Date Added: Feb 2012
Prefix-Preserving Encryption (PPE) is an important type of encryption scheme, having a wide range of applications, such as IP addresses anonymization, prefix-matching search, and rang search. There are two issues in PPE schemes, security proof and single key requirement. Existing security proofs for PPE only reduce the security of a real PPE scheme to that of the ideal PPE object by showing their computational indistinguishability. Such security proof is incomplete since the security of the ideal encryption object is unknown. Also, existing pre x-preserving encryption schemes only consider a single encryption key, which is infeasible for a practical system with multiple users (Implying that all users should have the single encryption key in order to encrypt or decrypt confidential data).