Digitally signed emails. What is it and how do digital signatures work?

Digital signatures and end-to-end email encryption

End-to-end encryption protect your message privacy, while digital signatures provide additional security attributes:

  • Sender verification: the sender is who he/she claims to be
  • Integrity: The message was not altered during transit
  • Non-repudiation: the sender cannot deny having sent the message

A digital signature is similar to a handwritten signature.  However it offers far more security.

How do Digital signatures work?

A digital signature only requires the sender (the signer) to have cryptographic keys (a private key and a public key). The sender signs the message locally on his/her device (using sender’s private key). Furthermore, the receiver verifies it on his device by using sender’s public key. The process works as follows:

  1. Alice (sender) generates a key pair and shares her public key with Bob (a one-time pre-requisite).
  2. Alice signs the message using her private key in her device and sends the message to Bob.
  3. Bob receives the signed message on his device and verifies the signature using Alice’s public key.

Digital signatures are commonly referred to as ‘Electronic signatures’. They are widely used in both personal and professional contexts.

How to send digitally signed emails using Mailfence

First generate your key pair, and share your public key.  Digitally signing emails with Mailfence is as simple as being illustrated in the image below.

digital signatures
Sending and receiving signed emails using Mailfence.

Yes, Mailfence – secure and private email service has made it super easy!

Furthermore, you can check our user guide for more details on how to sign OR sign & encrypt your messages. In addition, you can check and perform other key management operations.

Even easier with our ‘Integrated key store’

end to end encryption and key management
A preview of our integrated key store to perform key management – Mailfence

With an integrated key store, users can generate, export, or import a key pair.  For instance, they can also manage their key or add recipient’s public keys.  All of this without any external plugin or add-on.

This gives users control over their privacy.  In addition, we offer complete reversibility.  In this case, a user can export his/her key pair as well as all the other data stored in his/her account such as calendar, contacts, and documents.

Digitally signing  without end-to-end encryption

In a recent post, we explained that digital signatures combined with end-to-end encryption increase security. For instance, it can also be useful to sign emails digitally without encrypting them:

  • Digitally signing emails with attachments reassures the receiver of the email. In addition, this assures that both the content and the attachment have not been tampered with during transit. This increases the legal value of the email.

Consent with legal & regulatory requirements in various environments (for e.g., sales contracts, vendor & supplier agreements, …)

Wanna learn more about OpenPGP digital signature best practices?

At Mailfence, we have designed an easy to use end-to-end encrypted email.  We believe that users have an absolute and irrevocable right to internet privacy.  In case you want to leave either Yahoo Mail or Gmail.

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– Mailfence Team

Avatar for M Salman Nadeem

M Salman Nadeem

Salman works as an Information security analyst for Mailfence. His areas of interests include cryptography, security architecture and design, access control and operations security. You can follow him on LinkedIn @mohammadsalmannadeem

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