Digest::SHA1(3pm)

1SHA1(3)               User Contributed Perl Documentation              SHA1(3)
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NAME

6       Digest::SHA1 - Perl interface to the SHA-1 algorithm
7

SYNOPSIS

9        # Functional style
10        use Digest::SHA1  qw(sha1 sha1_hex sha1_base64);
11
12        $digest = sha1($data);
13        $digest = sha1_hex($data);
14        $digest = sha1_base64($data);
15        $digest = sha1_transform($data);
16
17        # OO style
18        use Digest::SHA1;
19
20        $sha1 = Digest::SHA1->new;
21
22        $sha1->add($data);
23        $sha1->addfile(*FILE);
24
25        $sha1_copy = $sha1->clone;
26
27        $digest = $sha1->digest;
28        $digest = $sha1->hexdigest;
29        $digest = $sha1->b64digest;
30        $digest = $sha1->transform;
31

DESCRIPTION

33       The "Digest::SHA1" module allows you to use the NIST SHA-1 message
34       digest algorithm from within Perl programs.  The algorithm takes as
35       input a message of arbitrary length and produces as output a 160-bit
36       "fingerprint" or "message digest" of the input.
37
38       The "Digest::SHA1" module provide a procedural interface for simple
39       use, as well as an object oriented interface that can handle messages
40       of arbitrary length and which can read files directly.
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FUNCTIONS

43       The following functions can be exported from the "Digest::SHA1" module.
44       No functions are exported by default.
45
46       sha1($data,...)
47           This function will concatenate all arguments, calculate the SHA-1
48           digest of this "message", and return it in binary form.  The
49           returned string will be 20 bytes long.
50
51           The result of sha1("a", "b", "c") will be exactly the same as the
52           result of sha1("abc").
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54       sha1_hex($data,...)
55           Same as sha1(), but will return the digest in hexadecimal form.
56           The length of the returned string will be 40 and it will only con‐
57           tain characters from this set: '0'..'9' and 'a'..'f'.
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59       sha1_base64($data,...)
60           Same as sha1(), but will return the digest as a base64 encoded
61           string.  The length of the returned string will be 27 and it will
62           only contain characters from this set: 'A'..'Z', 'a'..'z',
63           '0'..'9', '+' and '/'.
64
65           Note that the base64 encoded string returned is not padded to be a
66           multiple of 4 bytes long.  If you want interoperability with other
67           base64 encoded sha1 digests you might want to append the redundant
68           string "=" to the result.
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70       sha1_transform($data)
71           Implements the basic SHA1 transform on a 64 byte block. The $data
72           argument and the returned $digest are in binary form. This algo‐
73           rithm is used in NIST FIPS 186-2
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METHODS

76       The object oriented interface to "Digest::SHA1" is described in this
77       section.  After a "Digest::SHA1" object has been created, you will add
78       data to it and finally ask for the digest in a suitable format.  A sin‐
79       gle object can be used to calculate multiple digests.
80
81       The following methods are provided:
82
83       $sha1 = Digest::SHA1->new
84           The constructor returns a new "Digest::SHA1" object which encapsu‐
85           late the state of the SHA-1 message-digest algorithm.
86
87           If called as an instance method (i.e. $sha1->new) it will just
88           reset the state the object to the state of a newly created object.
89           No new object is created in this case.
90
91       $sha1->reset
92           This is just an alias for $sha1->new.
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94       $sha1->clone
95           This a copy of the $sha1 object. It is useful when you do not want
96           to destroy the digests state, but need an intermediate value of the
97           digest, e.g. when calculating digests iteratively on a continuous
98           data stream.  Example:
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100               my $sha1 = Digest::SHA1->new;
101               while (<>) {
102                   $sha1->add($_);
103                   print "Line $.: ", $sha1->clone->hexdigest, "\n";
104               }
105
106       $sha1->add($data,...)
107           The $data provided as argument are appended to the message we cal‐
108           culate the digest for.  The return value is the $sha1 object
109           itself.
110
111           All these lines will have the same effect on the state of the $sha1
112           object:
113
114               $sha1->add("a"); $sha1->add("b"); $sha1->add("c");
115               $sha1->add("a")->add("b")->add("c");
116               $sha1->add("a", "b", "c");
117               $sha1->add("abc");
118
119       $sha1->addfile($io_handle)
120           The $io_handle will be read until EOF and its content appended to
121           the message we calculate the digest for.  The return value is the
122           $sha1 object itself.
123
124           The addfile() method will croak() if it fails reading data for some
125           reason.  If it croaks it is unpredictable what the state of the
126           $sha1 object will be in. The addfile() method might have been able
127           to read the file partially before it failed.  It is probably wise
128           to discard or reset the $sha1 object if this occurs.
129
130           In most cases you want to make sure that the $io_handle is in "bin‐
131           mode" before you pass it as argument to the addfile() method.
132
133       $sha1->add_bits($data, $nbits)
134       $sha1->add_bits($bitstring)
135           This implementation of SHA-1 only supports byte oriented input so
136           you might only add bits as multiples of 8.  If you need bit level
137           support please consider using the "Digest::SHA" module instead.
138           The add_bits() method is provided here for compatibility with other
139           digest implementations.  See Digest for description of the argu‐
140           ments that add_bits() take.
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142       $sha1->digest
143           Return the binary digest for the message.  The returned string will
144           be 20 bytes long.
145
146           Note that the "digest" operation is effectively a destructive,
147           read-once operation. Once it has been performed, the "Digest::SHA1"
148           object is automatically "reset" and can be used to calculate
149           another digest value.  Call $sha1->clone->digest if you want to
150           calculate the digest without reseting the digest state.
151
152       $sha1->hexdigest
153           Same as $sha1->digest, but will return the digest in hexadecimal
154           form. The length of the returned string will be 40 and it will only
155           contain characters from this set: '0'..'9' and 'a'..'f'.
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157       $sha1->b64digest
158           Same as $sha1->digest, but will return the digest as a base64
159           encoded string.  The length of the returned string will be 27 and
160           it will only contain characters from this set: 'A'..'Z', 'a'..'z',
161           '0'..'9', '+' and '/'.
162
163           The base64 encoded string returned is not padded to be a multiple
164           of 4 bytes long.  If you want interoperability with other base64
165           encoded SHA-1 digests you might want to append the string "=" to
166           the result.
167

COPYRIGHT

174       This library is free software; you can redistribute it and/or modify it
175       under the same terms as Perl itself.
176
177        Copyright 1999-2004 Gisle Aas.
178        Copyright 1997 Uwe Hollerbach.
179

AUTHORS

181       Peter C. Gutmann, Uwe Hollerbach <uh@alumni.caltech.edu>, Gisle Aas
182       <gisle@aas.no>
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186perl v5.8.8                       2006-01-18                           SHA1(3)