Delete bundled copy of OpenSSL and replace with README.

openssl/crypto/des/des.pod

-=pod
-
-=head1 NAME
-
-des - encrypt or decrypt data using Data Encryption Standard
-
-=head1 SYNOPSIS
-
-B<des>
-(
-B<-e>
-|
-B<-E>
-) | (
-B<-d>
-|
-B<-D>
-) | (
-B<->[B<cC>][B<ckname>]
-) |
-[
-B<-b3hfs>
-] [
-B<-k>
-I<key>
-]
-] [
-B<-u>[I<uuname>]
-[
-I<input-file>
-[
-I<output-file>
-] ]
-
-=head1 NOTE
-
-This page describes the B<des> stand-alone program, not the B<openssl des>
-command.
-
-=head1 DESCRIPTION
-
-B<des>
-encrypts and decrypts data using the
-Data Encryption Standard algorithm.
-One of
-B<-e>, B<-E>
-(for encrypt) or
-B<-d>, B<-D>
-(for decrypt) must be specified.
-It is also possible to use
-B<-c>
-or
-B<-C>
-in conjunction or instead of the a encrypt/decrypt option to generate
-a 16 character hexadecimal checksum, generated via the
-I<des_cbc_cksum>.
-
-Two standard encryption modes are supported by the
-B<des>
-program, Cipher Block Chaining (the default) and Electronic Code Book
-(specified with
-B<-b>).
-
-The key used for the DES
-algorithm is obtained by prompting the user unless the
-B<-k>
-I<key>
-option is given.
-If the key is an argument to the
-B<des>
-command, it is potentially visible to users executing
-ps(1)
-or a derivative.  To minimise this possibility,
-B<des>
-takes care to destroy the key argument immediately upon entry.
-If your shell keeps a history file be careful to make sure it is not
-world readable.
-
-Since this program attempts to maintain compatibility with sunOS's
-des(1) command, there are 2 different methods used to convert the user
-supplied key to a des key.
-Whenever and one or more of
-B<-E>, B<-D>, B<-C>
-or
-B<-3>
-options are used, the key conversion procedure will not be compatible
-with the sunOS des(1) version but will use all the user supplied
-character to generate the des key.
-B<des>
-command reads from standard input unless
-I<input-file>
-is specified and writes to standard output unless
-I<output-file>
-is given.
-
-=head1 OPTIONS
-
-=over 4
-
-=item B<-b>
-
-Select ECB
-(eight bytes at a time) encryption mode.
-
-=item B<-3>
-
-Encrypt using triple encryption.
-By default triple cbc encryption is used but if the
-B<-b>
-option is used then triple ECB encryption is performed.
-If the key is less than 8 characters long, the flag has no effect.
-
-=item B<-e>
-
-Encrypt data using an 8 byte key in a manner compatible with sunOS
-des(1).
-
-=item B<-E>
-
-Encrypt data using a key of nearly unlimited length (1024 bytes).
-This will product a more secure encryption.
-
-=item B<-d>
-
-Decrypt data that was encrypted with the B<-e> option.
-
-=item B<-D>
-
-Decrypt data that was encrypted with the B<-E> option.
-
-=item B<-c>
-
-Generate a 16 character hexadecimal cbc checksum and output this to
-stderr.
-If a filename was specified after the
-B<-c>
-option, the checksum is output to that file.
-The checksum is generated using a key generated in a sunOS compatible
-manner.
-
-=item B<-C>
-
-A cbc checksum is generated in the same manner as described for the
-B<-c>
-option but the DES key is generated in the same manner as used for the
-B<-E>
-and
-B<-D>
-options
-
-=item B<-f>
-
-Does nothing - allowed for compatibility with sunOS des(1) command.
-
-=item B<-s>
-
-Does nothing - allowed for compatibility with sunOS des(1) command.
-
-=item B<-k> I<key>
-
-Use the encryption 
-I<key>
-specified.
-
-=item B<-h>
-
-The
-I<key>
-is assumed to be a 16 character hexadecimal number.
-If the
-B<-3>
-option is used the key is assumed to be a 32 character hexadecimal
-number.
-
-=item B<-u>
-
-This flag is used to read and write uuencoded files.  If decrypting,
-the input file is assumed to contain uuencoded, DES encrypted data.
-If encrypting, the characters following the B<-u> are used as the name of
-the uuencoded file to embed in the begin line of the uuencoded
-output.  If there is no name specified after the B<-u>, the name text.des
-will be embedded in the header.
-
-=head1 SEE ALSO
-
-ps(1),
-L<des_crypt(3)|des_crypt(3)>
-
-=head1 BUGS
-
-The problem with using the
-B<-e>
-option is the short key length.
-It would be better to use a real 56-bit key rather than an
-ASCII-based 56-bit pattern.  Knowing that the key was derived from ASCII
-radically reduces the time necessary for a brute-force cryptographic attack.
-My attempt to remove this problem is to add an alternative text-key to
-DES-key function.  This alternative function (accessed via
-B<-E>, B<-D>, B<-S>
-and
-B<-3>)
-uses DES to help generate the key.
-
-Be carefully when using the B<-u> option.  Doing B<des -ud> I<filename> will
-not decrypt filename (the B<-u> option will gobble the B<-d> option).
-
-The VMS operating system operates in a world where files are always a
-multiple of 512 bytes.  This causes problems when encrypted data is
-send from Unix to VMS since a 88 byte file will suddenly be padded
-with 424 null bytes.  To get around this problem, use the B<-u> option
-to uuencode the data before it is send to the VMS system.
-
-=head1 AUTHOR
-
-Eric Young (eay@cryptsoft.com)
-
-=cut