Abstract: Electronic apparatus and method for decryption, electronic apparatus and method for inputting password encryption, and system comprising said apparatuses are provided. The electronic apparatus comprises a detection unit, a generation unit, and a decryption unit. The detection unit is configured to detect a biological feature. The generation unit is configured to generate a key and a copied key according to the biological feature. The decryption unit is configured to decrypt an encrypted text by a decryption algorithm according to the key to get an input password. The input password is used to decide whether the electronic apparatus can be operated or not. The apparatus for inputting password encryption encrypts the input password by the copied key. The methods are executed to achieve functions of the aforementioned apparatuses.