include "keyring.m"; keyring := load Keyring Keyring->PATH; auth: fn(fd: ref Sys->FD, info: ref Authinfo, setid: int) : (string, array of byte); readauthinfo: fn(filename: string): ref Authinfo; writeauthinfo: fn(filename: string, info: ref Authinfo): int;
Auth returns a string and a byte array. If the byte array is nil then the authentication has failed and the string is an error message. If the byte array is non-nil, it represents a secret shared by the two communicating parties, and the string names the party at the other end of the connection.
If the authentication is successful and setid is non-zero then auth attempts to write the name of the party at the other end of the connection into /dev/user (see cons(3)); no error is generated if that does not succeed. If the authentication is not successful and setid is non-zero, auth writes the name nobody into /dev/user.
The authentication protocol is based on the Station-to-Station protocol. In the following, the parties are labelled 0 and 1. Sig0(x) is x signed with 0's private key.
0 -> 1 alpha**r0 mod p, CERTu0, PKu0 1 -> 0 alpha**r1 mod p, CERTu1, PKu1 0 -> 1 sig0(alpha**r0 mod p, alpha**r1 mod p) 1 -> 0 sig1(alpha**r0 mod p, alpha**r1 mod p)
At this point both 0 and 1 share the secret alpha**(r0*r1) which is returned in the byte array. Amongst other things, it can be the secret to digest or encrypt a conversation (see security-ssl(2)).
Readauthinfo reads a representation of an Authinfo from a file. It returns nil if there is a read error or a conversion error; it returns a reference to the Authinfo otherwise.
Writeauthinfo writes a representation of info to a file. It returns -1 if the write operation fails, 0 otherwise.
|KEYRING-AUTH(2 )||Rev: Thu Feb 15 14:43:27 GMT 2007|