BetweenUs features an online directory service where users can locate friends and associates. BetweenUs is a server and a client in one: the program doesn't need any external servers and every user can host a conference for up to 100 people. BetweenUs can be configured to work in three different encryption modes: public-key mode (uses 3072-bit Diffie-Hellman key-exchange protocol), symmetric mode (uses a secret passphrase), and PGP-compatible mode (uses an existing Pretty Good Privacy installation). All the messages and files are encrypted using the most reliable and proven ciphers that have resisted any form of cryptanalysis by the best mathematicians in the world:CAST (128-bit key), Triple DES (168-bit key), or Blowfish (448-bit key). Features: Full-strength unrestricted encryption; Familiar, easy-to-use, customizable interface and a comprehensive user manual; Public-key cryptography: you don't have to agree on a secret password; Seamless integration with PGP and ICQ.