Method and system for depositing private key used in RSA cryptosystem
First Claim
1. A method for depositing a private key used in an RSA cryptosystem, comprising the steps of:
- dividing a private key of a user into a first partial private key and a second partial private key at a user'"'"'s entity, where the first partial private key is set to be maintained at the user'"'"'s entity;
depositing the second partial private key from the user'"'"'s entity to another entity;
delivering the second partial private key from said another entity to the user'"'"'s entity in response to a request from the user'"'"'s entity; and
composing the first partial private key maintained at the user'"'"'s entity and the second partial private key delivered from said another entity so as to obtain the private key to be used in a processing according to the RSA cryptosystem at the user'"'"'s entity.
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Accused Products
Abstract
A scheme for depositing a private key used in the RSA cryptosystem which is capable of maintaining the private key more safely, without requiring a user to always carry around a storage medium. In this scheme, a private key of a user is divided into a first partial private key and a second partial private key at a user'"'"'s entity, where the first partial private key is set to be maintained at the user'"'"'s entity, while the second partial private key is deposited from the user'"'"'s entity to the other entity. Then, the second partial private key is delivered from the other entity to the user'"'"'s entity in response to a request from the user'"'"'s entity, and the first partial private key maintained at the user'"'"'s entity and the second partial private key delivered from the other entity are composed so as to obtain the private key to be used in a processing according to the RSA cryptosystem at the user'"'"'s entity. This scheme can be generalized to a case of dividing the private key into a plurality of partial private keys.
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Citations
30 Claims
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1. A method for depositing a private key used in an RSA cryptosystem, comprising the steps of:
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dividing a private key of a user into a first partial private key and a second partial private key at a user'"'"'s entity, where the first partial private key is set to be maintained at the user'"'"'s entity; depositing the second partial private key from the user'"'"'s entity to another entity; delivering the second partial private key from said another entity to the user'"'"'s entity in response to a request from the user'"'"'s entity; and composing the first partial private key maintained at the user'"'"'s entity and the second partial private key delivered from said another entity so as to obtain the private key to be used in a processing according to the RSA cryptosystem at the user'"'"'s entity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for depositing a private key used in an RSA cryptosystem, comprising the steps of:
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dividing a private key of a user into a plurality of partial private keys at a user'"'"'s entity, where one of said plurality of partial private keys is set to be maintained at the user'"'"'s entity; depositing remaining ones of said plurality of partial private keys from the user'"'"'s entity to mutually different ones of other entities respectively; delivering the remaining ones of said plurality of partial private keys from the other entities to the user'"'"'s entity in response to a request from the user'"'"'s entity; and composing said one of said plurality of partial private keys maintained at the user'"'"'s entity and the remaining ones of said plurality of partial private keys delivered from the other entities so as to obtain the private key to be used in a processing according to the RSA cryptosystem at the user'"'"'s entity. - View Dependent Claims (15)
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16. A system for depositing a private key used in an RSA cryptosystem, comprising a user'"'"'s entity and another entity, wherein the user'"'"'s entity includes:
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a private key dividing unit for dividing a private key of a user into a first partial private key and a second partial private key, where the first partial private key is set to be maintained at the user'"'"'s entity; a key depositing unit for depositing the second partial private key to said another entity; a partial private key acquisition unit for requesting a delivery of the second partial private key to said another entity and receiving the second partial private key delivered from said another entity; and a private key composition unit for composing the first partial private key maintained at the user'"'"'s entity and the second partial private key delivered from said another entity so as to obtain the private key to be used in a processing according to the RSA cryptosystem. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A system for depositing a private key used in an RSA cryptosystem, comprising a user'"'"'s entity and other entities, wherein the user'"'"'s entity includes:
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a private key dividing unit for dividing a private key of a user into a plurality of partial private keys, where one of said plurality of partial private keys is set to be maintained at the user'"'"'s entity; a key depositing unit for depositing remaining ones of said plurality of partial private keys to mutually different ones of the other entities respectively; a partial private key acquisition unit for requesting a delivery of the remaining ones of said plurality of partial private keys to the other entities and receiving the remaining ones of said plurality of partial private keys delivered from the other entities; and a private key composition unit for composing said one of said plurality of partial private keys maintained at the user'"'"'s entity and the remaining ones of said plurality of partial private keys delivered from the other entities so as to obtain the private key to be used in a processing according to the RSA cryptosystem. - View Dependent Claims (30)
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Specification