@techreport{ietf-pppext-mschapv1-keys-00,
    number =    {draft-ietf-pppext-mschapv1-keys-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-pppext-mschapv1-keys/00/},
    author =    {Glen Zorn},
    title =     {{Deriving MPPE Keys From MS-CHAP V1 Credentials}},
    pagetotal = 7,
    year =      1998,
    month =     sep,
    day =       22,
    abstract =  {The Point-to-Point Protocol (PPP) {[}1{]} provides a standard method for transporting multi-protocol datagrams over point-to-point links. The PPP Compression Control Protocol {[}2{]} provides a method to negotiate and utilize compression protocols over PPP encapsulated links. The Microsoft Challenge-Handshake Authentication Protocol (MS-CHAP) {[}3{]} is a Microsoft-proprietary PPP authentication protocol, providing the functionality to which LAN-based users are accustomed while integrating the encryption and hashing algorithms used on Windows networks. Microsoft Point to Point Encryption (MPPE) {[}4{]} is a means of represent- ing PPP packets in an encrypted form. MPPE uses the RSA RC4 {[}5{]} algorithm to provide data confidentiality. The length of the session key to be used for initializing encryption tables can be negotiated. MPPE currently supports 40-bit and 128-bit session keys. MPPE session keys are changed frequently; the exact frequency depends upon the options negotiated, but may be every packet. MPPE is negotiated within option 18 {[}6{]} in the Compression Control Protocol. This document describes the method used to derive the initial MPPE ses- sion keys from MS-CHAP credentials. The algorithm used to change ses- sion keys during a session is described in {[}4{]}.},
}