Storage medium and method and apparatus for separately protecting data in different areas of the storage medium

• US 20050251866A1
• Filed: 06/27/2005
• Published: 11/10/2005
• Est. Priority Date: 03/18/1998
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Uchida, Yoshiaki, Kobayashi, Hiroyuki
• Application Number:
  US11/167,638
• Publication Number:
  US 20050251866A1
• Time in Patent Office: Days
• US Class Current: 726/27
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00

Abstract

Disclosed are a method and an apparatus for protecting data on a storage medium by encrypting the data to be recorded on the storage medium with a password. This method comprises a step of, generating, for changing key data on each memory unit by one password, the key data, thereafter encrypting the key data with the password and writing the encrypted data to the storage medium, and a step of encrypting the data with the key data and encrypted data to the storage medium. The method further comprises a step of reading the encrypted key data from the storage medium, a step of decoding the encrypted key data with the password, and a step of decoding the data on the storage medium with the decoded key data. The encryption is done by using the key data generated separately from the password, and it is therefore feasible to prevent the password from being analyzed by decoding a cipher text.

Claims

1. -20. (canceled)

21. A storage medium data protecting method of protecting data on a storage medium comprising:

a step of generating a random key, encrypting said random key with a password, and writing said encrypted random key to the storage medium;

a step of encrypting the data with the generated random key, and writing the encrypted data to the storage medium;

a step of reading said encrypted key from the storage medium;

a step of decoding said encrypted key with said password; and

a step of decoding the data on the storage medium with the decoded key,

wherein said writing said encrypted random key to the storage medium comprises a step of encrypting said random key with each of a plurality of passwords, writing said encrypted random keys to the storage medium, and said step of decoding the encrypted key comprises a step of decoding said encrypted key with a designated password.

22. A storage medium data protecting method of protecting data on a storage medium comprising:

a step of generating a random key, encrypting said random key with a password, and writing said encrypted random key to the storage medium;

a step of encrypting the data with generated random key, and writing the encrypted data to the storage medium;

a step of reading said encrypted key from the storage medium;

a step of decoding said encrypted key with said password; and

a step of decoding the data on the storage medium with the decoded key,

wherein said writing said encrypted random key to the storage medium comprises a step of encrypting said random key with a first password, writing the encrypted random key to the storage medium, encrypting said first password with a second password, and writing the encrypted first password to the storage medium, and

said step of decoding the encrypted key comprises a step of decoding said encrypted first password with said second password, and obtaining said first password, and a step of decoding said encrypted key with said obtained first password.

23. A storage medium data protecting apparatus for protecting data, comprising:

a storage medium having a plurality of unit storage areas; and

a control circuit for reading and writing the data from and to said storage medium,

wherein said control circuit has;

a write mode of encrypting, after generating a random key, said random key with a password, writing said encrypted random key to the storage medium, encrypting the data with the generated random key, and writing the encrypted data to the storage medium; and

a read mode of decoding, after reading said encrypted key from the storage medium, said encrypted key with said password, and decoding the data on the storage medium with the decoded key,

wherein said write mode has a mode of encrypting said random key with each of a plurality of passwords, writing said encrypted random keys to the storage medium, and

said read mode has a mode of decoding the encrypted key comprises a step of decoding said encrypted key with a designated password.

24. A storage medium data protecting apparatus for protecting data, comprising:

a storage medium having a plurality of unit storage areas; and

a control circuit for reading and writing the data from and to said storage medium,

wherein said control circuit has;

a write mode of encrypting, after generating a random key, said random key with a password, writing said encrypted random key to the storage medium, encrypting the data with the generated random key, and writing the encrypted data to the storage medium; and

a read mode of decoding, after reading said encrypted key from the storage medium, said encrypted key with said password, and decoding the data on the storage medium with the decoded key,

wherein said write mode has a mode of encrypting said random key with a first password, writing the encrypted random key to the storage medium, encrypting said first password with a second password, and writing the encrypted first password to the storage medium, and

said read mode has a mode of decoding said encrypted first password with said second password, and obtaining said first password, and a step of decoding said encrypted key with said obtained first password.

25. -26. (canceled)

27. A storage medium data protecting method of protecting data on a storage medium comprising:

a step of generating a random key, encrypting said random key with a password, and writing said encrypted random key to the storage medium;

a step of encrypting the data with the generated random key, and writing the encrypted data to the storage medium;

a step of reading said encrypted key from the storage medium;

a step of decoding said encrypted key with said password; and

a step of decoding the data on the storage medium with the decoded key,

wherein further comprising;

a step of decoding, after reading said encrypted key from the storage medium, the said encrypted key with an old password designated by a user; and

a step of writing, after encrypting said decoded key with a new password designated by said user, the encrypted key to the storage medium.

28. A storage medium data protecting apparatus for protecting data, comprising:

a storage medium having a plurality of unit storage areas; and

a control circuit for reading and writing the data from and to said storage medium,

wherein said control circuit has;

a write mode of encrypting, after generating a random key, said random key with a password, writing said encrypted random key to the storage medium, encrypting the data with the generated random key, and writing the encrypted data to the storage medium; and

a read mode of decoding, after reading said encrypted key from the storage medium, said encrypted key with said password, and decoding the data on the storage medium with the decoded key,

wherein said write mode further comprises a mode of decoding, after reading said encrypted key from the storage medium, the said encrypted key with an old password designated by a user, and writing, after encrypting said decoded key with a new password designated by said user, the encrypted key to the storage medium.