Hi, I'm Dan Gould,

a Boston based creative developer.

Software is my medium.



The Ben-Or, Goldwasser, and Widgerson SFE Protocol


The Ben-Or, Goldwasser, and Widgerson protocol [1] allows for multi-party secure function evaluation in an environment relying on:

  • Honest but curious operation: Honest in that every party is obliged to follow the protocol. Curious in that all parties try to find out as much about the other parties as possible.[2]
  • Pairwise secure channels which exist between parties
  • Synchronous communication: Each party waits until it receives all messages for a given round before sending messages for the next round.
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Multisignature Bitcoin in C#

Bitcoin allows shared ownership of coins by using multisignature transactions.

This guide walks thorugh:

  • writing a multisignature transaction by hand
  • broadcasting it to blockchain
  • the practical applications of such a transaction
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Tal Rabin: 51% Attacks are Hard

From left to right: Zulfikar Razman, Ron Rivest, Shafi Goldwasser, Whitfield Diffie, Tal Rabin, Paul Kocher

The RSA Conference 2019 Cryptographers’ Panel was probably the most legit panel I have ever had the privilege of attending. Tal Rabin, awarded this morning the Award for Excellence in Mathematics, claimed it would cost $250,000 to 51% attack Bitcoin for 1 hour. Tal Rabin, your math is wrong! That number is actually on the order of 1000 times too small.

Likely the source of confusion: What’s $294,745 × 0? Source: crypto51.app
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