1Crypt::Eksblowfish::BcrUyspetr(3C)ontributed Perl DocumeCnrtyaptti:o:nEksblowfish::Bcrypt(3)
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6 Crypt::Eksblowfish::Bcrypt - Blowfish-based Unix crypt() password hash
7
9 use Crypt::Eksblowfish::Bcrypt qw(bcrypt_hash);
10 $hash = bcrypt_hash({
12 key_nul => 1,
13 cost => 8,
14 salt => $salt,
15 }, $password);
16 use Crypt::Eksblowfish::Bcrypt qw(en_base64 de_base64);
18 $text = en_base64($octets);
20 $octets = de_base64($text);
21 use Crypt::Eksblowfish::Bcrypt qw(bcrypt);
23 $hashed_password = bcrypt($password, $settings);
25
27 This module implements the Blowfish-based Unix crypt() password hashing
28 algorithm, known as "bcrypt". This hash uses a variant of Blowfish,
29 known as "Eksblowfish", modified to have particularly expensive key
30 scheduling. Eksblowfish and bcrypt were devised by Niels Provos and
31 David Mazieres for OpenBSD. The design is described in a paper at
32 <http://www.usenix.org/events/usenix99/provos.html>.
33
35 bcrypt_hash(SETTINGS, PASSWORD)
36 Hashes PASSWORD according to the supplied SETTINGS, and returns the
37 23-octet hash. SETTINGS must be a reference to a hash, with these
38 keys:
39 key_nul
41 Truth value: whether to append a NUL to the password before
42 using it as a key. The algorithm as originally devised does
43 not do this, but it was later modified to do it. The version
44 that does append NUL is to be preferred; not doing so is
45 supported only for backward compatibility.
46 cost
48 Non-negative integer controlling the cost of the hash function.
49 The number of operations is proportional to 2^cost.
50 salt
52 Exactly sixteen octets of salt.
53 en_base64(BYTES)
55 Encodes the octet string textually using the form of base 64 that
56 is conventionally used with bcrypt.
57 de_base64(TEXT)
59 Decodes an octet string that was textually encoded using the form
60 of base 64 that is conventionally used with bcrypt.
61 bcrypt(PASSWORD, SETTINGS)
63 This is a version of "crypt" (see "crypt" in perlfunc) that
64 implements the bcrypt algorithm. It does not implement any other
65 hashing algorithms, so if others are desired then it necessary to
66 examine the algorithm prefix in SETTINGS and dispatch between more
67 than one version of "crypt".
68 SETTINGS must be a string which encodes the algorithm parameters,
70 including salt. It must begin with "$2", optional "a", "$", two
71 digits, "$", and 22 base 64 digits. The rest of the string is
72 ignored. The presence of the optional "a" means that a NUL is to
73 be appended to the password before it is used as a key. The two
74 digits set the cost parameter. The 22 base 64 digits encode the
75 salt. The function will "die" if SETTINGS does not have this
76 format.
77 The PASSWORD is hashed according to the SETTINGS. The value
79 returned is a string which encodes the algorithm parameters and the
80 hash: the parameters are in the same format required in SETTINGS,
81 and the hash is appended in the form of 31 base 64 digits. This
82 result is suitable to be used as a SETTINGS string for input to
83 this function: the hash part of the string is ignored on input.
84
86 Crypt::Eksblowfish, <http://www.usenix.org/events/usenix99/provos.html>
87
89 Andrew Main (Zefram) <zefram@fysh.org>
90
92 Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Andrew Main (Zefram)
93 <zefram@fysh.org>
94
96 This module is free software; you can redistribute it and/or modify it
97 under the same terms as Perl itself.
98perl v5.12.3 2011-04-30 Crypt::Eksblowfish::Bcrypt(3)