Mailvelope

Click here to open Mailvelope in the Chrome app store. Then click Install. When the confirmation prompt appears, click Install.

After installation, a lock icon is displayed in the main Google Chrome toolbar (to the right of the address bar). Click it to open the Mailvelope main menu.

Browser action popup

Firefox

Click on the icon below to download Mailvelope from download.mailvelope.com. Choose Allow and Install in the Firefox dialogs to install Mailvelope as an add-on in your browser.

Basics

Public and Private Keys

OpenPGP and therefore Mailvelope use public-key encryption, which means a key is split into two parts: public and private keys with different purposes:

• Public key – Used to encrypt a message. Is and should be available to everybody.
• Private key – Used to decrypt a message. Needs to be stored securely. Access is restricted by password.

This concept is illustrated on the page "How Gpg4win works". Gpg4win is another application based on OpenPGP, and the same principles also apply to Mailvelope.

Exchanging Keys

In order to send an encrypted email, you must have the public key of the recipient. Therefore, before secure communication can happen between two people, they must exchange their public key. There are multiple ways a public key can be distributed:

• Sending it by email to the recipient. See the Exporting Keys section to find out how this works in Mailvelope
• Publishing the key on a website for everyone to access.
• Uploading the key to a keyserver.

Message Formats

With OpenPGP, public and private keys, as well as encrypted messages are encoded in a specific text format that allows them to be exchanged or stored as text files.

For example, a public key would look like this:

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: Mailvelope v1.1.0
Comment: https://www.mailvelope.com

xo0EUI5G5QEEAI7NxVI17OibiyMTAYcLEdForPt/46+4RrUk/DMRNetAV4Ve
UJaFPRLuWcZjq8BFV01nzGQd3NG8CDO8qI37fVUXVGe03mP8f8DB2GP/cmu3
mOzlEpTa4WsaKTgdx8E00qJZ6v66NQVRbm/7JG8Psj/didl2cQHeGCGCYsx9
OrfLABEBAAHNF0pvaG4gRG9lIDxqb2huQGRvZS5vcmc+wpwEEAECABAFAlCO
RuYJEBLyB87MrGtYAADcQgP/dVVIIldGaeozWFAcM94+uMfdbY9tpOK/0kHE
MDL5WqlHj865VloAdtk+rlDZ0NnW2gc92zMGW+a13zYHkvN8oE6UtUsG4uaQ
GqSbqWF5pUQ+KK/fJ49NaH2p+nahdI9IpvmKowXaARKVY8QqBLzaXjGg3/VL
BI86am8qJEULisI=
=5VIW
-----END PGP PUBLIC KEY BLOCK-----

Key Handling

Click on Mailvelope's lock icon  in the toolbar to open the main menu. Click Options to navigate to Key Management, where all the keys are stored:

Key Ring view

Generating Keys

To use Mailvelope, at least one key pair (consisting of a public and private key) must be available. You can either generate a new key pair as explained in this section, or import an existing key pair as described below.

Click Generate Key to open the key generation dialog. Fill out the boxes and assign a key password. Make sure you never lose this password. If it is lost, the password cannot be recovered and the key can no longer be used.

Key generation dialog

Enter all the necessary information. Click Submit to start generating a key. Afterwards, you can see the result in the key list by selecting Display Keys.

Importing Keys

Existing keys can be imported from other applications. In the option menu, click Key Management and then Import Key.

Key import dialog

Import key from file

With this feature, you can select a key file on your storage device which will be imported into Mailvelope.

Import key as text

Paste any keys into the text box in text format as shown above in the Message Formats section. Clicking on Importwill extract all keys from the text and transfer them into the local keyring.

Key search

Search for PGP keys on public key servers by entering email address or name of key owner.

Key search by name or email address

Search results will be displayed on the key server website in a new tab.

Search results

After clicking on the displayed keyID, the key text will be shown and Mailvelope will be able to detect the key.

Display of key text

With another click on the key symbol the key is imported into Mailvelope.

Exporting Keys

Key export functionality is used to export keys in text format. We can use this function to publish public keys or to make a backup of a public-private key pair in a secure place.

Exporting all keys

For this purpose, click the Export button on the "Display Keys" option page. The keys are saved in asc format. This format can be read by all common PGP implementations.

Exporting individual keys

Hover over the relevant key pair and click the information icon (i). Switch to the Export tab and select the key(s). Then click Download.

Defining the primary Key

In the Display Keys menu, you can view more information about each key using the information icon (i). You can define your key as the primary key here. The primary key is always used unless another key is explicitly selected.

