PrivateBid

Bid privately. Verify publicly.

A privacy-preserving sealed-bid procurement platform built with Midnight.

PrivateBid enables organizations to run digital procurement auctions where bid values remain confidential while the final outcome can be verified.

Live Demo · GitHub

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Why PrivateBid?

Traditional online procurement has a fundamental problem:

How do you prove that an auction was fair without exposing every bidder's price?

In conventional systems, bid information is typically stored by a centralized platform. This creates several risks:

• Competitors may gain access to sensitive pricing information.
• Late bidders can strategically undercut earlier bids.
• A compromised database can expose confidential tenders.
• Participants must trust the platform operator to honestly execute the auction.
• Auditors can verify the final result only by trusting the underlying system.

For infrastructure contracts and high-value procurement, bid confidentiality is not a feature — it is part of the integrity of the process.

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The Solution

PrivateBid is a privacy-preserving sealed-bid auction framework for digital procurement.

The core idea is simple:

             TRADITIONAL AUCTION

     Bid A ─────┐
     Bid B ─────┼──> Public / Centralized System
     Bid C ─────┘
                       │
                       ▼
                Sensitive prices
                     exposed


                  PRIVATEBID

     Bid A ─────┐
     Bid B ─────┼──> Private computation
     Bid C ─────┘          │
                           ▼
                    Verified result
                           │
                           ▼
                Winning result public
                Losing bids private