INTRODUCTION • Policy-making and implementation • Necessary to deal with societal problems • Policy interventions • Costly • Long-term implications • May affect large groups of people • Not easy to undo COMPLEXITY AND UNCERTAINTY • Ongoing process • Recognize issue as problem • Develop alternative course of action • Create or alter policy • Implement policy • Execute policy • Evaluate policy POLICY CYCLE AND STAKEHOLDERS DEVELOPMENTS • New technology that affects policy process • Social media • Blogs • Open data • Freedom of information • Wisdom of the crowds • Open collaboration • Transparency in policy simulation • Agent-based simulation and hybrid modeling techniques COMBINING DISCIPLINES • New field is known by different names • ePolicy-making • Digital policy science • Computational intelligence • Digital science / Data science • Policy informatics • Multidisciplinary • Requires expertise from wide range of disciplines SUMMARY • Policy-making is changing due to technology • Technology can help to develop more effective policy • Integrating technology requires substantial effort • Many types of technology • Requires different levels of expertise • All technology is not helpful for each situation • Emerging need for inter-disciplinary specialists Chapter 8 Finding Lost Files 1 Old Files Never Die Deleting a file doesn’t erase data Even a wiped file may leave behind artifacts Remnants of old files may remain in slack space or unallocated space Temporary files may still exist or be recoverable Some files aren’t deleted, but rather intentionally hidden OS File Recovery Deleting a file sends it to the “Trash” or “Recycle Bin” File is simply renamed and moved to a hidden folder Deleting the file from Recycle marks the space used by the file as available (but does not erase data) Using a WIPE utility overwrites the data on the medium with random characters What is Slack Space? Hard disks are divided into clusters of 4 to 32KB If a file does not fill a cluster, the remainder of the cluster is not overwritten, nor is it available Slack space also exists between partitions on a physical disk Utilities such as Slacker can harness all this space into a usable file system What is Unallocated Space? When a disk is formatted, each cluster is identified and mapped When a file is created or copied to the system, the file system marks the clusters it occupies as “allocated” When a file is removed from Recycle, the clusters aren’t erased, but merely marked as “unallocated” Unallocated space can hold a lot of data Recovering Deleted Files Specialized utilities read the file system metadata and identify clusters where files once lived If the space has not been overwritten, the files can be recovered intact Mark space as allocated Give the file a new name Disk editing utilities allow the residual data from partially overwritten files to be copied to a new file Data Carving Files in unallocated ...

1. INTRODUCTION
• Policy-making and implementation
• Necessary to deal with societal problems
• Policy interventions
• Costly
• Long-term implications
• May affect large groups of people
• Not easy to undo
COMPLEXITY AND UNCERTAINTY
• Ongoing process
• Recognize issue as problem
• Develop alternative course of action
• Create or alter policy
• Implement policy
• Execute policy

2. • Evaluate policy
POLICY CYCLE AND STAKEHOLDERS
DEVELOPMENTS
• New technology that affects policy process
• Social media
• Blogs
• Open data
• Freedom of information
• Wisdom of the crowds
• Open collaboration
• Transparency in policy simulation
• Agent-based simulation and hybrid modeling techniques
COMBINING DISCIPLINES
• New field is known by different names
• ePolicy-making
• Digital policy science

3. • Computational intelligence
• Digital science / Data science
• Policy informatics
• Multidisciplinary
• Requires expertise from wide range of disciplines
SUMMARY
• Policy-making is changing due to technology
• Technology can help to develop more effective policy
• Integrating technology requires substantial effort
• Many types of technology
• Requires different levels of expertise
• All technology is not helpful for each situation
• Emerging need for inter-disciplinary specialists
Chapter 8
Finding Lost Files
1

4. Old Files Never Die
Deleting a file doesn’t erase data
Even a wiped file may leave behind artifacts
Remnants of old files may remain in slack space or unallocated
space
Temporary files may still exist or be recoverable
Some files aren’t deleted, but rather intentionally hidden
OS File Recovery
Deleting a file sends it to the “Trash” or “Recycle Bin”
File is simply renamed and moved to a hidden folder
Deleting the file from Recycle marks the space used by the file
as available (but does not erase data)
Using a WIPE utility overwrites the data on the medium with
random characters
What is Slack Space?
Hard disks are divided into clusters of 4 to 32KB
If a file does not fill a cluster, the remainder of the cluster is
not overwritten, nor is it available
Slack space also exists between partitions on a physical disk
Utilities such as Slacker can harness all this space into a usable
file system
What is Unallocated Space?
When a disk is formatted, each cluster is identified and mapped
When a file is created or copied to the system, the file system
marks the clusters it occupies as “allocated”
When a file is removed from Recycle, the clusters aren’t erased,
but merely marked as “unallocated”
Unallocated space can hold a lot of data

5. Recovering Deleted Files
Specialized utilities read the file system metadata and identify
clusters where files once lived
If the space has not been overwritten, the files can be recovered
intact
Mark space as allocated
Give the file a new name
Disk editing utilities allow the residual data from partially
overwritten files to be copied to a new file
Data Carving
Files in unallocated space can be retrieved by “data carving”
All bits stored on the medium beginning with a file header and
going through to an end of file marker are copied to a new file
Few utilities can salvage files stored on noncontiguous clusters
Data Carving Tools
Carver
Foremost
Scalpel