How to set up Google Authenticator for a Gmail account.

Enable two-factor authentication. We do this not so much for the

two-factor, but because it allows creating an independent password that

is used only for IMAP and does not have access to the web interface of

Gmail. Click the email address in the upper right, then "Account". Click

"Security". By "2-step verification" click "Edit". Click through until

it lets you set up. The phone number you provided when the account was

created will be automatically filled in. Choose "Text message (SMS)"

then click "Send code". Get your text message, type it in, and hit

"Verify". Uncheck "Trust this computer" on the next screen. Finally

"Confirm". On the following summary page, click "Show backup codes" and

save the codes to encrypted storage. Future codes can be generated at

https://www.google.com/accounts/SmsAuthConfig.

Still on the 2-step summary page, click "Manage application-specific

passwords". Enter "IMAP" for the name and click "Generate password".

Now store this in reg-email.pass, as mentioned in the introduction.

Gmail. Two-factor authentication also enables you to set up a Google

Authenticator one-time password token and decouple the account from the

phone number. Click the email address in the upper right, then

"Account". Click "Security". By "2-step verification" click "Setup".

Click through until it lets you set up. The phone number you provided

when the account was created will be automatically filled in. Choose

"Text message (SMS)" then click "Send code". Get your text message, type

it in, and hit "Verify". Uncheck "Trust this computer" on the next

screen. Finally "Confirm".

Now set up a Google Authenticator secret and. Under "Primary way you

receive codes", click "Switch to app". Choose "BlackBerry" and

"Continue". Copy the secret key to a file. Use a program such as

https://github.com/tadeck/onetimepass to generate a verification code

and click "Verify and Save". Now you can remove the phone number if you

wish by clicking "Remove" next to it.

Under "Backup codes", click "Print or download", and save the codes to a

file so you can log in if all else fails.

Still on the 2-step verification page, click the "App-specific

passwords" tab and the "Manage application-specific passwords" button.

Under "Select app", select "Custom" and enter "IMAP" for the name. Click

"Generate". Store the password in reg-email.pass, as mentioned in the

introduction.