A method of controlling a mobile device comprising: detecting a handwriting input while the mobile device is in a lock state; verifying a user based on the handwriting input and searching for an instruction corresponding to the handwriting input, wherein verifying a user comprises: extracting an input feature of the handwriting input, wherein the input feature includes at least one of a shape of an inputting gesture and a speed of an inputting gesture; comparing the input feature with a pre-stored user verification information input feature; and determining whether the verification is successful based on the comparison result by: calculating a similarity between the input feature of the handwriting input and the pre-stored user verification information input feature based on the comparison result; and concluding that user verification is successful when the similarity is greater than or equal to a threshold value and accordingly releasing the lock state or concluding that user verification is unsuccessful when the similarity is less than the threshold value and accordingly maintaining the lock state; and wherein searching for an instruction comprises: extracting at least one recognizable character from the handwriting input; searching for an instruction corresponding to the at least one extracted character; and acquiring information regarding an operation corresponding to the instruction, wherein verifying a user and searching for an instruction is performed simultaneously according to a scheduling process of the mobile device, the method further comprising: performing the operation corresponding to the instruction when user verification is successful and an instruction corresponding to the handwriting input exists. detecting a handwriting input while the mobile device is in a lock state; verifying a user based on the handwriting input and searching for an instruction corresponding to the handwriting input, wherein verifying a user comprises: extracting an input feature of the handwriting input, wherein the input feature includes at least one of a shape of an inputting gesture and a speed of an inputting gesture; comparing the input feature with a pre-stored user verification information input feature; and determining whether the verification is successful based on the comparison result by: calculating a similarity between the input feature of the handwriting input and the pre-stored user verification information input feature based on the comparison result; and concluding that user verification is successful when the similarity is greater than or equal to a threshold value and accordingly releasing the lock state or concluding that user verification is unsuccessful when the similarity is less than the threshold value and accordingly maintaining the lock state; extracting an input feature of the handwriting input, wherein the input feature includes at least one of a shape of an inputting gesture and a speed of an inputting gesture; comparing the input feature with a pre-stored user verification information input feature; and determining whether the verification is successful based on the comparison result by: calculating a similarity between the input feature of the handwriting input and the pre-stored user verification information input feature based on the comparison result; and concluding that user verification is successful when the similarity is greater than or equal to a threshold value and accordingly releasing the lock state or concluding that user verification is unsuccessful when the similarity is less than the threshold value and accordingly maintaining the lock state; calculating a similarity between the input feature of the handwriting input and the pre-stored user verification information input feature based on the comparison result; and concluding that user verification is successful when the similarity is greater than or equal to a threshold value and accordingly releasing the lock state or concluding that user verification is unsuccessful when the similarity is less than the threshold value and accordingly maintaining the lock state; and wherein searching for an instruction comprises: extracting at least one recognizable character from the handwriting input; searching for an instruction corresponding to the at least one extracted character; and acquiring information regarding an operation corresponding to the instruction, wherein verifying a user and searching for an instruction is performed simultaneously according to a scheduling process of the mobile device, the method further comprising: performing the operation corresponding to the instruction when user verification is successful and an instruction corresponding to the handwriting input exists. extracting at least one recognizable character from the handwriting input; searching for an instruction corresponding to the at least one extracted character; and acquiring information regarding an operation corresponding to the instruction, wherein verifying a user and searching for an instruction is performed simultaneously according to a scheduling process of the mobile device, the method further comprising: performing the operation corresponding to the instruction when user verification is successful and an instruction corresponding to the handwriting input exists. performing the operation corresponding to the instruction when user verification is successful and an instruction corresponding to the handwriting input exists.