FreeBSD provides robust support for encryption both for data at rest and in transit, implementing a variety of mechanisms to ensure data security.

Encryption for Data at Rest

GEOM-based Encryption:

FreeBSD uses the GEOM framework to support disk encryption. Specifically, the `geom_eli` module provides support for Full Disk Encryption (FDE). With `geom_eli`, you can encrypt entire disk partitions or volumes. This module uses the `crypt(4)` framework and supports various encryption algorithms, including AES.

 Setup: To use GEOM ELI, you typically set up a provider using `geli init` and then attach it with `geli attach`. The encrypted volume is accessed through the GEOM framework, and the data is decrypted on-the-fly.

 Key Management: Encryption keys can be managed using passphrases or stored in files. For secure key management, FreeBSD supports key management schemes like HMAC-based key derivation.

ZFS Encryption:

FreeBSD also supports encryption with the ZFS file system, which has native support for dataset-level encryption.

Encryption Options: ZFS supports several encryption algorithms, including AES-256 in both CBC and XTS modes. It allows you to encrypt ZFS datasets, providing flexibility in encrypting specific parts of your file system.

 Key Management: ZFS handles key management, including key encryption and the ability to use different keys for different datasets. It integrates with FreeBSD's `zfs` command suite to manage encryption settings.

Encryption for Data in Transit

IPsec:

FreeBSD provides support for IPsec, which is used to secure network traffic through encryption. IPsec can operate in both transport mode (encrypting only the payload) and tunnel mode (encrypting the entire packet).

Configuration: You configure IPsec in FreeBSD using the `racoon` daemon or `ipsec` utility, and you can define policies and security associations through configuration files.

TLS/SSL:

For applications that require encryption of data in transit, FreeBSD supports TLS (Transport Layer Security) and SSL (Secure Sockets Layer) through various libraries and tools.

Libraries: FreeBSD provides support for popular TLS libraries like OpenSSL and LibreSSL. These libraries enable encryption for web servers (e.g., Apache, Nginx), email servers, and other network services.

Applications: Many applications on FreeBSD, including web servers, mail servers, and VPN clients, leverage these libraries to provide encrypted communications.

VPN Support:

FreeBSD supports various VPN protocols, which use encryption to secure data in transit:

OpenVPN: A popular VPN solution that uses SSL/TLS for secure communication.
WireGuard: A modern, high-performance VPN protocol supported natively in FreeBSD for securing communications.

SSH:

Secure Shell (SSH) is a common protocol for encrypted remote access. FreeBSD includes the OpenSSH suite, which provides secure command-line access, file transfers (using SCP/SFTP), and tunneling features.

Summary

FreeBSD integrates encryption into both data at rest and data in transit through a variety of built-in tools and frameworks. For data at rest, it offers GEOM-based encryption and ZFS dataset encryption. For data in transit, it provides support for IPsec, TLS/SSL, VPNs, and SSH, ensuring that communications are encrypted and secure.