i have hashed password using SHA1 and for login i am using same algo, so when user enters password, both hased gets matched and he/she logs in, thats ok and working , quite happy :)

but problem is that sha1 cannot reversed , its a one way algo,

and i want to provide facility of RESET password in my website , so how can i get around this problem ? is there any way to provide reset password while using sha1, any alternative, to provide thsi facility while using sha1 . Sha1 is customers requirement and i have to use it ! so help please !