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US 6,378,072 B1Granted
Cryptographic system
AssigneeCompaq Computer Corporation
InventorsThomas Collins, John Gregory, Ralph Bestock
Life of this patent
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Abstract
A cryptographic system and method for encrypting and decrypting data using public key cryptography. The encryption and decryption may be divided into tasks that may operate in parallel. A secure method of initializing the cryptographic system to allow for secure operations and protect against tampering with application software. The application program is retrieved from an encrypted file in external memory and authenticated before being executed.
Claims6
A cryptographic system comprising:
- a bus interface for transferring data between the cryptographic system and an external source;
- a processor, the processor receiving data from the bus interface, and constructing from the data a plurality of exponentiation tasks;
- a plurality of exponentiation units, the processor transferring each of the plurality of exponentiation tasks to a corresponding one of the plurality of exponentiation units so that the plurality of exponentiation tasks can be performed substantially in parallel by the plurality of exponentiation units in order to speed up system operations, and the plurality of exponentiation units returning results of the plurality of exponentiation tasks to the processor;
- and
- initialization means operatively coupled to the processor and configured to place the cryptographic system in a secure state after system reset and allow execution of a secure program, but prior to each execution the secure program is verified and authenticated via the processor.
2 more elements
A method of initializing a cryptographic system, comprising:
- decrypting by the cryptographic system an encrypted packet with a load program to create an original load program;
- authenticating and validating the original load program;
- and
- if the original load program is determined to be a secure load file and is authenticated, placing the cryptographic system in a secure mode, and
- authenticating a secondary loader program, wherein the secondary loader program can be customized for a user by placing a personalized key in a table, and wherein the secondary loader program is configured,
- in response to a load command from the cryptographic system, to allow a user program to be loaded and stored in memory if the user program is authenticated, the user program being signed by a private key corresponding to the personalized key that is known only to the user, and
- in response to a start command from the cryptographic system, to execute the stored user program if it is authenticated;
- each time the cryptographic system is initialized upon power up, if the system is initialized in a secure mode, generating cryptographic keys, including the first decryption key, from seed values held securely in the cryptographic system.
5 more elements
Dependencies are inferred from the claim text.