Abstract:
Two-speed bidirectional, closed loop stepping motor control is obtained, utilizing only a single feedback encoding device. The feedback signals are combined logically with suitable input controls and suitable acceleration and deceleration pulse sources, to provide the type of operation required. The system operation comprises acceleration to low speed, acceleration to high speed, change from low speed to high speed, change from high speed to low speed, and a stopping sequence from any speed. The stop signal may occur at random with no loss of motor control.
Abstract:
A stepping motor drive which includes both a closed loop feedback control system and an open loop oscillator control system. The stepping motor is started by a start pulse, and feedback pulses from an emitter driven by the motor are gated to accelerate the motor. At the same time, the feedback pulses are gated to reset and synchronize a free-running oscillator. Feedback and oscillator pulses are compared, and when synchronism is achieved, i.e., the motor is up to speed, the oscillator pulse gate drive is enabled. When this occurs, the oscillator is controlled by a discriminator which compares the phase of the oscillator and feedback pulses and corrects the relation therebetween by modifying the oscillator frequency.
Abstract:
Single step operation of a stepping motor and deceleration of the stepping motor utilized in a closed-loop mode are obtained utilizing a pulse injection arrangement in which a suitable plurality of pulses are supplied in rapid succession to the drive circuits for the stepping motor in order to quickly step the magnetic fields to the proper condition at a rate too fast for the rotor to follow.
Abstract:
Arrangements are disclosed for validating that key management functions requested for a cryptographic key by the program have been authorised by the originator of the key. The invention includes a cryptographic facility characterised by a secure boundary through which passes an input path for receiving the cryptographic service requests, cryptographic keys and their associated control vectors, and an output path for providing responses thereto. There can be included within the boundary a cryptographic instruction storage coupled to the input path, a control vector checking unit and a cryptographic processing unit coupled to the instruction storage, and a master key storage coupled to the processing means, for providing a secure location for executing key management functions in response to the received service requests. The cryptographic instruction storage receives over the input path a cryptographic service request for performing a key management function on a cryptographic key. The control vector checking unit has an input coupled to the input path for receiving a control vector associated with the cryptographic key and an input connected to the cryptographic instruction storage, for receiving control signals to initiate checking that the control vector authorises the key management function which is requested by the cryptographic service request. The control vector checking unit has an authorisation output connected to an input of the cryptographic processing means, for signalling that the key management function is authorised, the receipt of which by the cryptographic processing unit initiates the performance of the requested key management function with the cryptographic key. The invention enables the flexible control of many cryptographic key management functions in the generation, distribution and use of cryptographic keys, while maintaining a high security standard.
Abstract:
MA988-011 of the Invention SECURE MANAGEMENT OF KEYS USING CONTROL VECTORS The invention is an apparatus and method for validating that key management functions requested for a cryptographic key by the program have been authorized by the originator of the key. The invention includes a cryptographic facility characterized by a secure boundary through which passes an input path for receiving the cryptographic service requests, cryptographic keys and their associated control vectors, and an output path for providing responses thereto. There can be included within the boundary a cryptographic instruction storage coupled to the input path, a control vector checking unit and a cryptographic processing unit coupled to the instruction storage, and a master key storage coupled to the processing means, for providing a secure location for executing key management functions in response to the received service requests. The cryptographic instruction storage receives over the input path a cryptographic service request for performing a key management function on a cryptographic key. The control vector checking unit has an input coupled to the input path for receiving a control vector associated with the cryptographic key and an input connected to the cryptographic instruction storage, for receiving control signals to initiate checking that the control vector authorizes the key management function which is requested by the cryptographic service request. The control vector checking unit has an authorization output connected to an input of the cryptographic processing means, for signalling that the key management function is authorized, the receipt of which by the cryptographic processing unit initiates the performance of the requested key management function with the cryptographic key. The invention enables the flexible control of many cryptographic key management functions in the generation, distribution and use of cryptographic keys, while maintaining a high security standard.