A method for sending data, comprising: achieving a data exchange agreement for exchanging data between a first user and a second user, wherein the achieving of the data exchange agreement comprises i) receiving and publishing, by a data exchange platform, data information issued by a first terminal associated with the first user, ii) receiving, at the data exchange platform, an order placing request for the published data information by a second terminal associated with the second user, iii) sending the order placing request to the first terminal, and iv) receiving, by the data exchange platform, confirmation information sent by the first terminal for the order placing request to achieve the data exchange agreement between the first user and the second user that is to be stored in a block chain, wherein the data exchange agreement is associated with exchanging first data from the first user and second data from the second user, wherein the data exchange agreement includes (a) identity information of the first user and the second user part of the data exchange, (b) feature information of the exchanged data, (c) data use specifications, and (d) measures in case of a breach of the data exchange agreement for the first user and the second user; receiving, by the data exchange platform, a first key sent by the first terminal of the first user after the first terminal uses the first key to encrypt first data and a second key sent by the second terminal of the second user after the second terminal uses the second key to encrypt second data; sending, by the data exchange platform, the first key to the second terminal, such that the second terminal, after receiving encrypted first data directly sent from the first terminal, decrypts the received encrypted first data based on the first key to obtain the first data; and after sending the first key to the second terminal and receiving confirmation information sent by the second terminal for the first data, sending, by the data exchange platform, the second key to the first terminal for decrypting encrypted second data that is received from the second terminal, wherein the confirmation information defines that the first data conforms to the data exchange agreement. achieving a data exchange agreement for exchanging data between a first user and a second user, wherein the achieving of the data exchange agreement comprises i) receiving and publishing, by a data exchange platform, data information issued by a first terminal associated with the first user, ii) receiving, at the data exchange platform, an order placing request for the published data information by a second terminal associated with the second user, iii) sending the order placing request to the first terminal, and iv) receiving, by the data exchange platform, confirmation information sent by the first terminal for the order placing request to achieve the data exchange agreement between the first user and the second user that is to be stored in a block chain, wherein the data exchange agreement is associated with exchanging first data from the first user and second data from the second user, wherein the data exchange agreement includes (a) identity information of the first user and the second user part of the data exchange, (b) feature information of the exchanged data, (c) data use specifications, and (d) measures in case of a breach of the data exchange agreement for the first user and the second user; i) receiving and publishing, by a data exchange platform, data information issued by a first terminal associated with the first user, ii) receiving, at the data exchange platform, an order placing request for the published data information by a second terminal associated with the second user, iii) sending the order placing request to the first terminal, and iv) receiving, by the data exchange platform, confirmation information sent by the first terminal for the order placing request to achieve the data exchange agreement between the first user and the second user that is to be stored in a block chain, wherein the data exchange agreement is associated with exchanging first data from the first user and second data from the second user, wherein the data exchange agreement includes (a) identity information of the first user and the second user part of the data exchange, (b) feature information of the exchanged data, (c) data use specifications, and (d) measures in case of a breach of the data exchange agreement for the first user and the second user; receiving, by the data exchange platform, a first key sent by the first terminal of the first user after the first terminal uses the first key to encrypt first data and a second key sent by the second terminal of the second user after the second terminal uses the second key to encrypt second data; sending, by the data exchange platform, the first key to the second terminal, such that the second terminal, after receiving encrypted first data directly sent from the first terminal, decrypts the received encrypted first data based on the first key to obtain the first data; and after sending the first key to the second terminal and receiving confirmation information sent by the second terminal for the first data, sending, by the data exchange platform, the second key to the first terminal for decrypting encrypted second data that is received from the second terminal, wherein the confirmation information defines that the first data conforms to the data exchange agreement.