Messages

Mailvelope extends the user interface of webmail sevices with controls that can be used for encryption and decryption of emails.

Depending on the webmail provider, Mailvelope offers two levels of integration:

• Webmail providers like GMX, Posteo or WEB.DE offer a deep integration with Mailvelope. Components of Mailvelope are directly integrated into the user interface of the webmail service. Thus, end-to-end encrypted emailing is an easy and user-friendly task, as Mailvelope ensures that all private data is isolated from the webmail provider and any third party.
• For all other webmail providers (e.g. Gmail™, Outlook.com™, Yahoo!™ etc.) Mailvelope offers a lighter integration, its components seamlessly extending the user interface with PGP functionality.

The following describes the lighter integration of the Mailvelope components for message encryption and decryption.

Encrypting Messages

Email messages are created and encrypted in an external editor.

The Compose button  is displayed in all email composing areas of the webmail provider and will launch Mailvelope's external editor.

Compose button

Clicking on the Compose button will open a new popup with a separate editor. This ensures that the email creation and encryption process is completely isolated from the webmail provider.

Compose popup

The email can now be composed. You can choose the recipients, or more specifically the people who should be allowed to decrypt the message, by adding the email address to the upper input field in the dialog. Like in other email clients you can also search in this field for recipients by name. For each recipient, there has to be a public key available in Mailvelope's keyring. If you enter an unknown email address, Mailvelope will automatically search on the Mailvelope key server (keys.mailvelope.com) for PGP keys and import found keys without further action required. Alternatively you can also import keys manually as described in Importing keys.

Next, click the Encrypt button to encrypt the message and transfer the result back to the webmail client.

Encryption dialog

By default, the option Always add my primary key to the list of recipients is active and allows that you can decrypt and read the messages in your Sent folder. In the Mailvelope settings see Options -> General to change this setting.

For the mail providers Gmail™, Outlook.com™ and Yahoo!™, Mailvelope will automatically transfer the recipients back and forth between the mail client and the Mailvelope editor. That means you can enter the recipient email address in e.g. Gmail and once the Mailvelope editor opens the recipient is pre-selected. Or the other way round, a recipient you enter in the Mailvelope editor will automatically transferred to the Gmail compose email dialog.

With the Options button in the Mailvelope editor you can access the option to sign the message.

Message signing option

After clicking Encrypt with the sign option active the message will be first signed with the selected private key and then encrypted. The link Sign all messages with primary key will open the Mailvelope settings page where you can choose to always sign messages with the primary key.

You can also Sign only the email if the signing option is active. A PGP signature is created and directly inserted into the email text. Be aware that this action transfers the unencrypted content of the email to the webmail provider.

Encrypted message copied to webmail provider

Now the encrypted message can be sent as usual.

Warning: do not use the webmail provider's main window while the external editor is open. To transfer the encrypted message successfully, it is important that you do not navigate away from the compose view of your webmail provider.

The Back button  resets the content of the webmail editor to its initial state. Warning: This deletes your encrypted message.

Message Decryption

Whenever Mailvelope detects an encrypted message in your webmail client, it marks it with a closed envelope icon. Click on it to decrypt the message.

Marked encrypted message

Next, enter your key password and click OK.

Password dialog

Mailvelope tries to find the private key that is required to decrypt the message. If the correct key is found in the keyring, the corresponding User and Key ID are displayed in the password dialog.

If Mailvelope does not have the correct private key to decrypt the message in its keyring, the following error message is displayed: No private key found for this message. Required private key IDs: ....

After the key is unlocked with the password, the message is decrypted and directly shown in the marked area.

Decrypted email

Verify signed messages

If an encrypted message contains a signature, Mailvelope will verify the signature and show the result with a label in the upper right corner of the decrypted message. A click on the Signed digitally label will open up a dialog showing the verification result and signature details.

Signature verification

Signature verification is currently only enabled for the following email providers: Gmail™, Outlook.com™ and Yahoo!™.

File Encryption

Click on Mailvelope's lock icon  in the toolbar to open the main menu. Click Options and choose File Encryptionfrom the top menu bar.

With the file encryption feature of Mailvelope, you can encrypt files on your storage devices according to the PGP standard. As with email encryption, the files will be encrypted with the recipient's public key.

The file encryption feature can also be used to encrypt and decrypt email attachments.

Background: email providers that directly integrate Mailvelope into their email application will support encrypted email attachments automatically. For email providers like Gmail™, Yahoo!™ or Outlook.com™ there are restrictions in the Mailvelope editor and encrypted attachments are not directly supported. The file encryption outlined here offers an alternative in this case, as it is possible to encrypt email attachments manually instead.

