Protect Your Data's

Privacy! Data Encryption with

SQL ServerJoe Kuemerle@jkuemerle

www.kuemerle.com

Background of Joe Kuemerle

• Lead Developer at BookingBuilder Technologies

• Over 15 years of development experience with a

broad range of technologies

• Focused on application and data security, coding

best practices and regulatory compliance

• Presenter at community, regional and national

events.

What Is Encryption

What Is Encryption• Encryption is the process of mathematically

altering data in a consistent, reversible fashion. It should be used to store sensitive information that will need to be retrieved later. Encryption relies on a secret that is the only viable way to reverse the mathematical process

• Encryption can be Symmetric where a single value (the encryption key) is used to both encrypt and decrypt the data

• Or Encryption can be Asymmetric where there are two values in that data encrypted with Value 1 can only be decrypted with Value 2 and vice versa. This is also know as Public Key Encryption

What Is Encryption“Encryption is the process of substituting a small secret in place of a large secret”

Symmetric Encryption

Asymmetric Encryption

Certificates• Certificates are used to store asymmetric keys

and consist of a private key and public key.• SQL Server provides built in management of

certificates• Do not use use certificates to encrypt data, it is

slow and can be vulnerable when storing lengthy values. Use a symmetric key to encrypt the data and a certificate to encrypt the symmetric key.

Hashes• Hashes are not an encryption method. A hash

takes an input value and transforms it to a unique value that is infeasible to convert back to the original value.

• Hashes are not for storing data that needs to be re-read but are for proving knowledge of a secret without the actual secret being revealed.

• Hashes are ideal for verifying passwords. The actual password is unimportant we just need to have the user prove that they know the password.

Hashes• Best practices call for the use of SHA256,

SHA384, SHA512 or higher functions• Bcrypt is a “Future-Adaptable” open source

hashing algorithm• Do not use MD5 or SHA1as there are proven

methods for undermining the hash results.

• SQL Server 2005/2008 only support MD5 & SHA1, Denali supports SHA256SHA384 and SHA512

Demos• Yay! No more bullet points.

All source code is available on CodePlex:

http://sqlcrypto.codeplex.com/

References• Laurentiu Christofor: http://blogs.msdn.com/lcris/• Raul Garcia: http://blogs.msdn.com/raulga• Bruce Schneier: http://www.schneier.com/• http://

blogs.msdn.com/b/sqlsecurity/archive/2010/06/14/database-encryption-key-dek-management.aspx

• Cryptography:o http://www.garykessler.net/library/crypto.htmlo http://www.cacr.math.uwaterloo.ca/hac/

• BCrypt:o http://

chargen.matasano.com/chargen/2007/9/7/enough-with-the-rainbow-tables-what-you-need-to-know-about-s.html

o http://codahale.com/how-to-safely-store-a-password/o http://

derekslager.com/blog/posts/2007/10/bcrypt-dotnet-strong-password-hashing-for-dotnet-and-mono.ashx

• Demo source: http://sqlcrypto.codeplex.com

@jkuemerle / joe at kuemerle.comhttp://www.speakerrate.com/jkuemerle

Photo Credits• http://

www.flickr.com/photos/wwworks/4612188594• http://www.flickr.com/photos/joyosity/3358614462• http://

www.flickr.com/photos/jmrosenfeld/315825815• http://

www.flickr.com/photos/23258385@N04/2225809637

• http://www.flickr.com/photos/chelseamcnamara/4058966236

• http://xkcd.com/538/