<p>Public-key encryption with keyword search (PEKS) is a well-known method for privacy-preserving keyword search in encrypted email systems due to its public-key characteristics. However, we have observed that even without a keyword-search trapdoor, traditional PEKS allows the server to distinguish ciphertexts effectively, compromising semantic security. To address this limitation, we introduce dynamic searchable public-key encryption (DSPE), a concept that conceals relationships between searchable ciphertexts and their corresponding encrypted files, ensuring semantic security in both theory and practice. DSPE also enables the server to delete specific ciphertexts as requested by the receiver. We present a DSPE instance with provable semantic security in the random oracle model, which offers the advantage of sublinear complexity in identifying matching ciphertexts and deleting intended ones. Through experimental validation, we demonstrate the feasibility of this instance. Furthermore, we construct a DSPE-based cloud email system in the double-cloud model and evaluate its performance.</p>

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Dynamic searchable public-key encryption and its application

  • Min Han,
  • Peng Xu,
  • Willy Susilo,
  • Wei Wang

摘要

Public-key encryption with keyword search (PEKS) is a well-known method for privacy-preserving keyword search in encrypted email systems due to its public-key characteristics. However, we have observed that even without a keyword-search trapdoor, traditional PEKS allows the server to distinguish ciphertexts effectively, compromising semantic security. To address this limitation, we introduce dynamic searchable public-key encryption (DSPE), a concept that conceals relationships between searchable ciphertexts and their corresponding encrypted files, ensuring semantic security in both theory and practice. DSPE also enables the server to delete specific ciphertexts as requested by the receiver. We present a DSPE instance with provable semantic security in the random oracle model, which offers the advantage of sublinear complexity in identifying matching ciphertexts and deleting intended ones. Through experimental validation, we demonstrate the feasibility of this instance. Furthermore, we construct a DSPE-based cloud email system in the double-cloud model and evaluate its performance.