As of now Mailvelope supports only the ASCII Format of the PGP encryption with the file extension .asc.

Encrypt files

In a first step files on the storage devices will be selected for encryption with + Add.

File selection for encryption

Click on Next and choose the recipients you want to encrypt the files for.

Choose recipients

After clicking Encrypt the files are encrypted for the selected recipients.

Display encrypted files

Select the encrypted .asc files to save them to your downloads folder or choose Save all.

Decrypt files

The steps to decrypt files are similar to the encryption process. First, choose Decryption in the left menu. Then, use the + Add button to select on the storage device the .asc files to be decrypted files. The decrypted files will be displayed once you entered your private key password.

File selection for decryption

Watch List

Mailvelope comes preconfigured to work with the following webmail services:

• De-Mail™
• Gmail™
• GMX™
• Outlook.com™
• Posteo™
• WEB.DE™
• Yahoo!Mail™

Using this general approach, it can be configured to work with any webmail provider. You can set these settings in the List of Email Providers section of the Options page.

The watch list defines a set of websites that are enhanced with the functionality provided by Mailvelope.

Deactivating Mailvelope for a site

By default, Mailvelope is active for all sites on the watch list. To deactivate a site, click Edit in the corresponding row and change the Active value. Confirm with OK.

Adding a website to the watch list

Load the website you want to add to the watch list in a browser tab (the active tab). Click the lock icon  in the browser extension toolbar to open the main menu. Click + Add. The browser will open a new tab with Mailvelope's Options page and will add the website to the watch list. Reload the website to activate Mailvelope.

When you select + Add, Mailvelope analyzes the website's frame structure and adds this information to the watch list. Because the internal structure of the website might change in different scenarios, the following procedure is recommended when adding new websites:

1. Open your webmail provider's website and log in.
2. Navigate to your inbox and open an email.
3. Select + Add in Mailvelope's main menu.
4. A new tab opens and a new entry is added to the watch list.
5. Switch back to the webmail site and compose a new email.
6. Click on the lock icon again and select + Add.
7. Reload the page with F5.

Click one of the entries to set additional settings:

Active: You can disable the entry here without deleting it.

Site: The name of the entry in the watch list.

Status/Domain pattern/API: Allow individual pages to or prohibit individual pages from using the Mailvelope API.

Advanced: When expanding a row in the watch list, we see the frames that will be scanned for encrypted emails and email composing areas. If we can identify irrelevant frames (e.g. from ads), we can disable the entry and minimize the scanning effort.

You can also manually add websites and their frame structures to the list. However, this process is not described here.

Security

Mailvelope offers end-to-end encryption, which means that the application must ensure that the user's confidential data can never leave the computer.

Mailvelope's user interface consists of a set of isolated elements floating on top of the webmail provider's UI elements. This tight integration improves usability, but also requires measures to prevent any data leakage.

Mailvelope's security goals are as follows. All data must be safe even if:

• A rogue sender is part of the communication
• The webmail provider has malicious intent
• The webmail provider was attacked or the user has a malicious tab opened
• This attack scenario was thoroughly tested in a penetration test by Cure53, who was also involved in developing the security concepts used by Mailvelope.

In this section, we look at security from an end user perspective. Further information is also available in the security section of the FAQ. The relevant settings can be found in the following dialog.

Security Settings

Click the Mailvelope icon , then Options from the menu, then the Options tab and Security to open the security settings.

Security settings

Remember passwords for this browser session

Mailvelope can save private keys' passwords in the local memory. You can enable this option in the security settings or with the password dialog. Passwords have a set lifetime, which can be adjusted in the settings, and are always deleted when you close the browser window.

Security background

Mailvelope input fields are identified with a background of lock icons. In order to detect potential fakes more easily, you can set how the background should look here, as well as adjusting the angle, scaling and color of the icons.

Where are decrypted messages displayed?

Two different modes are available for displaying the encrypted messages:

On the email provider's page

This offers the best usability. The encrypted messages are displayed inside an isolated window (sandbox) that is not accessible by the webmail provider.

The security background also appears with the decrypted message so that you can clearly determine that the displayed message is the one decrypted by Mailvelope.

In a separate popup from Mailvelope

The decrypted message will be shown in a new browser window.

This setting is only relevant for email providers without integration of the Mailvelope API. In the integrated version as implemented by GMX/WEB.DE/De-Mail decrypted messages are always displayed in the user interface, but in an isolated area which is not accessible by the mail provider.

Security log

Click the lock icon  in the Last activities section to view the security log. All events related to Mailvelope are logged here. If necessary, check the log for suspicious activities. Click More to go to a more detailed view