Question

Alice wants to send the contract c, which has already been signed by her, to a third party Chris for review before she receives Bob's signature. However, she does not want Chris to see that c was signed by her. Now she creates a ring signature on c. What is the purpose of creating a ring signature in this scenario?

1) To ensure the confidentiality of the contract
2) To authenticate the contract
3) To verify the integrity of the contract
4) To establish non-repudiation of the contract

Answer 1

Alice uses a ring signature to ensure the integrity of the contract and maintain her anonymity when sending it to Chris for review.

Step-by-step explanation:

Alice creates a ring signature on contract c when sending it to Chris for a review to maintain a level of anonymity. A ring signature is a type of digital signature that can be created by any member of a group of users that each have keys. The purpose of creating a ring signature in this scenario is to verify the integrity of the contract while keeping the identity of the signer (Alice) obscured from Chris. With this method, Chris can be assured that the contract has not been altered since Alice signed it, but he cannot ascertain that Alice was the actual signer, thereby achieving Alice's goal.In a ring signature, the actual signer's identity is mixed with the identities of other non-signers to form a ring, where it is computationally infeasible to determine who the actual signer is. While ring signatures provide signer ambiguity, they also ensure that no one can deny the authenticity of the signature—this is referred to as non-repudiation. However, in this particular context, the primary goal is to verify integrity while protecting Alice's confidentiality.