1. A decryption method comprising: receiving encrypted data, wherein the encrypted data is encrypted according to an RSA public key; and performing a plurality of operations in sequence, according to an RSA private key and the encrypted data, to acquire a decrypted data; wherein the operations comprise a plurality of decryption operations and at least one false operation, the decryption operations comprise at least one decryption multiplication operation and at least one decryption square operation, and the at least one false operation comprises at least one of at least one first false multiplication operation and at least one first false square operation; wherein at least one second false square operation is performed when the at least one decryption multiplication operation or the at least one first false multiplication operation is performed; wherein a binary form of the RSA private key comprises a plurality of bits, and a number of times that the at least one second false square operation is performed corresponds to a sum of a number or “1's” in the binary form of the RSA private key and a number of times that the at least one first false multiplication operation is performed.