Document encryption and decryption method, device and system

The invention discloses a document encryption and decryption method, device and system. The document encryption and decryption method comprises the steps of receiving an electronic document downloading request sent by a client side; generating an encryption secret key, encrypting file content corresponding to a document identifier by utilization of the encryption secret key, and generating an encrypted document; reading a stored user public key according to user information, and encrypting the encryption secret key to generate secret key information by utilization of the user public key; correspondingly storing the document identifier and the secret key information; and sending the encrypted document to the client side. An electronic document after being downloaded by a user is the encrypted document, the encryption secret key is obtained through the fact that a user private key in certificated equipment needs to be used for decrypting the secret key information stored in a server, and then the encryption sec