1 .TH PASSWD 1
2 .SH NAME
3 passwd, netkey \- change user password
4 .SH SYNOPSIS
5 .B passwd
6 [
7 .I username\fR[@\fPdomain\fR]\fP
8 ]
9 .PP
10 .B netkey
11 .SH DESCRIPTION
12 .I Passwd
13 changes the invoker's Plan 9 password and/or APOP secret.
14 The Plan 9 password is used to login to a terminal while
15 the APOP secret is used for a number of external services:
16 POP3, IMAP, and VPN access.  The optional argument specifies
17 the user name and authentication domain to use if different
18 than the one associated with the machine
19 .I passwd
20 is run on.
21 .PP
22 The program first prompts for the old Plan 9 password in the specified
23 domain to establish
24 identity.
25 It then prompts for changes to the password and the
26 secret.
27 New passwords and secrets must be typed twice, to forestall mistakes.
28 New passwords must be sufficiently hard to guess.
29 They may be of any length greater than seven characters.
30 .PP
31 .I Netkey
32 prompts for a password to encrypt network challenges.
33 It is a substitute for a SecureNet box.
34 .SH SOURCE
35 .B \*9/src/cmd/netkey.c
36 .br
37 .B \*9/src/cmd/auth/passwd.c
38 .SH "SEE ALSO"
39 .MR encrypt (3)
40 .PP
41 Robert Morris and Ken Thompson,
42 ``UNIX Password Security,''
43 .I AT&T Bell Laboratories Technical Journal
44 Vol 63 (1984), pp. 1649-1672