Bitcoin Anonymity Mike Fleder Mike Kester Sudeep Pillai - PowerPoint PPT Presentation

Bitcoin Anonymity Mike Fleder Mike Kester Sudeep Pillai "Voodah" "darkskypoet" 1G6EQwiAfTVyTpK4j3XZ65CvonjDGrPsQ 1QEZohXPbh4ywbzPJATjMBDnSjJsZrZtQ1

Goal & Results ● Attacker Goal ○ Tie “real” name to transactions ● Results ○ Linked forum user to Silk Road through 1 intermediaries ■ bl4kjaguar ⇒ Friend ⇒ Silk Road ⇒ FBI

What is Bitcoin? 1Agy5BVCxFHi 34nJxPdAoGh4 XLAwbdP 1LkYiL3RaouK 14hstJKLgss5 XTUhGcE84XLc UHMJqrVz8jP6 31JjnLc3 zvxN6mkuWM 1QGLRTU2KZ2b x9kJyNFGkZHy xt3VohCPCL

What is Bitcoin? Forums “voodah” 14hstJKLgss5UHMJqrVz8j Twitter P6zvxN6mkuWM “crash_override” 1Agy5BVCxFHi34nJxPdAoG h4XLAwbdP 1Agy5BVCxFHi 34nJxPdAoGh4 XLAwbdP 1LkYiL3RaouK 14hstJKLgss5 XTUhGcE84XLc UHMJqrVz8jP6 31JjnLc3 zvxN6mkuWM 1QGLRTU2KZ2b x9kJyNFGkZHy xt3VohCPCL

Security Description ● Transactions ○ Public Ledger ○ Complete history of a coin through ledger ● Software ○ Most clients imperfect

Threat Model ● Attacker Goal: Tie “real” name to transactions ● Leak 1: (“real” name, public key) revealed together ○ Intentional: Forums, donations, social networks ○ Unintentional: Inadvertent leaks Scraped from {'address':set([' 1BSmWFDn1bmmfrBZyW1hJHTwZ8apg9w99Y ']), https://bitcointalk.org/index.php?all=&topic=143194.0 'membername': [‘ cyclops ']} ● Leak 2: (“real” name, some tx info) revealed together “Alice, it’s Bob. I sent you ~$100 at ~noon yesterday”

De-anonymization Pipeline Bitcoin key ⇒ “real” names ● Leak 1: Definitively via Forums User Activity Graph Analysis Revealed ● Leak 2: Statistically via Eavesdropping

“I sent you $100 ± $1, yesterday at noon ± 5 minutes” Difficulty

Graph Analysis Pipeline “Casimir1904” Web Scraping 1BSmWFDn1bmmfrBZyW1hJHTwZ (Forums, Social media) 8apg9w99Y Block Chain User Activity Tx Graph “Entity” Graph Parser Revealed

Bitcoin “Entity” Graph PageRank Nodes Top 30 nodes 1st order edges

Bitcoin “Entity” Graph Untraceable Communities Transactions Single Entity PageRank Nodes Large Volume Top 30 nodes Transactions 1st order edges Edge thickness indicates value Typical Transaction Graph for a day

Annotated “Entity” Graph Silk Road Arrest FBI seized coins sent to a single known public key - Oct 25 2013 Revealed User Bitcointalk.org Forum user PageRank Nodes Top 30 nodes 1st order edges Annotated Nodes 40 scraped annotations

Annotated “Entity” Graph Silk Road Arrest FBI seized coins sent to a single known public key - Oct 25 2013 Revealed User Bitcointalk.org Forum user PageRank Nodes Top 30 nodes 1st order edges Thanks! Annotated Nodes 40 scraped annotations