Calculation device and calculation method
First Claim
1. An arithmetic unit comprising:
- a data input interface configured to input data to be subjected to arithmetic processing for at least one of encryption, decryption, or key generation;
a command input interface configured to input a command for specifying processing on said data;
an arithmetic processor configured to subject the data inputted by said data input interface to arithmetic processing;
a data output interface configured to output the data processed by the arithmetic processor;
an output selector configured to select data to be outputted from the data output interface; and
a controller configured to control said output selector such that only data allowed to be outputted is outputted from said data output interface on the basis of the command inputted by said command input interface.
1 Assignment
0 Petitions
Accused Products
Abstract
An arithmetic unit and an arithmetic method that output no information necessary for decryption or encryption to the outside and can perform a self-protecting function when an illegal attack is made. A command monitoring part (44) monitors input command sequences. In a first sequence, a process key in a first stage is calculated from a hardware key (Khd) and is then written to a key storing part (47). In each of the following sequences, a process key in a next stage is calculated from a process key stored in the key storing part (47). When commands of predetermined contents are inputted in predetermined order, a content key is calculated and then written to the key storing part (47). Encrypted data is decrypted with the content key, and the result is outputted from data output means (63). When an illegal attack is made, initialization is performed by selecting fixed value data (Kf) as key data (Ksl) and selecting fixed value data (Df) as input data (Ein).
4 Citations
14 Claims
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1. An arithmetic unit comprising:
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a data input interface configured to input data to be subjected to arithmetic processing for at least one of encryption, decryption, or key generation; a command input interface configured to input a command for specifying processing on said data; an arithmetic processor configured to subject the data inputted by said data input interface to arithmetic processing; a data output interface configured to output the data processed by the arithmetic processor; an output selector configured to select data to be outputted from the data output interface; and a controller configured to control said output selector such that only data allowed to be outputted is outputted from said data output interface on the basis of the command inputted by said command input interface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An arithmetic method comprising the steps of:
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performing arithmetic processing on input data on the basis of an input command to generate at least one of encrypted data, decrypted data, or an key; determining whether the input command specifies output of an encryption or decryption result of the arithmetic processing; and outputting the result of the arithmetic processing on said input data when the input command specifies the output of the result of the arithmetic processing. - View Dependent Claims (13, 14)
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Specification