Ubuntu Manpage: Crypt::CipherSaber - Perl module implementing CipherSaber encryption.

Provided by: libcrypt-ciphersaber-perl_0.61-4.2_all

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