Deriving a symmetric key from an asymmetric key for file encryption or decryption
First Claim
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1. A method comprising:
- accessing a private key of an asymmetric key pair in a key device;
deriving a symmetric master key from the private key of the asymmetric key pair; and
storing the symmetric master key in a computer memory location, wherein files can be encrypted or decrypted in response to the symmetric master key.
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Abstract
One aspect relates to a process and associated device that provides a private key of an asymmetric key pair in a key device. A symmetric master key is derived from the private key of the asymmetric key pair. The symmetric master key is stored in a computer memory location. The symmetric master key is used to encrypt or decrypt a file encryption key. The file encryption key can encrypt or decrypt files. In another aspect, the user can still access the files even if a user deactivates the key device by encrypting or decrypting the file encryption key directly from the symmetric master key.
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Citations
42 Claims
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1. A method comprising:
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accessing a private key of an asymmetric key pair in a key device;
deriving a symmetric master key from the private key of the asymmetric key pair; and
storing the symmetric master key in a computer memory location, wherein files can be encrypted or decrypted in response to the symmetric master key. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A computer readable medium having computer executable instructions for performing steps comprising:
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providing a private key of the asymmetric key pair in a key device;
deriving a symmetric master key from the private key of the asymmetric key pair using a hash function; and
storing the symmetric master key in a computer memory location that encrypts or decrypts a file encryption key, wherein the file encryption key can encrypt or decrypt files. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. An apparatus comprising:
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a signature memory space;
a signature device that signs the data with the signature; and
a symmetric master key device for creating the symmetric master key using prescribed bits of the signature.
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29. A method comprising:
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accessing a known string;
deriving a symmetric master key from the known string; and
storing the symmetric master key in a computer memory location, wherein files can be encrypted or decrypted using the symmetric master key. - View Dependent Claims (30, 31, 32)
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33. A file sharing method, comprising:
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a first user encrypting or decrypting a file based on a file encryption key, wherein the file encrypting key is encrypted or decrypted based on a symmetric master key model;
the first user requesting to add a second user to the file;
the first user adding a second user by obtaining the second user'"'"'s public key, and then encrypting of decrypting the file encryption key using the second users public key. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41)
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42. One or more electronically-accessible media comprising electronically-executable instructions that, when executed, direct an electronic device to perform actions comprising deriving, from a private key of an asymmetric key pair, a symmetric key to be used for file encryption or decryption.
Specification