Keyword query method based on hierarchical attributes under cloud environment

The invention discloses a keyword query method based on hierarchical attributes under a cloud environment, and the method comprises the following steps: a data owner encrypts a data file set with a preset attribute hierarchy tree and an encryption parameter, wherein a leaf node attribute of a second access tree is a lower attribute of the attribute hierarchy tree and is used for encrypting a keyword; a trustable third party distributes an attribute set to a new user and generates a decryption key and a search key; all attributes in the attribute are all from the attributes in the attribute hierarchy tree; the new user generates a search token according to the search key and a to-be-searched keyword; a cloud performs matching judgement for each keyword according to the search token, if a matched keyword ciphertext exists, a file ciphertext corresponding to the keyword ciphertext is sent to the new user; and the file ciphertext is decrypted by the decryption key. By constructing the attribute hierarchy tree, a