Method for encrypting and decrypting metadata
A method of encrypting metadata that can be represented by a tree structure. The method involves generating an encryption key for a predetermined node of the metadata using a function that takes as input parameters an encryption key for an upper node of the predetermined node and information specifying the predetermined node, and encrypting data of the predetermined node using the generated encryption key.
1. A method of encrypting metadata that is represented by a tree structure, comprising:
generating an encryption key for a predetermined node of the metadata using a function that takes as input parameters an encryption key for an immediately-preceding upper node of the predetermined node and information specifying the predetermined node at a processor of a user device and encrypting data of the predetermined node using the generated encryption key; and
storing the encrypted data at a metadata storing unit,
wherein the information specifying the predetermined node is position information of the predetermined node in the tree structure.
2. The method of claim 1 , wherein the function is a one-way function.
3. The method of claim 1 , wherein the information specifying the predetermined node is relative position information.
4. The method of claim 1 , wherein the information specifying the predetermined node is absolute position information.
5. The method of claim 1 , wherein the function is a hash function.
6. The method of claim 1 , wherein the encrypted data comprises attribute values corresponding to the predetermined node.
7. A method of decrypting metadata that is represented by a tree structure, comprising:
generating a key for a predetermined node of metadata received from a metadata storing unit using a function that takes as input parameters a key for an immediately-preceding upper node of the predetermined node and information specifying the predetermined node at a processor of a user device, the generating the key being performed at a decryption unit; and
decrypting data of the predetermined node using the generated key,
wherein the information specifying the predetermined node is position information of the predetermined node in the tree structure.
8. The method of claim 7 , wherein the function is a one-way function.
9. The method of claim 7 , wherein the information specifying the predetermined node is relative position information.
10. The method of claim 7 , wherein the information specifying the predetermined node is absolute position information.
11. The method of claim 7 , wherein the function is a hash function.
12. The method of claim 7 , wherein the decrypted data comprises attribute values corresponding to the predetermined node.