Add some examples to the enc man page.

A password will be prompted for to derive the key and IV if necessary.

Some of the ciphers do not have large keys and others have security

implications if not used correctly. A beginner is advised to just use

a strong block cipher in CBC mode such as bf or des3.

All the block ciphers use PKCS#5 padding also known as standard block

padding: this allows a rudimentary integrity or password check to be

performed. However since the chance of random data passing the test is

=head1 EXAMPLES

To be added....

Just base64 encode a binary file:

 openssl base64 -in file.bin -out file.b64

Decode the same file

 openssl base64 -d -in file.b64 -out file.bin 

Encrypt a file using triple DES in CBC mode using a prompted password:

 openssl des3 -in file.txt -out file.des3 

Decrypt a file using a supplied password:

 openssl des3 -d -in file.des3 -out file.txt -k mypassword

Encrypt a file then base64 encode it (so it can be sent via mail for example)

using Blowfish in CBC mode:

 openssl bf -a -in file.txt -out file.bf

Base64 decode a file then decrypt it:

 openssl bf -d -a -in file.bf -out file.txt

Decrypt some data using a supplied 40 bit RC4 key:

 openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405

=head1 BUGS

The B<-A> option when used with large files doesn't work properly.

The key derivation algorithm used is compatible with the SSLeay algorithm. It

is not very good: it uses unsalted MD5. There should be an option to allow a

salt or iteration count to be included.

is not very good: it uses unsalted MD5.

There should be an option to allow a salt or iteration count to be included.

Like the EVP library the B<enc> program only supports a fixed number of

algorithms with certain parameters. So if, for example, you want to use RC2