you would need a database for this.
create a table in the database as follows:
emailID - primary Key
emailAddress - test: This will store the email address
randomString - text: this will store a random string
emailEncrypted - text: This will store an encrypted copy of the email address
verified: int: default value 0: this will be used to verify the email address.
when they fill out the form, store the email address, a random string and the encrypted email address in the database. The default value for the verified column should be set to 0 so any new record created will automatically be set to not verified.
Security Assist has a random password generator that can be used for the random string and SHA1 encryption that can be used to encrypt the email address.
In the email, you will send a link to a verification page, send the random string and the encrypted email as part of this link in querystring variables:
verify.php?rand=<Random String>&em=<encrypted email address>
On the verify.php page, create a recordset that will be used to look up the corect record based on the "rand" and "em" variables to find the value in the emailID column, then use the update record behavior to update the verified column for that record.
