Abstract: Apparatus and techniques described herein can include a load circuit comprising a direct current (DC) input terminal, and a source circuit comprising a direct current (DC) output terminal coupled to the DC input terminal of the load circuit. The source circuit can include a source control circuit configured to provide a current-limited DC output voltage and monitor the current-limited DC output voltage to detect an authentication signal provided at the DC output terminal by the load circuit, the load circuit configured to modulate the voltage at the DC output terminal using a pull-down circuit. The load circuit can be configured to compare the supply voltage at the DC input terminal to a reference voltage and, in response, energize other portions of the load circuit when the input current provided the DC input terminal is sufficient as indicated at least in part by the comparison.

Abstract: Apparatus and techniques described herein can include a load circuit comprising a direct current (DC) input terminal, and a source circuit comprising a direct current (DC) output terminal coupled to the DC input terminal of the load circuit. The source circuit can include a source control circuit configured to provide a current-limited DC output voltage and monitor the current-limited DC output voltage to detect an authentication signal provided at the DC output terminal by the load circuit, the load circuit configured to modulate the voltage at the DC output terminal using a pull-down circuit. The load circuit can be configured to compare the supply voltage at the DC input terminal to a reference voltage and, in response, energize other portions of the load circuit when the input current provided the DC input terminal is sufficient as indicated at least in part by the comparison.

Abstract: A method and apparatus for protecting access to sensitive information stored in vulnerable storage areas (e.g., public memory, registers, cache) of a microprocessor. A microprocessor having a reset port to receive external reset commands may have a reset diversion circuit that may be selectively enabled. The microprocessor may operate in an open mode or a secure mode, indicating the absence or the potential presence, respectively, of sensitive information in the vulnerable storage areas. In open mode, the reset diversion circuit may be disabled such that external reset requests triggers a hardware reset. In secure mode, sensitive information may be recorded on vulnerable storage areas. The reset diversion circuit may be enabled to divert external reset requests to an interrupt which may trigger execution of a software code. The software code, when executed, may perform a secured system clean-up routine to erase the vulnerable storage areas prior to reset.

Abstract: A method and apparatus for protecting access to sensitive information stored in vulnerable storage areas (e.g., public memory, registers, cache) of a microprocessor. A microprocessor having a reset port to receive external reset commands may have a reset diversion circuit that may be selectively enabled. The microprocessor may operate in an open mode or a secure mode, indicating the absence or the potential presence, respectively, of sensitive information in the vulnerable storage areas. In open mode, the reset diversion circuit may be disabled such that external reset requests triggers a hardware reset. In secure mode, sensitive information may be recorded on vulnerable storage areas. The reset diversion circuit may be enabled to divert external reset requests to an interrupt which may trigger execution of a software code. The software code, when executed, may perform a secured system clean-up routine to erase the vulnerable storage areas prior to reset.

Abstract: A microprocessor to provide software development debugging capabilities while providing security for confidential and/or sensitive information. The processor may operate in one of an open, a secure entry, and a secure mode. In open mode, security measures may prevent access to certain registry bits and access to a private memory area. Secure entry mode may be entered upon receipt of a request to run secure code and/or access the private memory area. The secure code may be authenticated in secure entry mode. Authentication may be performed using digital signatures. Secure mode may be entered if authentication is successful. Authenticate code may be executed in the secure mode environment. The private memory area may be accessible in secure mode.