Oblivious Transfer
Web3 / privacy technology
Oblivious Transfer is a foundational cryptographic protocol where a sender possesses multiple pieces of information and transfers exactly one of them to a receiver based on the receiver's choice, while remaining completely oblivious to which piece was selected. The receiver obtains their chosen information with certainty, but the sender cannot determine what was transferred. This seemingly paradoxical guarantee—the receiver knows exactly what they got while the sender doesn't—is achieved through careful use of public-key cryptography and probabilistic techniques. Oblivious Transfer serves as a building block for more complex privacy-preserving protocols including secure multi-party computation and serves fundamental roles in cryptographic protocols across numerous applications. Example: The Yao's Millionaires' Problem, a classic secure computation scenario where two millionaires want to determine who is richer without revealing their actual wealth, uses oblivious transfer as a core component in its cryptographic solution to enable private comparison. Why it matters for privacy technology: Oblivious Transfer enables secure computation between untrusting parties in Web3 environments. It allows users to access decentralized services and data without providers learning their queries, essential for private DeFi interactions, confidential voting systems, and sealed-bid auctions on public blockchains.
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