Ethereum DeAnonymisation Techniques

7 minute read

Published: July 23, 2023

Anonymize Ethereum with Bitcoin methods

Ethereum Architecture

• Ethereum stores state and account balance directly
• Smart contracts
  • Each smart contract is identified by an Ethereum address
  • Written in solidity
• Blockchain

Ethereum Overview and Privacy Attacks

8 minute read

Published: July 15, 2023

Ethereum

Accounts

• 20-byte address
• A state -> state’ = transaction of information or value between account
• Contain 4 fields
  • Nonce: Counter that make sure the transaction can be processed once
  • Ether balance
  • Contract code (for contract account)
  • Storage
• Type of accounts
  • Externally owned accounts
    • Controlled by private keys
    • Can send messages by creating and signing transaction
  • Contract accounts
    • Controlled by contract code
    • Code is activate when message is received
    • Code could read/write to internal storage or create a message or contract in return

      Contract

• An autonomous agent the live inside the Ethereum environment
• Execute a specific code when “triggered”

  Transaction and message

• Transaction- A sign data package that store a message to be sent from an externally owned account
• STARTGAS and GASPRICE are to prevent infinite loop by limiting the number of computation steps
• gas is dependent on the amount of computation and capacity of data
• Transaction contain
  • Recipient message
  • Signature of the sender
  • Amount of ether to be transfer
  • Data field(optional)
  • STARTGAS - Maximum allowed computation steps
  • GASPRICE - Fees pays by the sender per computational steps(gas)

    Messages

• Messages is like transaction except it is produced by a contract
• Messages contain the sender, recipient, amount of ether being sent, data field(optional), STARTGAS

  Ethereum state transition function

• Validate the transaction
• Calculate the transaction fee STARTGAS * GASPRICE
• Subtract the fees from the sender’s account balance and increment the sender’s nonce
• Transfer the transaction value from sender to recipient.
  • If recipient don’t exist. Create a new account
  • If it’s a contract account, run the contract’s code until completion or run out of gas
• If ran out of gas or the sender don’t have efficient fund. Revert all state changes except the payment of the fees.
• Otherwise, refund the remaining gas to the sender.
• Fees are send to the sender
• Example of transition function (Send 10eth, 2000 gas, 0.001 ether gasprice and 64 bytes of data)
  • Data being sent:
    • byte[0:31] = 2
    • byte[32:63] = “CHARLIE”

Bitcoin Transactions and Anonymity

4 minute read

Published: July 08, 2023

Content

[TOC]

Bitcoin & Blockchain Overview

5 minute read

Published: July 01, 2023

What is blockchain?

What is a block?

• Persistent, immutable and append-only data structure
• Block used as currency tracks
  • User transactions
  • Timestamp
  • Reference
• A block (besides the genesis block) is tied to it’s previous block in a cryptographic way
• Each block contains
  • Header
  • One or more user’s transactions ![Simplified Bitcoin Blockchain]