A data processing method, comprising: generating (S21) a decryption keystream of first data according to a physical start address of the first data before or during reading the first data from a flash, wherein the first data is a data block; and decrypting (S22) the first data through the decryption keystream and writing the decrypted first data into a cache; wherein the method further comprises: when the first data is initial first data, acquiring a logical start address of the initial first data from a microcontroller unit, MCU, and determining the physical start address of the initial first data according to the logical start address; and when the first data is non-initial first data, determining the physical start address of the non-initial first data according to the physical start address of the initial first data and an offset between the physical start address of the non-initial first data and the physical start address of the initial first data; wherein the method further comprises: determining that the first data is the initial first data when a first enable signal is received; and determining that the first data is the non-initial first data when a second enable signal is received, wherein the first enable signal is different from the second enable signal. generating (S21) a decryption keystream of first data according to a physical start address of the first data before or during reading the first data from a flash, wherein the first data is a data block; and decrypting (S22) the first data through the decryption keystream and writing the decrypted first data into a cache; wherein the method further comprises: when the first data is initial first data, acquiring a logical start address of the initial first data from a microcontroller unit, MCU, and determining the physical start address of the initial first data according to the logical start address; and when the first data is non-initial first data, determining the physical start address of the non-initial first data according to the physical start address of the initial first data and an offset between the physical start address of the non-initial first data and the physical start address of the initial first data; wherein the method further comprises: determining that the first data is the initial first data when a first enable signal is received; and determining that the first data is the non-initial first data when a second enable signal is received, wherein the first enable signal is different from the second enable signal. when the first data is initial first data, acquiring a logical start address of the initial first data from a microcontroller unit, MCU, and determining the physical start address of the initial first data according to the logical start address; and when the first data is non-initial first data, determining the physical start address of the non-initial first data according to the physical start address of the initial first data and an offset between the physical start address of the non-initial first data and the physical start address of the initial first data; wherein the method further comprises: determining that the first data is the initial first data when a first enable signal is received; and determining that the first data is the non-initial first data when a second enable signal is received, wherein the first enable signal is different from the second enable signal. determining that the first data is the initial first data when a first enable signal is received; and determining that the first data is the non-initial first data when a second enable signal is received, wherein the first enable signal is different from the second enable signal. <EOS>