Today, the Secretary joined her Spanish counterpart, Minister of Interior Alfredo Perez Rubalcaba, in giving keynote addresses to the International Conference of Data Protection and Privacy Commissioners in Madrid, Spain. This is the 31st annual data protection commissioner conference, but one of the few times when policy makers shared their views on data collection AND protections.

The conference hall was packed this morning, as privacy professionals from around the world crammed together to hear from royalty - the Prince of Asturias, the Spanish heir to the throne - and politicians alike.

The Secretary and the Minister both made clear that their vision of information sharing had to be consistent with privacy and civil liberties protection. Minister Rubalcaba began his speech with an emphatic statement - security and privacy are common principles, and can co-exist! He also warmly welcomed Secretary Napolitano, recognizing that her presence at this conference demonstrated the shared will of Europe and the US to work together.

Secretary Napolitano specifically acknowledged the completion of the work of the High Level Contact Group in crafting data protection principles, and encouraged movement towards a binding data protection agreement, stressing "what unites us far outweighs what divides us - including a long-standing respect for human rights and individual liberties."

As a privacy professional, this interaction between privacy leaders and policy leaders heralded a new era in transparency, one of the hallmarks of the Obama Administration; personally, it was heartening to witness this important dialogue. As both the Minister and Secretary Napolitano made clear, security and privacy can reinforce each other. At the Department of Homeland Security's Privacy Office, we try to implement this principle every day.

Mary Ellen Callahan is the Chief Privacy Officer for the Department of Homeland Security