More SQL Encryption

["Mike Pantzopoulos - \(H/O\)" <mpantzopoulos@xxxxxxxxxxxxxxxx>]

What I'm trying to do is encrypt is a single column for selected records
so that when the file is being read the program won't know if the data
is encrypted or not. This is ok as for normal use as the correct
security is being implemented. In other words, an encrypted field will
appear as encrypted data and an unencrypted value will also appear in
it's correct form.

I've tried this on my test file and it works correctly.

The problem arises when an authorised user needs to view data in it's
unencrypted form. When I run the DECRYPT function over the above data,
it fails, presumably because the rows with unencrypted data are not
recognized by the select with the DECRYPT function. The following fails:

SELECT decrypt_char(card,'abcdef') FROM           
anvmxp/encrypt                                    
Query cannot be run.  See lower level messages.   

The lower level messages are as follows:

 Function DECRYPT_CHAR cannot be run.            
 User-defined function error on member ENCRYPT.  
 Function DECRYPT_CHAR cannot be run.            
 User-defined function error on member ENCRYPT.  
 Function DECRYPT_CHAR cannot be run.            
 User-defined function error on member ENCRYPT.  

The obvious question is to ask if there is any way of identifying if a
field is encrypted and to issue the correct select statement
accordingly. Or is there some other error trapping process I can use?




Mike Pantzopoulos

EIG-Ansvar Limited
Tel  : 61 (3) 9614 3535
Fax: 61 (3) 9614 2740



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