auto #lm_J2RP,mی- hauto Glm_JJj"T rS }_ub &=LV[(am_J2RP-\.1h)epackage Digest; use strict; use vars qw($VERSION %MMAP $AUTOLOAD); $VERSION = "1.17"; %MMAP = ( "SHA-1" => [["Digest::SHA", 1], "Digest::SHA1", ["Digest::SHA2", 1]], "SHA-224" => [["Digest::SHA", 224]], "SHA-256" => [["Digest::SHA", 256], ["Digest::SHA2", 256]], "SHA-384" => [["Digest::SHA", 384], ["Digest::SHA2", 384]], "SHA-512" => [["Digest::SHA", 512], ["Digest::SHA2", 512]], "HMAC-MD5" => "Digest::HMAC_MD5", "HMAC-SHA-1" => "Digest::HMAC_SHA1", "CRC-16" => [["Digest::CRC", type => "crc16"]], "CRC-32" => [["Digest::CRC", type => "crc32"]], "CRC-CCITT" => [["Digest::CRC", type => "crcccitt"]], "RIPEMD-160" => "Crypt::RIPEMD160", ); sub new { shift; # class ignored my $algorithm = shift; my $impl = $MMAP{$algorithm} || do { $algorithm =~ s/\W+//g; "Digest::$algorithm"; }; $impl = [$impl] unless ref($impl); local $@; # don't clobber it for our caller my $err; for (@$impl) { my $class = $_; my @args; ($class, @args) = @$class if ref($class); no strict 'refs'; unless (exists ${"$class\::"}{"VERSION"}) { my $pm_file = $class . ".pm"; $pm_file =~ s{::}{/}g; eval { require $pm_file }; if ($@) { $err ||= $@; next; } } return $class->new(@args, @_); } die $err; } sub AUTOLOAD { my $class = shift; my $algorithm = substr($AUTOLOAD, rindex($AUTOLOAD, '::')+2); $class->new($algorithm, @_); } 1; __END__ =head1 NAME Digest - Modules that calculate message digests =head1 SYNOPSIS $md5 = Digest->new("MD5"); $sha1 = Digest->new("SHA-1"); $sha256 = Digest->new("SHA-256"); $sha384 = Digest->new("SHA-384"); $sha512 = Digest->new("SHA-512"); $hmac = Digest->HMAC_MD5($key); =head1 DESCRIPTION The C modules calculate digests, also called "fingerprints" or "hashes", of some data, called a message. The digest is (usually) some small/fixed size string. The actual size of the digest depend of the algorithm used. The message is simply a sequence of arbitrary bytes or bits. An important property of the digest algorithms is that the digest is I to change if the message change in some way. Another property is that digest functions are one-way functions, that is it should be I to find a message that correspond to some given digest. Algorithms differ in how "likely" and how "hard", as well as how efficient they are to compute. Note that the properties of the algorithms change over time, as the algorithms are analyzed and machines grow faster. If your application for instance depends on it being "impossible" to generate the same digest for a different message it is wise to make it easy to plug in stronger algorithms as the one used grow weaker. Using the interface documented here should make it easy to change algorithms later. All C modules provide the same programming interface. A functional 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 digest can be delivered in three formats: =over 8 =item I This is the most compact form, but it is not well suited for printing or embedding in places that can't handle arbitrary data. =item I A twice as long string of lowercase hexadecimal digits. =item I A string of portable printable characters. This is the base64 encoded representation of the digest with any trailing padding removed. The string will be about 30% longer than the binary version. L tells you more about this encoding. =back The functional interface is simply importable functions with the same name as the algorithm. The functions take the message as argument and return the digest. Example: use Digest::MD5 qw(md5);