The paper "Secure Conjunctive Keyword Search over Encrypted Data" by Philippe Golle, Jessica Staddon, and Brent Waters addresses the challenge of securely searching for encrypted documents that meet multiple keyword criteria. The authors propose a security model for conjunctive keyword search and present two schemes to enable such searches. The first scheme has linear communication complexity in the number of documents but can be computed offline, relying on the Decisional Diffie-Hellman (DDH) assumption. The second scheme has communication complexity proportional to the number of keyword fields and relies on a new hardness assumption. The paper highlights the limitations of existing solutions, such as set intersection and meta-keywords, which either allow the server to learn sensitive information or require exponential storage. The proposed solutions aim to provide a more secure and efficient way to perform conjunctive keyword searches on encrypted data, making them a crucial building block for effective document retrieval in untrusted environments.The paper "Secure Conjunctive Keyword Search over Encrypted Data" by Philippe Golle, Jessica Staddon, and Brent Waters addresses the challenge of securely searching for encrypted documents that meet multiple keyword criteria. The authors propose a security model for conjunctive keyword search and present two schemes to enable such searches. The first scheme has linear communication complexity in the number of documents but can be computed offline, relying on the Decisional Diffie-Hellman (DDH) assumption. The second scheme has communication complexity proportional to the number of keyword fields and relies on a new hardness assumption. The paper highlights the limitations of existing solutions, such as set intersection and meta-keywords, which either allow the server to learn sensitive information or require exponential storage. The proposed solutions aim to provide a more secure and efficient way to perform conjunctive keyword searches on encrypted data, making them a crucial building block for effective document retrieval in untrusted environments.