Rated 5 out of 5 stars

Gmail S/MIME makes sending and receiving encrypted Gmail messages a breeze. The installation takes care of itself, and using the functionality is pretty easy to learn -- as soon as you figure out what you're being asked for in one dialog box that wants your "master password" (I assume this means the password for Firefox Password Manager, which I don't use, so I just enter blank here and it works).

The most difficult thing to understand (for me) was obtaining and installing the necessary certificate, but there are various resources telling you how to do that, such as the marknoble.com page referred to in a previous review, or the CAcert wiki pages.

When I did have a problem -- which turned out to be Mozilla's bug, not the add-on's -- the add-on developers responded quickly, informatively, and professionally; told me how to work around the problem; and gave me instructions for how to perform some further tests so they could make sure there wasn't a bug in their code that was associated with my problem. (There wasn't.)

As everybody says, signature verification would be very nice, but until the day when I'm using Gmail messages to wire millions of dollars around the world, I suppose I don't absolutely need it -- and I do appreciate the developers' continued work in that direction. (The sig verification, that is; I don't think they're working on making me an international financier, though that would be a nice add-on as well....)

This review is for a previous version of the add-on (0.4.6). 

Rated 3 out of 5 stars

Using 0.4.5 version of the addon with Firefox 3.5.7 under Ubuntu 9.10, USERTRUST network S/MIME certificate.
When trying to send and encrypted email it keeps asking the password...

This review is for a previous version of the add-on (0.4.5). 

Rated 3 out of 5 stars

This is great add-on for using encrypt and digital signature mail.
but for now it can't verify the certificate.

And this is the most problem for using double byte character like Japanese.
When I receive a encrypt mail, this add-on try to decode it. But it has big issue decoding double byte character. it is completely garbed.
then I can't read these.

I hope the author fix this issue. Please.

This review is for a previous version of the add-on (0.4.5). 

Rated 4 out of 5 stars

I am not able to download it, every time I go on download it now a page of firefox comes out even if I have already installed firefox...anybody could help me please?

This review is for a previous version of the add-on (0.4.5). 

Rated 5 out of 5 stars

Great addon!

Also the developers responded my BUG report enthusiastically and fix it very quickly.Nice!

This review is for a previous version of the add-on (0.4.4). 

Rated 5 out of 5 stars

Thawte no longer issues free email certificate... if you have one from them which is currently valid, you should have received an email from them stating such and giving you codes for a free 1-year certificate from Verisign

This review is for a previous version of the add-on (0.4.2). 

Rated 4 out of 5 stars

Great extension.

Why appear this messagem when I reply a message:

Unverified Message: This version of Gmail S/MIME does not support digital signature verification.
Signer: E=marciojacson@gmail.com

Tks

Marcio

This review is for a previous version of the add-on (0.4.2). 

Rated 4 out of 5 stars

Great extension.

Why appear this messagem when I reply a message:

Unverified Message: This version of Gmail S/MIME does not support digital signature verification.
Signer: E=marciojacson@gmail.com

Tks

Marcio

This review is for a previous version of the add-on (0.4.2). 

Rated 5 out of 5 stars

nice extension! agree with byyy that signature validation is probably the single most wanted missing feature.

Just had an email conversation with the developers -- they responded quickly and in great detail why it is so hard to add signature verification. The good news is: they are already working on it!

Hopefully it will be added soon. Thumbs up and keep up the good work!

-medo

This review is for a previous version of the add-on (0.4.1). 

Rated 5 out of 5 stars

Great extension, installed very easily and works as described. If only the signature verification would work it would be even better! Hope that Sean and Richard keep further developing and enhancing this great tool.

This review is for a previous version of the add-on (0.4.1). 

Rated 5 out of 5 stars

It works the way is is supposed to and very easy to configure. Seamless integration with Gmail.

This review is for a previous version of the add-on (0.4.0). 

Rated 3 out of 5 stars

In 'plain' GMail this works like a charm, in Google Apps EMail it doesn't work. Too bad, I hope this can be solved by the developers

This review is for a previous version of the add-on (0.4.0). 

