology (z-transactions) the best privacy tech there is and its chain is protected by the Bitcoin hashrate through delayed Proof-of-Work. PIRATE is mined into a transparent address, but can only go into a shielded address from there. The result of this feature is that all of ARRR is shielded, dramatically increasing the fungibility and anonymity of the usage of the blockchain for sending funds. Furthermore, PIRATE supports TOR to obfuscate geographic location (IP).

Technical characteristics of Pirate (ARRR)

Blocktime: 60 seconds
Mining algorithm: Equihash PoW
dPoW security
Transaction fee: 0.0001 ARRR
Capped supply at 200 million ARRR
Transactions per second: 34 TPS max.
Tx size: 2kb-200 kb.
Ability to send to 100 addresses simultaneously in one transaction.
PIRATE supports TOR to obfuscate geographic location (IP)

A big advantage of Pirate compared to MimbleWimble coins is that transactions are finalized on the blockchain without the need of the receiving party being online.

A big hurdle thus far for Zcash (and thus its forks) has been the development of Simple Payment Verification for shielded addresses (zSPV). When this is developed into completion however, it would mean one of the only large disadvantages of zk-SNARKS would be eliminated.

Conclusion

MimbleWimble coins and Pirate all provide privacy by default which is a BIG advantage for all three when it comes to privacy and anonymity.

A large drawback to MimbleWimble implementations however is the interactive nature of the finalization of the transactions. The need for your node to be online combined with revealing the IP-address hurts privacy and security.

PIRATE has the edge in anonymity and security but MimbleWimble has an advantage in scalability for now.

Both protocols can be improved in terms of usability:

PIRATE in developing light wallets with z-address functionality and MimbleWimble in making transaction finalization non-interactive and more secure.

Thanks for reading and follow the links for more info about Pirate and MimbleWimble!

Cheers!

Flexatron

Reference links

https://medium.com/beam-mw/mimblewimbletechnologies/home

https://explorer.beam.mw/blocks

https://docs.beam.mw/Mimblewimble.pdf

https://github.com/mimblewimble/grin/blob/master/doc/grin4bitcoiners.md

https://github.com/mimblewimble/grin/blob/master/doc/intro.md