Dan Boneh

Session Logistics and Participants

• Four speakers were scheduled for 15-minute slots each, totaling approximately 60 minutes of presentation time.
• A 15-minute Q&A session was planned for 10:10 AM, followed by a break and an industry conversation session starting at 10:30 AM.
• The moderator introduced speakers covering Bitcoin/blockchain, healthcare device security, malware analysis, and cloud privacy.
• The moderator noted their own company was acquired earlier that year.

Bitcoin Market Context and Blockchain Research

• Bitcoin's market capitalization stabilized at approximately $3.5 billion within the last six months, following a peak in mid-2013.
• Bitcoin is identified as the first cryptocurrency to achieve significant adoption, transitioning from experimental attempts to a functional network.
• Stanford launched course CS251 on blockchain technologies, utilizing lab infrastructure built by the startup 21 (funded by Andreessen Horowitz).
• Course materials and lab projects regarding Bitcoin mining and applications are open for adoption by other universities.

Proof of Solvency for Bitcoin Exchanges

• Research addressed the solvency verification problem exposed by the Mt. Gox exchange failure, aiming to prove assets exceed obligations without third-party auditors.
• The solution employs zero-knowledge proofs to allow exchanges to prove solvency without revealing internal business details or specific asset balances.
• The protocol involves three steps: committing to total obligations, committing to total assets, and mathematically proving assets exceed obligations.
• Step 1 utilizes cryptographic commitments to sum customer obligations; customers can verify their specific balance is included in the commitment using a secret key.
• Step 2 leverages Bitcoin's public blockchain by selecting a large set (e.g., one million) of random public keys to prove the exchange owns a specific subset where the sum of balances matches the asset commitment.
• This approach allows an exchange to prove ownership of assets without revealing which specific public keys are owned or the total asset count.
• The proof generation time is approximately 10 minutes per day; a full verification takes 40 minutes, though partial verification by customers is sufficient.
• The resulting proof data is approximately 1 gigabyte for an exchange with 500,000 customers, which the presenter deemed manageable for cloud storage.
• The system requires daily publication of proofs; failure to generate a proof would publicly indicate a solvency issue.

Technical Assessment of AES and Hardware Security

• The presentation on Control Flow Integrity was skipped due to time constraints.
• Intel's hardware implementation of AES (Advanced Encryption Standard) in x86 processors has drastically reduced evaluation costs.
• AES performance on Intel architecture improved from 7 cycles per round on Haswell to 4 cycles on Skylake, with a projected reduction to 2 cycles within two years.
• The presenter concluded that hardware acceleration makes AES computationally "free" compared to software implementations.
• This hardware dominance is predicted to hinder the adoption of alternative block ciphers, as they cannot compete with AES's software-in hardware efficiency.

Stanford Cyber Initiative

• The Cyber Initiative is a grant-funded project from the Hewlett Foundation focusing on the integration of technology into society.
• The initiative seeks to host events and discussions on ethics of data collection, the privacy-security trade-off, and data ownership rights.
• Researchers and industry professionals were invited to participate in or speak at these upcoming events.