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Digest::SHA1 - Perl interface to the SHA-1 algorithm
# Functional style use Digest::SHA1 qw(sha1 sha1_hex sha1_base64);
$digest = sha1($data); $digest = sha1_hex($data); $digest = sha1_base64($data); $digest = sha1_transform($data);
# OO style use Digest::SHA1;
$sha1 = Digest::SHA1->new;
$sha1->add($data); $sha1->addfile(*FILE);
$sha1_copy = $sha1->clone;
$digest = $sha1->digest; $digest = $sha1->hexdigest; $digest = $sha1->b64digest; $digest = $sha1->transform;
The Digest::SHA1 module allows you to use the NIST SHA-1 message
digest algorithm from within Perl programs. The algorithm takes as
input a message of arbitrary length and produces as output a 160-bit
``fingerprint'' or ``message digest'' of the input.
The Digest::SHA1 module provide a procedural interface for simple
use, as well as an object oriented interface that can handle messages
of arbitrary length and which can read files directly.
The following functions can be exported from the Digest::SHA1
module. No functions are exported by default.
sha1($data,...)
This function will concatenate all arguments, calculate the SHA-1 digest of this ``message'', and return it in binary form. The returned string will be 20 bytes long.
The result of sha1(``a'', ``b'', ``c'') will be exactly the same as the result of sha1(``abc'').
sha1_hex($data,...)
Same as sha1(), but will return the digest in hexadecimal form. The length of the returned string will be 40 and it will only contain characters from this set: '0'..'9' and 'a'..'f'.
sha1_base64($data,...)
Same as sha1(), but will return the digest as a base64 encoded string. The length of the returned string will be 27 and it will only contain characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' and '/'.
Note that the base64 encoded string returned is not padded to be a multiple of 4 bytes long. If you want interoperability with other base64 encoded sha1 digests you might want to append the redundant string ``='' to the result.
sha1_transform($data)
Implements the basic SHA1 transform on a 64 byte block. The $data argument and the returned $digest are in binary form. This algorithm is used in NIST FIPS 186-2
The object oriented interface to Digest::SHA1 is described in this
section. After a Digest::SHA1 object has been created, you will add
data to it and finally ask for the digest in a suitable format. A
single object can be used to calculate multiple digests.
The following methods are provided:
The constructor returns a new Digest::SHA1 object which encapsulate
the state of the SHA-1 message-digest algorithm.
If called as an instance method (i.e. $sha1->new) it will just reset the state the object to the state of a newly created object. No new object is created in this case.
This is just an alias for $sha1->new.
This a copy of the $sha1 object. It is useful when you do not want to destroy the digests state, but need an intermediate value of the digest, e.g. when calculating digests iteratively on a continuous data stream. Example:
my $sha1 = Digest::SHA1->new;
while (<>) {
$sha1->add($_);
print "Line $.: ", $sha1->clone->hexdigest, "\n";
}
add($data,...)
The $data provided as argument are appended to the message we calculate the digest for. The return value is the $sha1 object itself.
All these lines will have the same effect on the state of the $sha1 object:
$sha1->add("a"); $sha1->add("b"); $sha1->add("c");
$sha1->add("a")->add("b")->add("c");
$sha1->add("a", "b", "c");
$sha1->add("abc");
addfile($io_handle)
The $io_handle will be read until EOF and its content appended to the message we calculate the digest for. The return value is the $sha1 object itself.
The addfile() method will croak() if it fails reading data for some
reason. If it croaks it is unpredictable what the state of the $sha1
object will be in. The addfile() method might have been able to read
the file partially before it failed. It is probably wise to discard
or reset the $sha1 object if this occurs.
In most cases you want to make sure that the $io_handle is in
binmode before you pass it as argument to the addfile() method.
add_bits($bitstring)
This implementation of SHA-1 only supports byte oriented input so you
might only add bits as multiples of 8. If you need bit level support
please consider using the Digest::SHA module instead. The
add_bits() method is provided here for compatibility with other digest
implementations. See the Digest manpage for description of the arguments that
add_bits() take.
Return the binary digest for the message. The returned string will be 20 bytes long.
Note that the digest operation is effectively a destructive,
read-once operation. Once it has been performed, the Digest::SHA1
object is automatically reset and can be used to calculate another
digest value. Call $sha1->clone->digest if you want to calculate the
digest without reseting the digest state.
Same as $sha1->digest, but will return the digest in hexadecimal form. The length of the returned string will be 40 and it will only contain characters from this set: '0'..'9' and 'a'..'f'.
Same as $sha1->digest, but will return the digest as a base64 encoded string. The length of the returned string will be 27 and it will only contain characters from this set: 'A'..'Z', 'a'..'z', '0'..'9', '+' and '/'.
The base64 encoded string returned is not padded to be a multiple of 4 bytes long. If you want interoperability with other base64 encoded SHA-1 digests you might want to append the string ``='' to the result.
the Digest manpage, the Digest::HMAC_SHA1 manpage, the Digest::SHA manpage, the Digest::MD5 manpage
http://www.itl.nist.gov/fipspubs/fip180-1.htm
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Copyright 1999-2004 Gisle Aas. Copyright 1997 Uwe Hollerbach.
Peter C. Gutmann, Uwe Hollerbach <uh@alumni.caltech.edu>, Gisle Aas <gisle@aas.no>