Data encryption method and data transmission system

The invention discloses a data encryption method and a data transmission system. The data encryption method comprises the steps that a first dynamic password is generated according to transaction data; the first dynamic password and count data of a current transaction are computed to obtain a first key; sensitive data is encrypted with the first key to form first encrypted data; Mac of the sensitive data is computed with an equipment key to form first Mac data; and original data jointly formed by unencrypted data in the transaction data, the first encrypted data and the first Mac data is computed with the equipment key to generate a second summary, and the second summary is attached to the original data to be transmitted to a server together with the original data. Accordingly, the technical advantages that the data is protected by different keys, the transmitted data is prevented from being tampered, and the data transmission security and efficiency are effectively guaranteed are achieved. 本申请公开了种数据加密方法及数据传输