Share (P2P)
"Share" uses encryption to hide the identity of who is transferring or what they are transferring. It is non-centralized so it cannot be easily shut down and it supports multiple source "swarm" downloading. All files are transferred encrypted so they must be decrypted upon download completion. In the meantime they are stored in encrypted form in a "Cache" folder. This folder is also used to allow recently downloaded files to be shared among the network based on priorities.
Mcrypt
mcrypt is a replacement for the popular Unix crypt command.
crypt was a file encryption tool that used an algorithm very close to the
World War II Enigma cipher. Mcrypt provides the same functionality but uses several modern algorithms such as AES. Libmcrypt, Mcrypt's companion, is a library of code which contains the actual encryption functions and provides an easy method for use. The last update to libmcrypt was in 2007, despite years of unmerged patches. These facts have led security experts to declare mcrypt abandonware and discourage its use in new development. Prefer ccrypt, libressl, and others.