xref: /netbsd-src/usr.bin/pwhash/pwhash.1 (revision 35f948d4a1b32765e2469cfb66c55f2edbaf2c94)

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.Dd October 20, 2021
.Dt PWHASH 1
.Os
.Sh NAME
.Nm pwhash
.Nd hashes passwords from the command line or standard input
.Sh SYNOPSIS
.Nm pwhash
.Op Fl km
.Op Fl A Ar variant[,params]
.Op Fl b Ar rounds
.Op Fl S Ar rounds
.Op Fl s Ar salt
.Op Fl p | Ar string
.Sh DESCRIPTION
.Nm
prints the encrypted form of
.Ar string
to the standard output.
This is mostly useful for encrypting passwords from within scripts.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl b Ar rounds
Encrypt the string using Blowfish hashing with the specified
.Ar rounds .
.It Fl k
Run in
.Xr makekey 8
compatible mode.
A single combined key (eight chars) and salt (two chars) with no
intermediate space are read from standard input and the DES encrypted
result is written to standard output without a terminating newline.
.It Fl m
Hash the string using MD5.
.It Fl p
Prompt for a single string with echo turned off.
.It Fl S Ar rounds
Encrypt the salt with HMAC-SHA1 using the password as key and the specified
.Ar rounds
as a hint for the number of iterations.
.It Fl A Ar variant[,params]
Encrypt the specified string using Argon2 hashing parameterized using
variant
.Ar variant ,
where
.Ar variant
is one of the following: argon2id, argon2i, argon2d.  Variant
.Ar argon2id
is recommended.

Following the required
.Ar variant
name, three optional comma-delimited parameters may be provided,

t=n Specify the number of iterations to n.

m=n Specify the memory usage in KB  to n.

p=n Specify the number of threads to n.
This is currently ignored.

If unspecified, default parameters are calculated based on system
performance and available resources.
.It Fl s Ar salt
Encrypt the string using DES, with the specified
.Ar salt .
.El
.Pp
If no
.Ar string
is specified,
.Nm
reads one string per line from standard input, encrypting each one
with the chosen algorithm from above.
In the event that no specific algorithm is given as a command line option,
the algorithm specified in the default class in
.Pa /etc/passwd.conf
will be used.
.Pp
For MD5,  Blowfish, and Argon2 a new random salt is automatically generated for each
password.
.Pp
Specifying the
.Ar string
on the command line should be discouraged; using the
standard input is more secure.
.Sh EXAMPLES
The following specifies the argon2id variant, using 1 thread and 4096KB of memory

pwhash -A argon2id,p=1,m=4096 -p


.Sh FILES
.Bl -tag -width /etc/passwd.conf -compact
.It Pa /etc/passwd.conf
.El
.Sh SEE ALSO
.Xr crypt 3 ,
.Xr passwd.conf 5