Method and apparatus for encrypting data
AssigneeF-Secure Oyi
InventorAri Huttunen
Life of this patent
Estimating the term…
Abstract
A method of securing data on an electronic device comprises allowing a user of the device to select one of an encryption and decryption operating mode and an encryption only operating mode. The encryption and decryption operating mode requires that the device have access to a user passphrase, and the encryption only operating mode does not require that the device have access to the passphrase.
Claims16
A method of securing data on an electronic device and comprising:
- allowing a user of the device to select one of an encryption and decryption operating mode and an encryption only operating mode, wherein,
- the encryption and decryption operating mode requires that the device have access to a user passphrase, and the encryption only operating mode does not require that the device have access to the passphrase.
A method of securing data stored on an electronic device whereby access to the secured data requires the entry of a user passphrase, the method comprising:
- encrypting the data using a symmetric cipher and corresponding symmetric key (KEYtmp) which is accessible without the need for the passphrase, storing the encrypted data and destroying the unencrypted data;
- and
- destroying the plaintext form of the symmetric key, whilst storing the symmetric key (KEYtmp)in an encrypted form protected by said passphrase so that, immediately following the encryption of the data, the unencrypted key (KEYtmp) is unavailable to the device until the passphrase is subsequently available to the device.
An electronic device comprising hardware and/or software for causing the device to operate in one of two operating modes, an encryption and decryption operating mode and an encryption only operating mode, the encryption and decryption operating mode requiring that the device have access to a user passphrase, and the encryption only operating mode does not require that the device have access to the passphrase.
A computer program storage medium having stored thereon a computer program for causing a computer device to:
- allow a user of the device to select one of an encryption and decryption operating mode and an encryption only operating mode, wherein, the encryption and decryption operating mode requires that the device have access to a user passphrase, and the encryption only operating mode does not require that the device have access to the passphrase.
A method of securing data stored on an electronic device, the method comprising:
- 1) pre-generating a plurality of symmetric keys for use with a symmetric cipher;
- 2) storing the keys in a memory of the device in a plaintext form and in an encrypted form, the encrypted form being protected by a user passphrase;
- 3) encrypting a block of data using one of said symmetric keys;
- 4) storing the encrypted block and destroying the plaintext version;
- 5) destroying the plaintext version of the key used to encrypt the block;
- and
- 6) repeating steps 3) to 5) for each subsequent block to be encrypted,
- wherein the encrypted blocks are secured until such time as a user enters the passphrase to unlock the encrypted versions of the used symmetric keys.
Dependencies are inferred from the claim text.