PRoot is a user-space implementation of "chroot", "mount --bind", and "binfmt_misc". This means that users don't need any privileges or setup to do things like using an arbitrary directory as the new root filesystem, making files accessible somewhere else in the filesystem hierarchy, or executing programs built for another CPU architecture transparently through QEMU user mode. Also, developers can add their own features or use PRoot as a Linux process instrumentation engine thanks to its extension mechanism. Technically, PRoot relies on "ptrace", an unprivileged system call available in every Linux kernel.
Paranoid TelnetD is written in straight C with few dependencies. It is intended for use with embedded or legacy devices (like the hand-scanners used in warehouses) that communicate via telnet. It features: 'telnet only' user accounts, separate from the system authentication (so only the specified usernames/passwords can login via telnet, and only via telnet); user, IP address, and MAC address whitelisting/blacklisting; chrooting with 'bind mounts' to allow access to certain directories under the chroot jail; and 'honeypot mode' in which all authentication fails and all events are logged at syslog 'crit' level.