Lotus Notes emailing service facilitates users with multiple benefits and features. It is considered as the most secure application due to implementation of facilities like; ACL and encryption. Lotus Notes allows to protect the emails using encryption method and users can apply the encryption on the emails to avoid any unauthorized access. This encryption is only applied to the body of email and the header information like; Subject, To, From, etc. fields are not encrypted. Lotus Notes users can encrypt the emails to be sent to other Lotus Notes users and S/MIME supporting applications. The mail encryption can be done to emails to be received as well from Lotus Notes users. It uses recipient’s public key, which is stored in sender’s contacts or in directory for encrypting outgoing/saved emails. Mails to be sent to foreign domain cannot be encrypted. Let us learn the complete procedure how to encrypt email in Lotus Notes.

Step-wise Method to Encrypt Emails in Lotus Notes

  1. Launch the Lotus Notes application, here Notes version 9.0 has been used.
  2. Go to File Menu, and explore the options available in it.
  3. Select Security and then click on User Security under this option

·         As you select User Security, a window will pop up where you can select the encryption options. You will get four options as;

  •  Encrypt mail that you send
  • Sign mail that you send
  • Encrypt saved copy of mail that you send
  • When receiving unencrypted mail, encrypt before storing in your mail file.


·         Choose “Encrypt mail that you send option” Click OK and exit the window.

This method will help you to encrypt all the messages in Notes application, which will be sent to other users. In this way, the email messages are protected and its unauthorized access can be ceased.

Method to Encrypt Incoming Mail for a Mail File

Encryption to the incoming email messages can be done by Notes users. Through this type of encryption, all the incoming emails, which are going to be stored in the mailbox will be encrypted and protected. This type of encryption is only possible on user’s side, if the user is having Editor Access and privileges to person documents in the IBM® Lotus® Domino® Directory. Users with Editor’s privileges can do the below mentioned settings for the encryption.

  • Open user’s Person document available in Lotus Domino Directory.
  •  Click on the Edit Person option and then click Basics.
  • Here, in the option available “When receiving unencrypted mail, encrypt before storing in your mail file”, select Yes.
  • Save the document

How the Applied Encryption Works

The sender sends a message selecting the encryption option like it is done in the above-mentioned steps. A random encryption key is generated by Lotus Notes application and the message is encrypted with the same key. This random encryption key is generated with recipient’s public key and a new key for the message is created. The recipient’s public key is stored in Lotus Domino Directory or LDAP directory. If the encrypted messages are addressed to many recipients, message will be encrypted with random key generated using public key of each recipient. On the recipient’s side when recipient opens the encrypted email message, the mail application of recipient tries to decrypt this key applied for encryption using recipient’s private key. Once successful, the message is decrypted and recipient can read the message easily. In case the decryption of the message fails at the recipient’s side, a message is displayed showing failure of decryption.