bitcoins' anonymity

Download Bitcoins' anonymity

Post on 12-Apr-2017

231 views

Category:

Engineering

1 download

Embed Size (px)

TRANSCRIPT

  • Coins Anonymity2015/06/09 Mai-Hsuan Chiaj84255801912@gmail.com

    r03922099@ntu.edu.tw

    mailto:j84255801912@gmail.commailto:j84255801912@gmail.commailto:r03922099@ntu.edu.twmailto:r03922099@ntu.edu.tw

  • Abstract

    Is Bitcoin Anonymous? Solutions Projects

    Dash CryptoNote

  • Is Bitcoin Anonymous?

  • Is Bitcoin Anonymous?

    Yes!! Due to the fact that addresses are segregated from ids.

  • Is Bitcoin Anonymous?

    Yes!! Due to the fact that addresses are segregated from ids.

    No, because

  • Is Bitcoin Anonymous?

    Transaction Linkage

  • Is Bitcoin Anonymous?

    Transaction Linkage Forward Change Linking

  • Is Bitcoin Anonymous?

    Transaction Linkage Through Change Linking

  • Is Bitcoin Anonymous?

    Fingerprinting timestamp, , ,

  • Is Bitcoin Anonymous?

    Fingerprinting timestamp, , ,

    Alice, I will give you 1.5 btc tomorrow!

    OK, Thank you

  • Is Bitcoin Anonymous?

    Fingerprinting timestamp, , ,

    Alice, I will give you 1.5 btc tomorrow!

    OK, Thank you

  • Is Bitcoin Anonymous?

    Mantissa Attack

  • Is Bitcoin Anonymous?

    Mantissa Attack

  • Solutions

    CoinJoin Ring Signature Teleport, Coin shuffle, ...

  • Solutions

    CoinJoin : coins

  • Solutions

    CoinJoin : coins

  • Solutions

    CoinJoin Dark Wallet : a Bitcoin wallet client Dash ( Darkcoin )

  • Solutions

    Ring Signature

  • Solutions

    Ring Signature

  • Solutions

    Ring Signature CryptoNote ( implemented by Bytecoin, Monero,...)

  • Projects

    Dark Wallet Dash CryptoNote Tor

  • Projects

    Dark Wallet A Bitcoin wallet client, dark wallet users

    CoinJoin

  • Dash Altcoin POW x11 hash algorithm InstantTx DarkSend using CoinJoin

  • DarkSend DarkSend pool Master node Collatoral transactions and payment nodesDarkSend pool

    0.1, 1, 10, 100, mixing1000DASH mixing 1 session

  • DarkSend DarkSend pool Master node Collatoral transactions and payment nodesMaster nodes

    coinjoin txbroadcast Master Nodepool

  • DarkSend DarkSend pool Master node Collatoral transactions and payment nodesPayment nodes

    mixingusers payment nodedarksend pool pool

  • DarkSend

  • DarkSend : masternodecoinjoin

    inputoutput

  • CryptoNote Technology that allows the creation of completely

    anonymous egalitarian cryptocurrencies Egalitarian PoW Adaptive limits

    Difficulty adjusted every block Dynamic Max block size

    Ring Signature

  • Ordinary signature

    Ring signature

  • Untraceable Transactions

  • Linkable tx

    Unlinkable tx

  • one-time keypairs SenderReceiverone-time

    pubkeyone-time pubkeyreceiverone-time privkey

    One-time pubkeyrandom datareceiver address *One-time privkeyrandom datareceiver privkey

    (der) CryptoNotereuse address

    unique one-time pubkey receiverone-time privkey

  • one-time keys

  • one-time keys For example,1. Baddressb_addr2. AB, b_addrrandom data

    one-time pubkey3. Bone-time privkey4. txB(output

    unique one-time pubkey)5. Btxtrytx

  • *Prevention from double spending output(output)

    spenderoutputdouble spending

    one-time privkeyhashkey imageinput userskey image

    key imagedouble spendreject

  • one-time ring signatures operations SIG (sign)

    input : message, other pubkeys, (mypubkey, myprivkey) output : a signature, all pubkeys

    VER (verify) input : message, all pubkeys, signature output : true or false

    ...

  • CryptoNote :

  • CryptoNote : blockchain size

    e.g. Bitcoin v.s. MoneroElapsed time Blockchain size # of transactions

    Bitcoin 5 years 20GB 43,000,000

    Monero 3 months 2 GB 170,000

  • Reference

    https://cryptonote.org/inside/https://cryptonote.org/whitepaper.pdfTeleport: anonymity through off-blockchain transaction information transferhttps://www.dashpay.io/wp-content/uploads/2014/09/DarkcoinWhitepaper.pdfhttps://www.dashpay.io/wp-content/uploads/2015/04/Dash-WhitepaperV1.pdf

    https://cryptonote.org/inside/https://cryptonote.org/inside/https://cryptonote.org/whitepaper.pdfhttps://cryptonote.org/whitepaper.pdfhttps://www.dashpay.io/wp-content/uploads/2014/09/DarkcoinWhitepaper.pdfhttps://www.dashpay.io/wp-content/uploads/2014/09/DarkcoinWhitepaper.pdfhttps://www.dashpay.io/wp-content/uploads/2014/09/DarkcoinWhitepaper.pdfhttps://www.dashpay.io/wp-content/uploads/2015/04/Dash-WhitepaperV1.pdfhttps://www.dashpay.io/wp-content/uploads/2015/04/Dash-WhitepaperV1.pdfhttps://www.dashpay.io/wp-content/uploads/2015/04/Dash-WhitepaperV1.pdf