Microsoft Point-to-Point Encryption (MPPE) encrypts data in PPP-based dial-up connections or PPTP VPN connections. Strong (128-bit key) and standard (40-bit key) MPPE encryption schemes are supported. MPPE provides data security between your PPTP connection and the tunnel server.
You can use the 40-bit version worldwide; it is built into every computer running Windows 2000. The 128-bit level of encryption is available only in the United States and Canada. You can enable the 128-bit version by installing a specific version of both client and server software.