Verifiable Broadcast

Party:

uses UDP, ECDSA

has all public keys of other parties

has its own private key

n - total nodes. t - potential malicious nodes

• wait message from client
• receive message, sign
• send signed message to client
• receive (n+t+1)/2 signs from client -> check -> commit

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Reliable Broadcast

Party

uses UDP

n - total nodes. t - potential malicious nodes

• waits for message from client
• sends echo{message, nonce} to other parties
• waits for echos:
  • received (n+t+1)/2 echo messages and not sent ready -> send ready{message, nonce} to other parties
• waits for readies:
  • received t+1 ready messages and not sent ready -> send ready{message, nonce} to other parties
  • received 2t+1 ready messages -> commit