Rated 3 out of 5 stars

Once installed, two additional buttons are added to gmail's interface. The icons themselves are clear, but the tooltip that appears is inverted and state what is currently selected, not what will happen if you click the toolbar button.

Clicking sign or encrypt (or indeed both) intercepts the "Send" button click and sends the email (now encrypted and/or signed) through gmail's SMTP interface. While this happens a message is displayed and the interface locks - if you're used to Gmail's snappy operation, this delay can seem long.

If you do not have a copy of the recipient's certificate, you are helpfully alerted that encryption is impossible. The addition of LDAP lookups would be welcome here, although obviously the extension has to crawl before it can walk.

Encrypted and signed reception is handled too. Decryption happens automatically, but signature validation (i.e. following the certificate's path up to the certification authority server such as Verisign or Thawte's root server) is invalid and, in theory, the certificate could be revoked without you knowing. The signature is parsed, however, so you can at least see the CN (Common Name) field of the signature.

S/MIME is rocket science for most users, so it's fantastic this plugin has been made. But while the addition of S/MIME functionality is great, actually being able to sign or encrypt your email requires you to get a X.509 certificate. Only Thawte provides a free, immediate option, and their UI and process is draconian and bordering impossible for the average user. Until the process of obtaining, installing and backing up your certificate is made easier, it doesn't really matter what improvements are made on this plugins.

Finally, while this extension is a good step towards S/MIME for the masses, it will always play catchup to Google's UI changes. It would be much more helpful if Google themselves offered an official Gears extension (thus working in IE, Firefox, Chrome etc.). This way, you would benefit from Google's security prowess and for the first time secure, non-repudiated email would be available for everyone.

This review is for a previous version of the add-on (0.4.0). 

Rated 5 out of 5 stars

I'm using and I am very happy with this plugin.

This review is for a previous version of the add-on (0.4.0). 

Rated 1 out of 5 stars

Sorry, I have to give it a 1. It did install. But it never worked.

This review is for a previous version of the add-on (0.4.0). 

Rated 3 out of 5 stars

Plugin is not be able to sign messages. Encryption works, but at the time of signing a window pops up to enter a password. After entering the (correct) password, and click on "OK" window pops up again. And so all the time. Unable to sign messages. Certificate from COMODO. Mail programs, such as OE or Thunderbird these certificates work.
Does anyone have similar symptoms? How can I fix this? Or perhaps am I doing something wrong.
Translated by google ;)

This review is for a previous version of the add-on (0.4.0). 

Rated 5 out of 5 stars

Great extension to increase your own personal security and privacy! Everyone should encrypt their email whenever possible. A great S/MIME beginner's tutorial is available for novices at http://marknoble.com/tutorial/smime/smime.aspx

This review is for a previous version of the add-on (0.3.10). 

Rated 5 out of 5 stars

For those getting the "You do not have a private key" error: you need to import your private key. Go to "View Certificates", click on the "Your Certificates" tab, and click "Import." Your private key is the file with the .p12 extension.

This review is for a previous version of the add-on (0.3.7). 

Rated 5 out of 5 stars

This is an excellent add-on. It allow my contacts to trust the emails that I send them. I had a few problems to begin (which was due to my lack of knowledge) however the authors were extremely helpful and guided me through getting it working.

This review is for a previous version of the add-on (0.3.7). 

Rated 3 out of 5 stars

I was happy version 0.3.7 of gmail s/mime fixed the problem I was having. With version 0.3.4 I would send an email from my home Mac OS X 10.4 Mail.app to my work gmail account, and the email would not decrypt. I got the error similar to:

Not Decrypted: You do not have a private key to decrypt this message.

But if I read the email with my work Mac OS X 10.4 mail.app the email would decrypt.

Now a few weeks later, I must have done something wrong to my firefox/gmail. I send an smime email from Mac os x 10.4 mail app to my gmail account with gmail smime add-on and firefox gives me: "Not Decrypted: You do not have a private key to decrypt this message."

I wonder what I did to break things. Hum.

This review is for a previous version of the add-on (0.3.7).