1This is an implementation of a password hashing method, provided via the
2crypt(3) and a reentrant interface.  It is mostly compatible with
3OpenBSD's bcrypt.c (prefix "$2a$") by Niels Provos and David Mazieres.
4(Please refer to the included crypt(3) man page for information on
5compatibility issues.)
6
7I've placed this code in the public domain, with fallback to a
8permissive license.  Please see the comment in crypt_blowfish.c for
9more information.
10
11You can use the provided routines in your own packages, or link them
12into a C library.  I've provided hooks for linking into GNU libc, but
13it shouldn't be too hard to get this into another C library.  Note
14that simply adding this code into your libc is probably not enough to
15make your system use the new password hashing algorithm.  Changes to
16passwd(1), PAM modules, or whatever else your system uses will likely
17be needed as well.  These are not a part of this package, but see
18LINKS for a pointer to our tcb suite.
19
20Instructions on using the routines in one of the two common ways are
21given below.  It is recommended that you test the routines on your
22system before you start.  Type "make check" or "make check_threads"
23(if you have the POSIX threads library), then "make clean".
24
25
261. Using the routines in your programs.
27
28The available interfaces are in ow-crypt.h, and this is the file you
29should include.  You won't need crypt.h.  When linking, add all of the
30C files and x86.S (you can compile and link it even on a non-x86, it
31will produce no code in this case).
32
33
342. Building the routines into GNU C library.
35
36For versions 2.13 and 2.14 (and likely other nearby ones), extract the
37library sources as usual.  Apply the patch for glibc 2.14 provided in
38this package.  Enter crypt/ and rename crypt.h to gnu-crypt.h within
39that directory.  Copy the C sources, header, and assembly (x86.S) files
40from this package in there as well (but be sure you don't overwrite the
41Makefile).  Configure, build, and install the library as usual.
42
43For versions 2.2 to 2.3.6 (and likely also for some newer ones),
44extract the library sources and maybe its optional add-ons as usual.
45Apply the patch for glibc 2.3.6 provided in this package.  Enter
46crypt/ and rename crypt.h to gnu-crypt.h within that directory.  Copy
47the C sources, header, and assembly (x86.S) files from this package in
48there as well (but be sure you don't overwrite the Makefile).
49Configure, build, and install the library as usual.
50
51For versions 2.1 to 2.1.3, extract the library sources and the crypt
52and linuxthreads add-ons as usual.  Apply the patch for glibc 2.1.3
53provided in this package.  Enter crypt/sysdeps/unix/, and rename
54crypt.h to gnu-crypt.h within that directory.  Copy C sources, header,
55and assembly (x86.S) files from this package in there as well (but be
56sure you don't overwrite the Makefile).  Configure, build, and install
57the library as usual.
58
59Programs that want to use the provided interfaces will need to include
60crypt.h (but not ow-crypt.h directly).  By default, prototypes for the
61new routines aren't defined (but the extra functionality of crypt(3)
62is indeed available).  You need to define _OW_SOURCE to obtain the new
63routines as well.
64
65--
66Solar Designer <solar at openwall.com>
67
68$Owl: Owl/packages/glibc/crypt_blowfish/README,v 1.9 2011/07/16 21:48:45 solar Exp $
69