What is verified by ZMAILs challenge-response authentication by email?
When you register for Zmail service, we send a confirmation message to you with your Zmail Usercode and use instructions. The confirmation message verifies that we are able to get mail through to you, and protects you in case someone forges a subscription request in your name. The confirmation message is also part of the challenge-response authentication loop, where ZMAIL authenticates you and your email address by a challenge-response test during your registration procedure. The test is satisfied when ZMAIL verifies positively whether an unpredictable code (your Usercode) sent in the confirmation message to your email address is timely read and used by you for login. This test confirms your registration request and verifies that you control both the password to that mailbox and the password to your ZMAIL account. A preliminary test may also be applied by ZMAIL, in some cases, when you are asked to first reply to a confirmation email sent to you; this email contains an unpredictable co
