For the payroll scenario, that's probably prudent. But if you're storing
customer data that is not easily open to an inference-type attack such as
that described, one-way hashes along with reversible encryption can be used
to still have sorting and query abilities without doing bulk column
decryption before Db querying. This can yield a significant performance
boost with little increase in residual risk.
Fred Langston, CISSP
Senior Principal Consultant
W: 206.903.8147 x223 F: 206.903.1862 M: 425.765.3330
Seattle, WA www.Guardent.com
________________________________________
G U A R D E N T
Enterprise Security and Privacy Programs
-----Original Message-----
From: Sasha [mailto:nospam (at) mail (dot) com [email concealed]]
Sent: Monday, January 19, 2004 2:02 AM
To: focus-ms (at) securityfocus (dot) com [email concealed]
Subject: RE: Encrypt data - SQL Server 2000
On Fri, 16 Jan 2004, Kevin E. Casey wrote:
> If you need to encrypt data in 3 columns and 3 columns only, your best
> bet is to do the encryption at the application (in its data tier)
> level. Using .NET (or other tools), gives you a good range/assortment
> of tools and sencryption schemes to encrypt that confidential data.
> This keeps your DBAs from snooping around. Keeps backup copies safe
> from prying eyes and it also keeps the performance hit for
> en/decryption at the client (or web server level).
Just make sure that you use an encryption which do not produce the same
result twice. That is if you always encrypt 50000 to ABCDE, it will be very
easy to find which rows have the same value and thus who have the same
salaries.
customer data that is not easily open to an inference-type attack such as
that described, one-way hashes along with reversible encryption can be used
to still have sorting and query abilities without doing bulk column
decryption before Db querying. This can yield a significant performance
boost with little increase in residual risk.
Fred Langston, CISSP
Senior Principal Consultant
W: 206.903.8147 x223 F: 206.903.1862 M: 425.765.3330
Seattle, WA www.Guardent.com
________________________________________
G U A R D E N T
Enterprise Security and Privacy Programs
-----Original Message-----
From: Sasha [mailto:nospam (at) mail (dot) com [email concealed]]
Sent: Monday, January 19, 2004 2:02 AM
To: focus-ms (at) securityfocus (dot) com [email concealed]
Subject: RE: Encrypt data - SQL Server 2000
On Fri, 16 Jan 2004, Kevin E. Casey wrote:
> If you need to encrypt data in 3 columns and 3 columns only, your best
> bet is to do the encryption at the application (in its data tier)
> level. Using .NET (or other tools), gives you a good range/assortment
> of tools and sencryption schemes to encrypt that confidential data.
> This keeps your DBAs from snooping around. Keeps backup copies safe
> from prying eyes and it also keeps the performance hit for
> en/decryption at the client (or web server level).
Just make sure that you use an encryption which do not produce the same
result twice. That is if you always encrypt 50000 to ABCDE, it will be very
easy to find which rows have the same value and thus who have the same
salaries.
Regards,
ASK
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