NAME

       Crypt::CipherSaber - Perl module implementing CipherSaber encryption.

SYNOPSIS

         use Crypt::CipherSaber;
         my $cs = Crypt::CipherSaber->new('my pathetic secret key');

         my $coded = $cs->encrypt('Here is a secret message for you');
         my $decoded = $cs->decrypt($coded);

         # encrypt from and to a file
         open(INFILE, 'secretletter.txt') or die "Can't open infile: $!";
         open(OUTFILE, '>secretletter.cs1') or die "Can't open outfile: $!";
         binmode(INFILE);
         binmode(OUTFILE);
         $cs->fh_crypt(\*INFILE, \*OUTFILE, 1);

         # decrypt from and to a file
         open(INFILE, 'secretletter.cs1') or die "Can't open infile: $!";
         open(OUTFILE, '>secretletter.txt') or die "Can't open outfile: $!";
         binmode(INFILE);
         binmode(OUTFILE);
         $cs->fh_crypt(\*INFILE, \*OUTFILE);

DESCRIPTION

       The Crypt::CipherSaber module implements CipherSaber encryption, described at
       http://ciphersaber.gurus.com.  It is simple, fairly speedy, and relatively secure
       algorithm based on RC4.

       Encryption and decryption are done based on a secret key, which must be shared with all
       intended recipients of a message.

METHODS

       new($key, $N)
           Initialize a new Crypt::CipherSaber object.  $key, the key used to encrypt or to
           decrypt messages is required.  $N is optional.  If provided and greater than one, it
           will implement CipherSaber-2 encryption (slightly slower but more secure).  If not
           specified, or equal to 1, the module defaults to CipherSaber-1 encryption.  $N must be
           a positive integer greater than one.

       encrypt($message)
           Encrypt a message.  This uses the key stored in the current Crypt::CipherSaber object.
           It will generate a 10-byte random IV (Initialization Vector) automatically, as defined
           in the RC4 specification.  This returns a string containing the encrypted message.

           Note that the encrypted message may contain unprintable characters, as it uses the
           extended ASCII character set (valid numbers 0 through 255).

       decrypt($message)
           Decrypt a message.  For the curious, the first ten bytes of an encrypted message are
           the IV, so this must strip it off first.  This returns a string containing the
           decrypted message.

           The decrypted message may also contain unprintable characters, as the CipherSaber
           encryption scheme can handle binary files with fair ease.  If this is important to
           you, be sure to treat the results correctly.

       crypt($iv, $message)
           If you wish to generate the IV with a more cryptographically secure random string (at
           least compared to Perl's builtin rand() function), you may do so separately, passing
           it to this method directly.  The IV must be a ten-byte string consisting of characters
           from the extended ASCII set.

           This is generally only useful for encryption, although you may extract the first ten
           characters of an encrypted message and pass them in yourself.  You might as well call
           decrypt(), though.  The more random the IV, the stronger the encryption tends to be.
           On some operating systems, you can read from /dev/random.  Other approaches are the
           Math::TrulyRandom module, or compressing a file, removing the headers, and compressing
           it again.

       fh_crypt(\*INPUT, \*OUTPUT, ($iv))
           For the sake of efficiency, Crypt::CipherSaber can now operate on filehandles.  It's
           not super brilliant, but it's relatively fast and sane.  Pass in a reference to the
           input file handle and the output filehandle.  If your platform needs to use
           "binmode()", this is your responsibility.  It is also your responsibility to close the
           files.

           You may also pass in an optional third parameter, an IV.  There are three
           possibilities here.  If you pass no IV, "fh_crypt()" will pull the first ten bytes
           from *INPUT and use that as an IV.  This corresponds to decryption.  If you pass in an
           IV of your own (generally ten digits, but more than one digits as the code is now), it
           will use your own IV when encrypting the file.  If you pass in the value '1', it will
           generate a new, random IV for you.  This corresponds to an encryption.

COPYRIGHT AND LICENSE

       Copyright (C) 2000 - 2001 chromatic

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

AUTHOR

       chromatic <chromatic@wgz.org>

       thanks to jlp for testing, moral support, and never fearing the icky details and to the
       fine folks at http://perlmonks.org

       Additional thanks to Olivier Salaun and the Sympa project (http://www.sympa.org) for
       testing.

SEE ALSO

       the CipherSaber home page at http://ciphersaber.gurus.com

       perl(1), rand().