How to decrypt SHA1 passwords

Hi all,

I have an asp.net page where I have used FormsAuthentication.HashPasswordForStoringInConfigFile. Encrypted password is saved in database. I have created a forgotPassword page. Where I need to send user his password. How can I decrypt it and send it to user. if SHA1 can not be decryoted what other option should I use to encrypt the passwords?

Regards,
Asif Hameed 
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