Page 125 - Kaleidoscope Academic Conference Proceedings 2021

Connecting physical and virtual worlds

Figure 3 – Schematic diagram of contract signing based on randomness beacon.

generated by the beacon coincides at + Δ with the random she discloses the secret to Bob, she will get his receipt .
number at that they agreed upon. The probability of As shown in Figure 4, the randomness beacon service
this event occurring is 1/ . This is a smart contract signing repeatedly generates a random number , a series of
agreement that allows to avoid one of the parties to override encryption keys ( 1 , · · · , ) and a decoding key =
their commitment with a small probability of failure 1/ , ( ( −1) with period , and broadcast the signature
depending on the range of random numbers generated by the message ( 1 , · · · , , , 0 + Δ ) at 0 + Δ , where f is the
randomness beacon service. number of repetitions ( = 0, 1, 2, · · · ). Alice and Bob start
With a proper design of the randomness beacon service and communication at the initial time 0 . To execute the protocol,
potential improvements to the smart contract, the failure Alice encodes with Bob’s public key B, plus her own
probability can be reduced and the efficiency can be increased. encryption key , producing the result = ( ( )).
In addition, the service provider of a stochastic beacon They agree on a random number 0 , which Alice uses to
does not have access to any contract and does not receive select the 0 ℎ encryption key in ( 01 , · · · , 0 ) issued by
information about the transaction. She/he only broadcasts the beacon at 0 time. Alice encrypts her decryption key
one-way signed random numbers to the public. Thus, her/his ( ) with the key 0 , i.e., 0 ( ( )). After Bob sends the
liability is limited and can support decentralized Internet signed receipt ( , 0 , 0 +/ ) to Alice (the signature
protocols. can be verified by the other party), she then sends the signed
message of the cryptodecoding key ( ) to Bob along with
4.2.2 Confidential disclosure , 0 and 0 . They also repeat the procedure with a
cycle. For the honest party, if the other party does not send
A randomness beacon protocol can solve the problem of the required messages in the corresponding period, or if the
confidential disclosure in the absence of a trusted third party random number and the key they use during
[30]. Consider the case where Alice, the custodian of a starting at time 0 + Δ , which matches the random number
personal document database, agrees to disclose a confidential , the decoding key ( ) issued by the beacon at the
content to Bob. We assume that Alice is responsible time 0 + Δ . For the latter case, Bob can decode ( ( ))
for the authenticity of , and Bob agrees to keep it to obtain ( ), and then decode by ( ) and ( ) to
confidential. Let denote the actual string of secrets, obtain .
referred to by the number . Alice must be sure that when Bob is considered committed to receive in 0 + / time

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