Abstract: A system and method for encrypting data provides for retrievial of an encryption key; identification of the address in memory of a first portion of the data to be encrypted; derivation of a first unique key from the encryption key and the address of the first portion of data; encryption of the first portion of data using the first unique key; identification of the address in memory of a second portion of data to be encrypted; derivation of a second unique key from the encryption key and the address of the second portion of data; and encryption of the second portion of data using the second unique key.

Abstract: A system and method of creating and managing encryption keys in a data processing device generates subsequent encryption keys by combining the existing encryption key with an existing password and seed value. In the preferred embodiment, the initial encryption key is embedded during manufacture and is unknown to the user and manufacturer, thus ensuring that all subsequent encryption keys are derived from an unknown value. When a subsequent encryption key is generated, all data encrypted using the existing encryption key is decrypted using the existing encryption key and re-encrypted using the subsequent encryption key before the existing encryption key is overwritten. In a further aspect, during encryption/decryption the encryption key is combined with the sector address of the data to be encrypted/decrypted in order to generate a unique key for each sector of data to be encrypted/decrypted.

Abstract: A system and method of creating and managing encryption keys in a data processing device generates subsequent encryption keys by combining the existing encryption key with an existing password and seed value. In the preferred embodiment, the initial encryption key is embedded during manufacture and is unknown to the user and manufacturer, thus ensuring that all subsequent encryption keys are derived from an unknown value. When a subsequent encryption key is generated, all data encrypted using the existing encryption key is decrypted using the existing encryption key and re-encrypted using the subsequent encryption key before the existing encryption key is overwritten. In a further aspect, during encryption/decryption the encryption key is combined with the sector address of the data to be encrypted/decrypted in order to generate a unique key for each sector of data to be encrypted/decrypted.

Abstract: A clock signal duty cycle control circuit is provided that receives an incoming signal from a clock signal input source and generates an improved output clock signal having an accurately controlled duty cycle. The circuit controls the duty cycle of the output clock signal by comparing the incoming signal to a reference value in a comparator. The reference value is derived from a reference charge stored on a capacitor. The reference charge is built up in the capacitor using the currents from a current source and a current sink, which are controlled using translated output signals from the comparator.

Abstract: A clock signal duty cycle control circuit is provided that receives an incoming signal from a clock signal input source and generates an improved output clock signal having an accurately controlled duty cycle. The circuit controls the duty cycle of the output clock signal by comparing the incoming signal to a reference value in a comparator. The reference value is derived from a reference charge stored on a capacitor. The reference charge is built up in the capacitor using the currents from a current source and a current sink, which are controlled using translated output signals from the comparator.

Abstract: A clock signal duty cycle control circuit is provided that receives an incoming signal from a clock signal input source and generates an improved output clock signal having an accurately controlled duty cycle. The circuit controls the duty cycle of the output clock signal by comparing the incoming signal to a reference value in a comparator. The reference value is derived from a reference charge stored on a capacitor. The reference charge is built up in the capacitor using the currents from a current source and a current sink, which are controlled using translated output signals from the comparator.