Showing papers on "Client-side encryption published in 1991"

File encryption method and file cryptographic system

Abstract: In an information processing system having an upper rank apparatus and an external storage device which performs transmission and reception of data between the storage device and the upper rank apparatus, at least one of encryption and decryption of the data by use of an algorithm controlled by a desired data key is performed in the external storage device, while generation, encryption and decryption of the data key are performed on the upper rank apparatus side. By this configuration, the burden of the upper rank apparatus is largely reduced and the secrecy of data stored in the external storage device can be surely kept without spoiling the throughput of the whole system.

Secured data storage devices

Abstract: A device for storing user data and a value representative of the time of storage is disclosed, which includes physically separating portions of an encryption key, combining a time stamp with user data, and using the restored encryption key to encrypt and decrypt the stamped user data.

Generic encryption technique for communication networks

Abstract: A method and related cryptographic processing apparatus for handling information packets that are to be cryptographically processed prior to transmission onto a communication network, or that are to be locally cryptographically processed and looped back to a node processor. A special cryptographic preamble is included in each information packet that is to be subject to cryptographic processing. The cryptographic preamble contains an offset value pointing to the starting location of information that is to be processed, and completely defines the type of cryptographic processing to be performed. The cryptographic processor can then perform the processing as specified in the preamble without regard to a specific protocol. If the packet is to be transmitted onto the network, the preamble is stripped from the packet after cryptographic processing, so that the formats of packets transmitted onto the network will be unaffected by the preamble. Cryptographic processing modes include encryption of data for outbound transmission, encryption of a cipher key for loopback to the node processor, encryption or decryption of data for loopback to the node processor, and computation of an integrity check value for loopback to the node processor.

Remote key manipulations for over-the-air re-keying

Abstract: A method of remotely changing an original voice encryption key in a secure radio (10) is provided which includes a central controller (20) transmitting to the secure radio a digital word (42) representing a selective operation to be performed on the original voice encryption key stored in the radio (10). In response to the digital word (42), the radio (10) performs the operation on the original voice encryption key to generate a current voice encryption key.

Automatic encryption selector

Abstract: A radio (100) capable of automatically selecting an encryption algorithm from among a plurality of algorithms (122 and 124) is disclosed. The method for automatically selecting the proper encryption hybrid includes the steps of: attempting to decrypt the encrypted signal with one of the plurality of encryption algorithms; determining if the encryption algorithm used to decrypt the encrypted signal matches the encryption algorithm used by the encrypted signal; and developing a control signal upon the proper matching of the encryption algorithms.

Signalling scheme for controlling data encryption device in an electronic fund transaction processing system

Abstract: An improved method for communicating with a data encryption device is described. In accordance with this invention, a data encryption device adapted for providing encryption functions such as data encryption and decryption may be controlled with an inventive signalling protocol which provides two-way, symmetrical messaging. Data encryption messages are sent to a data encryption device with a message packet which includes a start of message character, a token field, a token dependent data field, a token delimiter and an end of message character. Once the requested data encryption function is performed, a response message is generated wherein the response message mirrors the request message with the exception that the token dependent data comprises data which was processed in accordance with the requested function. The method of the present invention is also adapted for loading key information in the data encryption device as well as communicating system status information.

Facsimile message encryption system

Abstract: A system for maintaining the security of information transmitted between facsimile machines includes a transmitting/receiving facsimile machine for receiving input sheets having an encryption zone; an image sensor for detecting the encryption zones; an encryption device for scrambling messages that appear within an encryption zone. Further the system includes means for sensing encryption zones on transmitted messages and for decoding messages that have been scrambled within the encryption zones.