Abstract: A mobile communication system for designating a specific location and for selecting a call destination is provided. A server stores and manages the locational information (latitude and longitude) for the individual mobile stations. When each of the mobile stations transmits, to the server, mail including the designation of the locational range for a communication partner and other information to be provided, the server uses the locational information of the mobile stations and the range included in the mail (latitude and longitude at the center, and radius) to determine whether the location of a pertinent mobile station falls within the designated range, and thus obtains the user names of all the mobile stations present in the range. When there are too many mobile stations in the range, the server reduces the number of mobile stations and selects mobile stations based on user attributes. The server then transmits, to the thus selected mobile stations, mail including the information to be provided.

Abstract: Content data is judged to determine whether data prepared by a digital device were altered by performing an authentication process using a medium on which content data are recorded; reading the content data from the medium; embedding, in the content data, data for verifying the pertinent content; extracting, from the content data, the data for verifying the pertinent contents; using the results of the extraction to determine whether the content data were altered. Preferably, the means includes means for identifying any portion containing altered data.

Abstract: Alternate methods, devices and systems are presented for providing service providers and/or end users of mobile stations to monitor and/or report regions with high error rates and/or dead zones. A protocol is provided such as to yield the error occurrence, error rate and/or the address of the end user. In some embodiments it also contains location information and time of day information. This information may be collected from the G.P.S., and/or all or a portion of users when there is a significant transmission difficulty and/or an abundance of errors. The collected data forms a database which is analyzed to generate coverage maps. This may include the dynamic aspects of the mobile network. In another aspect of this invention, each mobile station periodically compares its current location with the data base. The results of this comparison enables the mobile unit to anticipate connection problems.

Abstract: The present scheme improves the security of encrypted data or information by using of a practical public-key cryptosystem that is able to resist adaptive attacks. The disclosed scheme does not leak any information about the secret of the used key. Therefor the scheme generates an extended private key and public key. A message m, also referred to as plaintext, is encryptable to a ciphertext t by using the public key. Only a recipient with the right private key is able to decrypt the ciphertext r. But before a decryption starts, a verification of the ciphertext t takes place. Such a verification allows to prove the legitimation of the ciphertext t. That means, the ciphertext t is investigated and either decrypted back to the plaintext or rejected if a chosen ciphertext is fed, ie. the ciphertext is illegitimate or invalid.