Abstract: A verification method and a transaction verification method are provided. The verification method applicable for a secure device and an unsecure device utilizes the secure device to generate a match information for a user to see one-to-one substitution relations between a plurality of first verification data and a plurality of second verification data. When the user, after seeing the match information, selects the plurality of second verification data on the unsecure device, the unsecure device transmits a plurality of input data to the secure device, and the secure device converts the plurality of input data into a plurality of to-be-verified passwords according to the match information. The secure device then determines whether or not the plurality of to-be-verified passwords match with a plurality of pre-stored password data in the secure device.