Abstract: A method for automatically generating front-end code and back-end code that are both compatible with a specification, such as the JDWP communication protocol. First, a detailed protocol specification is written that contains a description of a communication protocol between the front-end code and the back-end code. The detailed specification is then input into a code generator that parses the specification. The front-end code is then automatically generated from the formal specification, and may be written in a first computer language such as the Java™ programming language. The code generator then generates the back-end code, which may be written in a second computer language such as C.

Abstract: In response to an inquiry by an unsophisticated Subscriber over a nonsecure network, a Provider returns a public key and retains the corresponding private key. The Subscriber encrypts a password using the public key, which is decrypted by the Provider. The password is then used to securely transfer to the Subscriber a key determined by the Provider, thereby enabling the Subscriber to decrypt messages encrypted by the Provider and transmitted over the nonsecure network. This password dependent secure transmission of a key to an unsophisticated Subscriber may be accomplished by several methods, including hashing, key lookup, Wizard protocol, and Warlock procedure. In each method the password is used by the Subscriber and the Provider in correlated operations ending in secure receipt by the Subscriber of a key determined by the Provider.

Abstract: In response to an inquiry by an unsophisticated Subscriber over a nonsecure network, a Provider returns a public key and retains the corresponding private key. The Subscriber encrypts a password using the public key, which is decrypted by the Provider. The password is then used to securely transfer to the Subscriber a key determined by the Provider, thereby enabling the Subscriber to decrypt messages encrypted by the Provider and transmitted over the nonsecure network. This password dependent secure transmission of a key to an unsophisticated Subscriber may be accomplished by several methods, including hashing, key lookup, and Wizard protocol. In each method the password is used by the Subscriber and the Provider in correlated operations ending in secure receipt by the Subscriber of a key determined by the Provider.

Abstract: Digital signal generator for producing digital signalling codes employed in a digital telephone communication system including several tone generators for providing presynthesized digital tone signals which are convertible to audible tones. Permutable digital codewords are produced by a codeword generator. Some of the tone signals and codewords are combined by FSK and switching circuitry. Tone signals, codeword signals, and combination signals are stored in storage registers and read out by a multiplexer to provide a continuous TDM bit stream of 60 channels of digital signalling codes.

Abstract: A digital receiver for receiving 8-bit permutable address code words. Before receiving each address code word the receiver must be activated by receiving five consecutive identical words of an interdigit signal of alternating 1's and 0's. The receiver must then receive the same address code word five times in succession in order to accept it. The incoming signals are applied to a 9-bit shift register. Each bit is counted by a counter, but if the bits in the first and ninth stages of the shift register are different, the counter is cleared. When the count in the counter indicates five identical 8-bit words have been received in succession and an interdigit detector detects that the word in the last eight stages of the shift register is an interdigit word, a state flip-flop is set activating the receiver.

Abstract: A TDM switching network for a communication system having 17 input transmission lines for carrying TDM digital signals in 64 input channels on each input line and having 15 output transmission lines for carrying TDM digital signals in 64 output channels on each output line. The TDM switching network establishes connections between selected input and output channels in accordance with address instructions having A and B address segments each designating a particular channel of a particular transmission line. The switching network includes 15 switching matrices (plus a spare). Each matrix is connected to all 17 of the input transmission lines and to a different one of the output transmission lines. Each switching matrix includes a data memory which can store a data bit for each channel of each transmission line. Each matrix also includes an address memory which can store an address segment for each channel of the associated output transmission line at a corresponding storage location.