Mixing

Anonimityの提供。Value uniformな性質によりconfidentialityは提供しない。

Universalで単一なmixingを使うことでanonimity setの増加に繋がる

Deposit時間が長いほどanonimity増加

brand newなaddressが引き出すのでfee代払い必要

秘匿送金ではなくコインのLinkabilityを切りたいユースケース(?)で利用

https://gyazo.com/b42242adf4b4bc6a5f74227d20f215e9

CoinJoin

n inputs & n outputsの1つのbitcoin txを協力して生成

central serverによるcencorship resistanceの懸念。

Coinshuffle

CoinJoinの分散バージョン

複雑かつコスト高なoff-chain protocol

Mobius

初のeth contracts上のmixier

引き出し時にlinkable ring signature

ring signature検証のonchain cost、it grow linearly in the size of the anonimity set. (50~100)

Miximus

snarksによるmerkle pathの検証

MixEth

Neff verifiable shuffleを使って参加者の公開鍵をmix

A Verifiable Secret Shuffle and its Application to E-Voting

k-anonimity(plausible deniability)のためには複数回のround tripsが必要でtime-intensive。

引き出し時にはbrand newな自身のアドレスが引き出すがgas feeを持っていないのでtrusted 3rd partiyにfee払いを頼るかそのアドレスにfunding (k-anonimityが低減）

ShareLock

threadhold ECDSA-based mixier

ECDSA signature has a known malleability: For every valid signature σ = (r, s) the signature σ? = (r, −s) is also a valid signature. In our protocol we will require unique signatures. We can achieve it by either mandating that min{s, q − s} is always output and verify rejects if s > q 2 or we can output an extra bit v to determine which is the correct signature.

ECDSA:

malleability: (r, -s) could be also valid signature

EU-CMA

https://gyazo.com/349924fa1f966eb444ad5f65d3c61422

Ethereum

Tornado cash. Non-custodial private transactions on Ethereum.

https://gyazo.com/82c2a3f36cbb6492de94c41c1aa66503

Using Relayer or not, you still need to keep up common Internet anonymity like using vpn, proxies, Tor in order to hide the IP address you act from. Since you are using browser an Incognito Tab feature is also useful.

Make sure you clear cookies for dapps before using your new address, because if a dapp sees both old and new address with the same cookies it will know that addresses are from the same owner.

Proof of concept integration of Zerocash on Ethereum

M¨obius: Trustless Tumbling for Transaction Privacy

Bitcoin

Mixcoin: Anonymity for Bitcoin with accountable mixes

Use a series of mixies

Uniform transactions - all mix transaction have same value

Client side must be automated

Fees must be all-or-nothing :

An Inquiry into Money Laundering Tools in the Bitcoin Ecosystem

ShareLock: Mixing for Cryptocurrencies from Multiparty ECDSA