Association for Computing Machinery
An alibi provides evidence of a person's past location and can be critical in proving the user innocence. An alibi must be bound to a person's identity to prevent from being transferred to another person; however, requiring a person to reveal the user identity during alibi creation would compromise the person's privacy. The authors propose a privacy-preserving alibi system, where a user conceals their identity during alibi creation. The user's identity is revealed only when they chooses to present the user alibi to a judge. They design two privacy-preserving alibi schemes.