Abstract: A method of protecting data applied in a computer device is provided. A designated file is encrypted by using a symmetric key to obtain an encrypted file. The symmetric key is encrypted by using a first public key of a first pair of keys and a first ciphertext is obtained. Information related to the designated file is obtained, and the related information of the designated file is uploaded to a blockchain. When decrypting the encrypted file, the related information of the designated file is downloaded from the blockchain to obtain the related information of the designated file. The symmetric key is obtained by decrypting a first ciphertext of the related information by using a first private key of the first pair of keys, and a decrypted file is obtained by decrypting the encrypted file by using the symmetric key.

Abstract: A file encryption and decryption method used in an electronic device generates a symmetric key and asymmetric keys, according to the number of sharers who are to receive the file. The asymmetric keys comprise public and private keys. An original file is encrypted by the symmetric key to generate a first encrypted file, encrypt the symmetric key with the public key to generate a first ciphertext, calculates an MD5 value of the original file, and calculates a first total length of the MD5 value, the public key, and the first ciphertext. The first total length is taken as a header file of the first encrypted file, the header file, the public key, and the first ciphertext are added to the first encrypted file to generate a second encrypted file, the procedure being repeated for each of the number of sharers.

Abstract: A method of protecting data applied in a computer device is provided. A designated file is encrypted by using a symmetric key to obtain an encrypted file. The symmetric key is encrypted by using a first public key of a first pair of keys and a first ciphertext is obtained. Information related to the designated file is obtained, and the related information of the designated file is uploaded to a blockchain. When decrypting the encrypted file, the related information of the designated file is downloaded from the blockchain to obtain the related information of the designated file. The symmetric key is obtained by decrypting a first ciphertext of the related information by using a first private key of the first pair of keys, and a decrypted file is obtained by decrypting the encrypted file by using the symmetric key.

Abstract: A method for processing data of transactions in a block chain system which applies a time control to a transfer of assets receives from a first user an asset transferring request, generating an asset transferring permission accordingly. If a current blockchain time meets a first time condition, assets recorded as the content of an asset transfer are allowed to be transferred from a first account address to a second account address. An asset transaction request from a second user can be received, and an asset transaction permission also generated accordingly. If current blockchain time meets a second time condition of the asset transaction permission, the second user and a third user, for asset forwarding or asset return purposes for example, may trade in relation to the permitted asset transaction content. A device for processing such data is also provided.

Abstract: An advertising operation method applied to an electronic device is provided. The method includes receiving a public key allocated by a server which acts as a seller. A request signal for obtaining a first website address of a product is sent to the server. The first website address of the product is received from the server. An encrypted electronic wallet address is obtained by encrypting a preset electronic wallet address using the public key. A second website address of the product is generated based on the first website address of the product and the encrypted electronic wallet address. The product is prompted to a client using the second website address of the product; and bonus is obtained from the server using the preset electronic wallet address.