| 摘要 |
A system for the retrieval of confidential information in which an entered password is allowed to contain some erroneous or invalid characters and still be considered acceptable to access confidential information without compromising the security of the information retrieval system. The characters of a set of passwords, sequentially entered, are mapped to Galois Field elements with the mapping table constructed sequentially, and uniquely for each user of the system, such that the mapped Galois Field elements for each password are equal to a codeword of a defined error correcting code and this codeword is associated with a message containing encrypted confidential information. Any password used to retrieve confidential information messages is mapped to Galois Field elements using the same constructed mapping table and error correction decoded to produce a codeword of the error correcting code. Any encrypted information message associated with this codeword is decrypted and output from the system. If the codeword is not associated with encrypted confidential information the system may output a message to this effect such as the message "password invalid". The security of the information retrieval system arises from the fact that the number of possible codewords of a typical error correcting code is extremely large and in one example described in the invention there are 10<612> possible codewords of which only a small number, typically less than 100, are associated with any encrypted information. Applications of the invention include in wireless networks, such as an information retrieval service provided by a mobile phone operator. |
