A method of securely transferring data. The source data stored in a source memory (NV_MEM) is compared with the transferred data (COPY_ELT_X_V_MEM) that has been copied from the source memory (NV_MEM) into a “destination” memory (V_MEM). The method consists in reading from the source memory (NV_MEM) an integrity value (PI_ELT_X) associated with an element (ELEMENT_X_NV_MEM) such as file containing the source data, in calculating the integrity of a reconstituted element made up of the transferred data (COPY_ELT_X_V_MEM) associated, where appropriate, with the data of the source element (ELEMENT_X_NV_MEM) other than the data that was transferred, and in deciding that the transferred data (COPY_ELT_X_V_MEM) is identical to the source data when the integrity calculation gives a value identical to the integrity value of the source element (PI_ELT_X). The method applies to transferring data between components of a smart card.