Libreswan Opportunistic IPsec using LetsEncrypt

Introduction

Libreswan Opportunistic IPsec using LetsEncrypt is a project created during Google Summer of Code 2019. It adds a utility `letsencrypt` to the `ipsec`. letsencrypt invokes any of several utilities involved in controlling the Opportunistic Encryption system, running the specified {command} with the specified [argument] as if it had been invoked directly. e.g. `ipsec letsencrypt -h` lists the available commands.

It is a program in libreswan, which integrates libreswan with Opportunistic Encryption utilities. The script provides various OE functionality e.g. initial OE setup, testing configuration/connection, generating and updating Let's Encrypt certificates. The details about the utilities and using them can be found in the Documentation: Libreswan Opportunistic IPsec using LetsEncrypt . Also, the documentation includes the sample output for each {command} and [argument].

Implementation

Various functionalities of the project are listed below:

• Can establish the secure OE (Opportunistic Encryption) connections between two hosts (client and server).
• Checks for the success in establishing the OE connection.
• Easy to install on the hosts (client and server).
• Can test OE connections between two hosts.
• Checks if certbot is installed (on the server).
• Can generate Let's Encrypt certificates for the server using certbot.
• Generates the certbot configuration for reusing the private key.
• Enables automatic update of the generated certificates, keeping the private key same.
• Generates the #pkcs12 file.
• Imports the generated certificates into NSS Database to be used for OE.
• Downloads the LetsEncrypt CA and intermediate certificates.
• Saves the default client/server configuration.
• Displays OE connection status to the user.
• Displays the certificates installed in NSS database.
• Provides details about various available utilities, {commands} and [arguments].